The World of Ham Radio CD-ROM From amsoft@epix.net Fri May 03 12:10:20 1996 From: Ted F Newsgroups: rec.radio.amateur.antenna Subject: 2 meter Beam Date: Wed, 01 May 1996 11:26:07 -0400 Message-ID: <3187828F.6E0A@telerama.lm.com> This might be a stupid question, but i'll ask anyway. In the April issue of 7 3 on page 54 there is an article about a 3 element direct connect beam antenna that is e asy to construct. The only question I have is, what type of transmission line to use with it. The way it looks in the pictures, I am guessing twin lead ladder line. Coax would be better for me as I have a surplus of rg-8 I can use. Thanks in advance for yo ur help. Ted F. N3SQY From amsoft@epix.net Fri May 03 12:10:21 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: 50 ohms from ladder-line Date: 30 Apr 1996 23:14:01 -0700 Message-ID: <4m6vf9$9r1@nnrp1.news.primenet.com> References: <4m48b6$iv2@chnews.ch.intel.com> cmoore@vegas.ch.intel.com (Cecil A. Moore~) wrote: >Think of it. A perfect 50 ohm match using a single variable >capacitor from my junk box. Who said balanced antenna tuners >were expensive and complicated? Got some more data. The 50 ohm (actually 1/50 S) unit conductance circle on a 300 ohm Smith chart is drawn through points 0+j0 and 0.167+j0, a rather small circle close to the current maximum points. That means a single parallel reactance placed within 0.013 wavelengths of the current maximum will result in a perfect 50 ohms for any 300 ohm ladder-line SWR above 6:1 I've done it for 10m-20m with a single 20-200pf variable capacitor. 73, Cecil, KG7BK, OOTC From amsoft@epix.net Fri May 03 12:10:22 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: 50 ohms from ladder-line Date: 30 Apr 1996 23:24:02 -0700 Message-ID: <4m7022$anj@nnrp1.news.primenet.com> References: <4m48b6$iv2@chnews.ch.intel.com> <31868D8D.3064@haven.ios.com> Larry Deering wrote: > I hope that you are using a 1:1 balun between the xmtr and balanced >line, or do you have a balanced output from the xmtr? Just a plain old bead choke. Don't have any RF-in-the-shack problems. 73, Cecil, KG7BK, OOTC From amsoft@epix.net Fri May 03 12:10:23 1996 From: plove@quux.apana.ORG.AU (Paul Love) Newsgroups: rec.radio.amateur.antenna Subject: 6 metre J Pole Date: 1 May 96 09:13:59 GMT Message-ID: >Date: Thu, 25 Apr 1996 01:35:30 GMT >From: raiar@inlink.com (Gary V. Deutschmann, Sr.) >Subject: 6 meter J- Pole >michaels@computize.com (Michael W. Smith II) wrote: >It seems that there is a lot of action/questions about J poles....I'm >looking to build a 6 meter jpole. There are some articles about >construction, but there are in the 1950's magazines. I was wondering >if anyone had built a 6 meter j pole and could give me some ideas on >how to build one, or some starting dimensions. Thanks alot!! >73's >N5TGL >Michael W. Smith II >I use a mirror image J on 6-m.... >By using a simple solenoid, I can flip it from vertical to horizontal. >Plans available on my web page http://www.inlink.com/~raiar >TTUL - 73+ de Gary - KG0ZP ------------------------------ Michael there are dimensions in most ARRL Antenna handbooks, and Gary's suggestion is interesting. I have been having a discussion about this same topic on the HAM_TECH fido conf. and the suggestion was made that they are so cheap to build you could mount one horizontally off the side on your tower mounted at the bottom "U" but facing out that way---> , without upsetting the radiation pattern of the antenna. With one cut for the top FM band and another for the SSB DX end you get the best of both world cheaply, but Gary's suggestion goes one step further. 73 & Have Fun.....Paul VK4XD. *************************************************************************** * E-Mail : plove@quux.apana.org.au | AMPRNET:vk4xd@vk4xd.ampr.org * * AX25: vk4xd @ vk4rzb.#bne.qld.aus.oc | IP :[44.136.138.118] * *************************************************************************** From amsoft@epix.net Fri May 03 12:10:24 1996 From: raiar@inlink.com (Gary V. Deutschmann, Sr.) Newsgroups: rec.radio.amateur.antenna Subject: Re: 6 metre J Pole (UPDATE) Date: Thu, 02 May 1996 17:27:36 GMT Message-ID: <4marg9$7ni@news2.inlink.com> References: Did an experiment last weekend. Built a combination 6-meter mirror image J-Pole combining both vertical and horizontal elements. I stumbled across a couple of double T-Fittings, actually an X-Fitting with T in the center, made of brass for a couple of bucks each. My evil mind concocted a double mirrored-J, thus I built it. As it turned out, I had to use two pieces of 59U coax, exactly 1/2 wavelength long, one to the vertical and one to the horizontal transformer. These two pieces of coax were joined and then any length of 50 ohm coax can be used for the trip back to the shack. It took about 10 tries at feeding this monstrosity before I hit on the combination that gave me less than 1.2-1 SWR. The antenna operates vertically and horizontally at the same time. I don't have any technical data on it yet, but in comparison to the single mirrored image J-Pole. The received signal on the combo vs the vertical from our local repeater was 1.5 S units higher. The received signal on the combo vs the horizontal was only 1 S unit higher, but our repeater is vertical. A QSO with a ham about 30 miles away on a horizontal dipole, showed the following. Received signal on the new combo antenna was a full 10 over S 9. Received signal on the vertical mirrored-J was only 6 S units. Switching it to horizontal raised the received signal to 8.5 S units. Transmitting at 20 watts my signal was received at 15 over S 9 using the combo antenna. The vertical was only received at 5 S units and the horizontal was received at 9 S units. Feeding the combo with a single feedline to the vertical, showed no improvement over a regular mirrored vertical-J. Once the Co-Phasing harness was built, installed and tuned for lowest SWR, the difference was dramatic enough to mention it here. TTUL - 73+ de Gary - KG0ZP http://www.inlink.com/~raiar From amsoft@epix.net Fri May 03 12:10:25 1996 From: forrest.gehrke@cencore.com (FORREST GEHRKE) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Modeling Sof˙˙˙˙˙ Message-ID: <8BFC2A2.02CF00103B.uuout@cencore.com> Date: Wed, 01 May 96 11:14:00 -0300 Distribution: world Reply-To: forrest.gehrke@cencore.com (FORREST GEHRKE) References: <31830EBD.589A@vtx.ch> CM> >OS/2? What's that? =8~} CM> Hi Jim, isn't that an old obsolete operating system like CPM? :-) * RM 1.3 02583 * Windows95? Been There,..Done That,..2 Years Ago!!... OS/2 From amsoft@epix.net Fri May 03 12:10:26 1996 From: dnorris@k7no.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Theory Question Date: Wed, 01 May 1996 14:18:46 GMT Message-ID: <4m7rrd$lk8@news.syspac.com> References: <4l80tb$t7h@newsbf02.news.aol.com> <4ltst7$3rp@nnrp1.news.primenet.com> <7vtAUGAacygxEwYH@ifwtech.demon.co.uk> <4m0veu$27a@nnrp1.news.primenet.com> <4m2ps4$1sbc@info4.rus.uni-stuttgart.de> moritz@ipers1.e-technik.uni-stuttgart.de () wrote: >>We have proven that faster than light communications occurs. >>We have proven that EM waves do not follow straight lines and >>cannot propagate through nothing. >Wrong news group, Cecil, >Take it to alt.scifi.weird. >73, Moritz DL5UH Perhaps this will explain some curious phenomena... Administratium World's Heaviest Element Discovered The heaviest element known to science was recently discovered by University of Adelaide physicists. The element, tentatively named Administratium has no proton and no electrons and thus has atomic weight of 0. However, it does have one neutron, 12 assistant neutrons, 70 vice-neutrons and 161 assistant vice-neutrons. This gives it an atomic mass of 244. These 244 particles are held together in a nucleus by a strong force that involves the continuous exchange of meson-like particles called morons. Since it has no electrons, Administratium is inert. However, it can be detected chemically as it impedes every reaction it comes into contact with. According to researchers, in one experiment, a minute amount of Administratium was added to a reaction, which took four days to complete. Without Administratium, the reaction ordinarily took less than one second. Administratium has a normal half-life of approximately three years, at which time it does not actually decay, but instead undergoes a reorganisation in which assistant neutrons, vice neutrons and assistant vice-neutrons exchange places. Preliminary studies show that the atomic number actually increase after reorganisation. Research indicates that Administratium occurs naturally in the atmosphere, but it tends to concentrate in artificial structures build on lower tender such as government agencies and universities. It can usually be found in the newest, best appointed and best maintained buildings. Scientists warn that Administratium is known to be toxic and recommend plenty of red and white fluids and bed rest after exposure to even low levels of the element. 73/DX C. Dean Norris Amateur Radio Station K7NO e-mail to dnorris@k7no.com http://www.syspac.com/~dnorris/ From amsoft@epix.net Fri May 03 12:10:28 1996 From: "Ian White, G3SEK" Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Theory Question Date: Wed, 1 May 1996 09:13:52 +0100 Distribution: world Message-ID: References: <4l80tb$t7h@newsbf02.news.aol.com> Cecil Moore wrote: > >It follows that if two sub-atomic particles can communicate with >each other instantaneously no matter what distance is between them, >then our "reality" does not originate locally. > >Since space itself is curved, how do you propose to prove a line >is straight? Your ruler isn't even straight. > >Don't look now, but Newton's Laws have a built in error. As a matter >of fact, every time you make a measurement, you make an error. > All those statements may well be correct. But in everyday life - including electronics and radio engineering - those effects are totally negligible. At the beginning of this century it would have been quite reasonable to "believe in" simple physical laws - Newton, Maxwell etc. That is no longer reasonable because we now know that they break down at the very large (astronomical) or very small (atomic) scales. Instead we have to create an imaginary ring-fence around our everyday experience. "In Here", the old laws still apply; straight lines are straight, and the length of a ruler doesn't vary if you look harder at it. Maxwell's equations work In Here, just as well as they always did, and so too do Newton's Laws and the laws of Thermodynamics. "Out There", none of that may be true; but In Here it doesn't matter. I think it's important to remember that this is an In Here newsgroup. Antennas don't come anywhere near the ring-fence. They are complicated and sometimes difficult to understand, but that's something different. So if we still can't explain every single aspect of our antennas, let's not blame Maxwell, Kirchhoff or Ampere. It's strictly our problem. 73 from Ian G3SEK Editor, 'The VHF/UHF DX Book' 'In Practice' columnist for RadCom (RSGB) Professionally: IFW Technical Services Clear technical English - anywhere. From amsoft@epix.net Fri May 03 12:10:29 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: 1 May 1996 23:04:08 GMT Message-ID: <4m8ql8$240@itnews.sc.intel.com> References: <4lno77$f3e@news7.erols.com> <4m4gqd$hce@crash.microserve.net> <4m52gd$qm1@hobbes.cc.uga.edu> ignacy@num.ads.uga.edu (Ignacy Misztal) wrote: >I agree that the impedance variations can be extreme, but they are not >unmanageable. > >Ignacy Misztal Ham radio: NO9E, SP8FWB Hi Ignacy, and now the $64 question (I'm old enough to remember the $64 question on AM radio). Do you know what your impedance variations are? If not, how can you possibly know if you have managed them properly? I was losing half my power on 75m. I was still "getting out" and "having fun". It is possible to get lucky and achieve a good match by accident without knowing anything or measuring anything, but not very likely. The impedance at your balun is easy to measure using a $13 Ladder-Lizard from TechnoLogic Concepts and IMO is well worth knowing for sure. 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Fri May 03 12:10:30 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: 1 May 1996 14:39:33 GMT Message-ID: <4m7t36$sbm@itnews.sc.intel.com> References: <4lgmjn$ecm@crash.microserve.net> <4lm11v$9vt@crash.microserve.net> <4lmtc3$524@nnrp1.news.primenet.com> <4m4glj$hce@crash.microserve.net> jackl@pinetree.microserve.com (WB3U) wrote: >Louis Varney has already laid claim to >102', so maybe you should try, say, 84' and see what happens. ;) I personally like the 20m EDZ length of 88' for an all-band HF antenna. I've been concentrating on 102' because it is so popular. 88, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Fri May 03 12:10:32 1996 From: Gary Cavie Newsgroups: rec.radio.amateur.antenna Subject: Re: Formula For J-Poles Date: Tue, 30 Apr 1996 22:40:40 +0100 Message-ID: <318688D8.169C@dircon.co.uk> References: <31863F07.2BE9@azstarnet.com> Buster wrote: > > Any one have formula's for J-Pole construction. > > I have plenty of dimensions, just want the raw formula's for > future reference > > How to calculate the radiator & matching stub lengths. > > Most importantly, how to calculate where to feed the antenna > from the short at the bottom? > > What I'm looking to do is build J-poles for different bands, and > possibly out of materials with different velocity factors. My big > hurry up project is a 6m Twin-Lead J-Pole. It'd be great for field > day. Just toss one end up in the tree. > > I have plenty of construction articles on J-Poles, unfortunately > they don't tell you how they came up with the numbers. They just > say measure, cut, solder. > > Thanks > > Buster, KC7KMJ, DM42 > Tucson, AZ Whilst on the subject of J-poles, can anyone give me the dimensions for a J-pole centred on 145.500 MHz, made from 15mm copper pipe and yorkshire fittings. I know there was a design for it in the September 1994 issue of Practical Wireless, but this is the one copy which appears to have gone missing from my file. Many thanks Gary, G7SJF Tiptree, England quacker@dircon.co.uk From amsoft@epix.net Fri May 03 12:10:33 1996 From: snowak@uniserve.com (Stan Nowak) Newsgroups: rec.radio.amateur.antenna Subject: High gain antenna for cellular phone Date: 1 May 1996 00:16:08 GMT Distribution: world Message-ID: <4m6ag8$r78@atlas.uniserve.com> I need a high gain yagi antenna for the cell phone band. If any one knows who make one I would appreciate the info :) Brad - ve7qbn From amsoft@epix.net Fri May 03 12:10:34 1996 From: wa6awd@wolfenet.com (Alan Burgstahler) Newsgroups: rec.radio.amateur.antenna Subject: Re: High gain antenna for cellular phone Date: Wed, 01 May 1996 13:57:03 GMT Message-ID: <4m7qja$nnp@ratty.wolfe.net> References: <4m6ag8$r78@atlas.uniserve.com> snowak@uniserve.com (Stan Nowak) wrote: >I need a high gain yagi antenna for the cell phone band. If any one knows >who make one I would appreciate the info :) They're commerciall available. At work we've bought some from Tessco, which is a two-way radio supplies supplier, however I don't remember the brands of t he yagis. Tessco can be found at http://www.tessco.com. No connection to me except at work we're a satisfied customer. Alan Burgstahler - WA6AWD - Kent, WA, USA From amsoft@epix.net Fri May 03 12:10:35 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Modeling a ferrite bead in Eznec Date: Wed, 01 May 96 16:31:19 GMT Message-ID: <4m83ik$872@nadine.teleport.com> References: <3186DE31.191A@interaccess.com> In article <3186DE31.191A@interaccess.com>, Robert Mansfield wrote: >Hi to all > >I need info on how to model a clip on ferrite bead(s) on a guy wire (the >backstay on my sailboat) in Eznec. I want to try some antenna experments, >but I need to breakup the guy wire resonance on 20 meters. I want to test >this in Eznec first since I can only put the beads on when I have the mast >stepped which is once a year. Thanks in advance. > >Bob Mansfield >WA8USR >s/v Shadow Dancer It would be modeled as a "load". You'll either have to measure the bead's impedance or get its impedance at the frequency of operation from the bead's manufacturer. The impedance could be primarily inductive, primarily resistive, or in between, depending on the frequency and type of ferrite. Roy Lewallen, W7EL From amsoft@epix.net Fri May 03 12:10:35 1996 From: "Clark A. Townsend" Newsgroups: rec.radio.amateur.antenna Subject: TA-33Jr Antenna Date: Wed, 01 May 1996 13:52:27 -0700 Message-ID: <3187CF0B.1796@richnet.net> The wind surface area is 5.7 sq. ft. according to Mosley catalog Clark, K8CZM From amsoft@epix.net Fri May 03 12:10:36 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: The Coax Mentality Date: 30 Apr 1996 23:05:02 -0700 Message-ID: <4m6uue$920@nnrp1.news.primenet.com> References: <4m0rpa$ore@chnews.ch.intel.com> <4m4gon$hce@crash.microserve.net> jackl@pinetree.microserve.com (WB3U) wrote: > cmoore@vegas.ch.intel.com (Cecil A. Moore~) wrote: >>Ladder-Line Mentality: It's easy to make measurements >>along a transmission line without disturbing anything. >How long does this take? It takes a leisurely hour per band. All you do is find a current maximum and a current minimum. Dividing those two readings gives you the SWR which you can draw as a circle on a Smith chart. The current maximum is the low purely resistive point and the current minimum is the high purely resistive point on that very same SWR circle. Since it's a halfwavelength around the Smith chart and you know the length of your ladder-line, you know the antenna impedance and the impedance at the transmitter. >That means it requires (ugh) math. Tell me again, where do I get one >of those coax meters? Sorry, it doesn't work on coax which is good enough reason not to use it. A voltmeter and a calculator is all you need in addition to the Ladder-Lizard from TechnoLogic Concepts, tlcdhconsult@delphi.com My application note avoids Smith charts altogether relying instead on tables. >>Ladder-Line Mentality: Cutting and trying is inexpensive >>and easy. It as easy as twist-ties. Splicing is as easy >>as using butt lug connectors. >This could get expensive around the ten-thousandth splice. I have only two splices in 72 ft of ladder-line and they happened before I knew what I was doing. >McCoy says the best length is the one that reaches from the antenna to >the shack. What impedance is that? Sorry to say, Lew is one of the nicest guys I know but he is wrong on that one. A random length of feedline is almost never the best. If you locate a current node, a 50 ohm point is always less than 0.013 wavelength away for any 300 ohm ladder-line SWR over 6:1. >I like this idea. What happens when you use a 0 pF cap like the >other guy was asking about? Jack, I just tried a 0 pf cap and nothing happened. I think I'll ask for my money back if I can find it. :-) 73, Cecil, KG7BK, OOTC From amsoft@epix.net Fri May 03 12:10:37 1996 From: clarke@acme.ist.ucf.edu (Thomas Clarke) Newsgroups: rec.radio.amateur.antenna Subject: Vertical Zepp? Date: 1 May 1996 18:44:25 GMT Message-ID: <4m8be9$8os@news.cc.ucf.edu> Reply-To: clarke@acme.ist.ucf.edu I've been thinking about the advantages of a vertical, but the problem of a good ground system seemed insurountable. Then I thought of trying something like a vertical zepp. End feed a vertical 1/2 wave dipole with open wire line. I think this would work without a ground system. I've even been thinking about supporting a thin wire with a balloon or a kite to get 80m or even 160m coverage without a tall tower. Has this been tried? Is there a catch 22? I can't find anything like it in the ARRL antenna book. Thanks. Tom Clarke KE4VFH From amsoft@epix.net Fri May 03 12:10:38 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: Vertical Zepp? Date: 2 May 1996 18:44:04 GMT Message-ID: <4mavpk$1dd@news.asu.edu> Tom Clarkewrote - Then I thought of trying something like a vertical zepp. End feed a vertical 1/2 wave dipole with open wire line. I think this would work without a ground system. I've even been thinking about supporting a thin wire with a balloon or a kite to get 80m or even 160m coverage without a tall tower. My recent posting in reply assumed Tom was going to ground one side of the balanced line at the anttenna. I now think Tom was proposing hoisting the antenna AND feed line so as to be a sort of inverted true Zepp. Tom, As with almost any unbalanced load, there will be some radiation from the open wire balanced feed line. However I should expect it to be less than that when a hrizontal half wave is end fed by open wire feeders because in this case the feeders are roughly in line with the antenna instead of perpendicular to it. So there is less coupling between the antenna and the line. You did not propose a specific line length. It appears that the height of the antenna will be determined by the line length. You shoud investigate the resulting pattern since it changes with antenna height There will also be some deviation from the pattern caused by the radiation from the feed line as mentioned above. Charlie, W7XC -- From amsoft@epix.net Sat May 04 15:45:04 1996 From: hannu.forsstrom@valmet.com Newsgroups: rec.radio.amateur.antenna Subject: 2m/70cm base station antenna Date: Fri, 03 May 1996 13:07:11 -0700 Message-ID: <318A676F.4724@valmet.com> Hi, I have tried to find an article with information about building a 70cm/2m base station gp-antenna. What I am after is an omnidirectional system with a considerable gain over 1/4lambda gp and that needs only one coax. Diamond has many different models on market but how to build one yourself? Anyone can help me with this? Hannu/OH6MAZ hannu.forsstrom@valmet.com From amsoft@epix.net Sat May 04 15:45:05 1996 From: tomb@lsid.hp.com (Tom Bruhns) Newsgroups: rec.radio.amateur.antenna Subject: Re: Electric half-wavelenght xmition lines... Date: 3 May 1996 17:10:17 GMT Message-ID: <4mdelp$ssm@hpcvsnz.cv.hp.com> References: <24523@SP-gw.ampr.org> py3crx@sp-gw.py2bjo.ampr.ORG wrote: : Hi all: : Some days ago I'd posted a msg. asking if it's valid take antenna : measurements (HF range) using a RX Noise Bridge conectet to a antenna : trhu a electric half-wavelenght transmition line. : This particular line lenght (and it's multiples) will be "transparent" to : complex impedances? If the line has zero loss, then the impedance at one end of a half-wave piece of line will be exactly reflected to the other end. If you want to take into account line loss, you can use standard line formulas. The result of loss is always that the impedance seen at the transmitter end of the n*half-wavelength line will be the same phase angle as the load but of a magnitude (slightly) closer to the line impedance. Think of a Smith chart. A half wavelength along lossless line runs you around one full circle, centered on the line impedance normalized to the center of the chart. If the line has loss, the path becomes a spiral, in toward the center as you move away from the load, but still a full 360 degrees for 1/2 wavelength along the line. -- Cheers, Tom tomb@lsid.hp.com From amsoft@epix.net Sat May 04 15:45:06 1996 From: dmitchel@david.mitchell@adobe.com (David Mitchell) Newsgroups: rec.radio.amateur.antenna Subject: Re: Ethernet Cable Date: 3 May 1996 15:56:58 GMT Message-ID: <4mdaca$inr@enquirer.mv.us.adobe.com> References: <0000121B00000B93@prostar.com> Cougercat (cougercat@prostar.com) wrote: : I have heard that Ethernet cable makes good transmitting coax. What is the : impedance of the Ethernet cable (the orange stuff) and how much power can : it handle? : Thanks : Please reply to : : cougercat@prostar.com : Jeff The impedence of Ethernet coax is 52 ohms and the thick stuff (orange or yellow) can handle the legal limit. It gets lossy in the VHF and UHF bands despite the foam dialectric and double shield, and the outer sheath will deteriorate when exposed to sunlight. Beware of used Thicknet cable, as it may have "vampire tap" holes in it. These let in moisture, small insects, etc. and can make impedence matching a real challenge. Saludos, .david. -- David Mitchell Adobe Systems Incorporated david.mitchell@adobe.com Bainbridge Ometepe Sister Islands Association davidm@bosia.org Amateur Radio AB7DM & YN5NPM davidm@ab7dm.ampr.org *Organic, Shade-grown Fair-traded Coffee at http://www.bosia.org* From amsoft@epix.net Sat May 04 15:45:07 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: Modeling a ferrite bead in Eznec Date: 1 May 1996 08:49:49 -0400 Message-ID: <4m7mld$cb5@newsbf02.news.aol.com> References: <3186DE31.191A@interaccess.com> In article <3186DE31.191A@interaccess.com>, Robert Mansfield writes: >Hi to all > >I need info on how to model a clip on ferrite bead(s) on a guy wire (the >backstay on my sailboat) in Eznec. I want to try some antenna experments, >but I need to breakup the guy wire resonance on 20 meters. I want to test >this in Eznec first since I can only put the beads on when I have the mast >stepped which is once a year. Thanks in advance. > >Bob Mansfield >WA8USR I would insert a load at the point in question that has the correct series resistance and inductance for the bead and frequency you are using. The resistance and inductive values vary with frequency (and can even go capacitive). I have measured and logged the data from dozens of common beads. I'm not sure the manufacturers aways have that data available, but you can try them. 73 Tom From amsoft@epix.net Sat May 04 15:45:08 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Problems modelling linearly loaded dipole & beam! Date: Thu, 02 May 96 22:59:27 GMT Message-ID: <4mbema$gnn@nadine.teleport.com> References: <4lgn5r$nki@adams.wwc.edu> In article <4lgn5r$nki@adams.wwc.edu>, frohro@wwc.edu (Rob Frohne) wrote: >I have been trying to model KLM's linearly loaded rotatable dipole. I found the impedance >to match just fine experimentally, but I can't seem to make the simulation agree. I'm >using NEC2 and I've used up to 350 elements for just this dipole. The resonance doesn't >seem to occur at the right place. If I use around 50 elements the reactance is about 10% >more negative (from -180 ohms to -200 ohms); the resistance seems to have converged to about >what I expect. Has anyone else had any experience with modelling linear loaded antennas. I'm not familiar with the particular antenna, but if the entire antenna isn't made from wire or tubing of one diameter, NEC-2 won't give completely accurate results. The error will manifest itself chiefly as an inaccurate reactance. This is a known shortcoming of NEC-2. For best accuracy with differing-diameter conductors, make the segment length as LONG as possible. This is contrary to intuition, but the problem is aggravated by short segment length-to-diameter ratios near the junctions of dissimilar-diameter wires. The error is large enough to throw the pattern (particularly the nulls) badly off if parasitic elements have wires of more than one diameter. EZNEC and NEC-Wires have a built-in correction for some special cases, such as full-length Yagi elements, using an equivalent single-diameter conductor based on a method in Dave Leeson's book _Physical Design of Yagi Antennas_. However, it's valid only for straight elements with a length near 1/2 wavelength, such an in full-size Yagis, and not for "linearly loaded" elements. Roy Lewallen, W7EL From amsoft@epix.net Sat May 04 15:45:10 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: Radiation resistance Date: 3 May 1996 18:49:40 GMT Message-ID: <4mdkg4$hu1@news.asu.edu> Richard, Here is a fairly simple approximation of Rr seen at the center feedpoint of a horizontal dipole (possibly either not loaded, inductively loaded at any point or end capacity loaded; in freespace and assuming sinusoidal current distribution. This Rr will vary with height above earth on a curve of Rr vs height oscillating about the free space value as a damped sinusoid approaching the free space value at great heights and decreasing with height below about .2 wavelength height to some small value at zero height. Note: Rr does NOT include earth loss, copper loss of the wire or loss resistance of any loading coils. Earth loss is generally negligible at heights above about .2 wavelengths. Rr = 70 (sin L1 + cosL1(1 - cosL2)/sinL2)) ^2 Where: L1 = angular length of section below loading coil L2 = angular length of section above loading coil. angular length = .366 h f Where h = length in feet of each side of the dipole and f = frequency in MHz. This equation applies to any loading coil position including loading at the feedpoint (L1 = 0) and purely capacitive end loading where L2 = 0. Coil loss resistance reflected to the feedpoint will be approximately Rc cos^2 L1 Where Rc is the loss resistance of the coil. But because the current distribution is not quite sinusoidal, the actual value will be somewhat greater. This loss resistance from copper loss of the antenna wire (usually negligible for otherwise high efficiency very short antennas), coil loss and earth loss a r to form the input impedance of the antenna center feedpoint. Charlie, W7XC -- From amsoft@epix.net Sat May 04 15:45:11 1996 From: "Thomas W. Castle" Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.equipment Subject: Sale Date: Fri, 3 May 1996 01:52:58 -0400 Message-ID: Reply-To: "Thomas W. Castle" Hi Tom here... I have for sale 2 Regency 16ch programable mobiles. They have 30W output, keyboard programable, mobile mtg brackets, power cords, mics & all paperwork... They have programming switch added to back of radio for on the fly re-programming. They have been set-up for Emergency service rigs 140Mhz - 180Mhz. broad banded, running 25W at the moment, an working in the 2 mtr band. Type Accepted... So should be usable in other services as well. They have scan, priority, skip, monitor & Tx & Rx pls built in. It can have 2 different PL's <1 tx & 1 rx>... Still with their original boxes, never pressed into service... Tested to check functions on 2 mtrs... Area has gone 800Mhz trunked... Will sell one or both, $235.00 each shipped.... Both for $450.00... Contact me via e-mail or thru packet KD4QHH@K4DPZ.#Gnsvl.Fl.USA.NA. Tnx De Tom 73 From amsoft@epix.net Sat May 04 15:45:12 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: The Coax Mentality Date: 2 May 1996 18:39:04 GMT Message-ID: <4mavg8$g1i@itnews.sc.intel.com> References: <4m8ehm$m2a@itnews.sc.intel.com> <4m8usl$5mt@hpcvsnz.cv.hp.com> tomb@lsid.hp.com (Tom Bruhns) wrote: >you can probe the voltage in a coaxial line by inserting detectors at >intervals along the line. You don't need a lot of them; four at fixed >locations, a known propagation time apart, should be plenty. If you choose >the separations correctly, the four should cover the whole HF part of the >spectrum. You can use a computer to measure the voltages and calculate the >same sorts of things you are suggesting for open wire line. Hi Tom, sounds messy compared to absolute non-intrusion into the ladder- line. Inductive coupling is all that is needed for ladder-line measurements. It would be interesting to hear from anyone who has done the above with coax and/or are willing to try it in the future. >I think there continue to be appropriate places to use coax, and >appropriate places to use balanced lines. I appreciate your food for >thought, but it's not going to make me go out and replace the >coax feeding my unbalanced antennas that already match the 50 ohm line >quite well. And I don't think you were suggesting that anyway. I'm not anti-coax. It's great for 50 ohm unbalanced antennas and mobile stuff. My remarks are aimed at HF hams who already use ladder-line but don't know how to make very simple measurements in order to know everything about their antenna system. I'm designing a remote control for a non-resonant ladder-line fed dipole here at Intel because the 70 ft of transmission line between the roof and the shack needs to be coax. The remote controller will ensure a perfect 50 ohm match into the coax. 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Sat May 04 15:45:14 1996 From: P Tyers Newsgroups: rec.radio.amateur.antenna Subject: Re: Two beams on one feedline ? Date: Fri, 03 May 1996 16:11:43 +1100 Message-ID: <3189958F.2C27@trl.oz.au> References: <4lm0n3$5mv@gateway.grumman.com> <4lr1vq$2n24@info4.rus.uni-stuttgart.de> <4mb3hj$b2p@news.service.uci.edu> Brian Williams wrote: > > In article <4lr1vq$2n24@info4.rus.uni-stuttgart.de>, > moritz@ipers1.e-technik.uni-stuttgart.de says... > > >In article <4lm0n3$5mv@gateway.grumman.com>, > >Pat Masterson wrote: > > >> I want to use two 440 beams to link two packet nodes. All > ~~~~~~~~~~~~~ ~~~ ~~~~~ > >>that is available to me are standard, 50 ohm antennas. How > >>can I connect them to one radio, presenting a decent > ~~~~~~~~~ > >>impedance load? Is there a trick with matching sections of > >>coax I can use? Thanks. -pat > I believe he's looking for the proper way to take both beams (pointed > in two directions for covering two different areas (beams between those > two areas) and using one radio, not two. > > I think that > using a length of 50 ohm coax from the radio to a T-coupler and using > two equal lengths (maybe not critical if antennas are pointing in > seperate directions) of 75 ohm coax between the other two connectors of > the coupler to the antennas. Almost right! Use two lengths of 75 ohm coax which are ODD (1,3,5 etc)quarter wave multiples (remember the velocity factor - roughly 0.66 - when calculating the quarter wavelengths). These act as transformers 50 ohms to 100 ohms and by paralleling the 100 ohm impedances the radio sees 50 ohms again. Generally the arrangement for stacking is half wave vertical of horizontal seperation and one quarter wave plus one three quarter wave cable section. For pointing in two directions I'd assume any mixture of odd quarter wave sections would do. But dont ask me what the resultant pattern would look like !! -- P Tyers, Tel. +61-(0)3-92536794 AARnet: p.tyers@trl.telstra.com.au CSnet: p.tyers@trl.oz.au HAM: VK3KTS MAIL: Telstra Research Laboratories,P.O. Box 249, Clayton,VICTORIA 3168,AUSTRALIA From amsoft@epix.net Sat May 04 15:45:15 1996 From: "George J. Molnar" Newsgroups: rec.radio.amateur.antenna Subject: Re: Want to know differenses between SB200 and SB201 ?? Date: Fri, 03 May 1996 18:29:18 -0600 Message-ID: <318AA4DE.724C@interealm.com> References: <4m7efv$2dp@mn5.swip.net> Reply-To: gmolnar@interealm.com To: Martin Rask Martin Rask wrote: > > Could anyone tell med the differenses between Heathkit SB200 amp and the > Heathkit SB201 ??? > The 201 didn't have 10m coverage as sold by Heathkit. The 200 did. I suspect most 201's in the field today have been modified "back" into 200's, though. -- George J. Molnar Highlands Ranch, Colorado Amateur Radio: KF2T@N0QCU.#NECO.CO.USA.NOAM http://www.interealm.com/p/gmolnar/index.html From amsoft@epix.net Sat May 04 15:45:25 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.homebrew Subject: Re: Grid Driven 4-1000 Date: 3 May 1996 13:12:40 -0400 Message-ID: <4mdeq8$bhv@newsbf02.news.aol.com> References: <4mccop$1ao@chile.lascruces.com> Hi All, The correct AB1 formula for a simple shunt grid resistance is: R= Eg^2 / 2Pdrv A 50 ohm L pad can be calculated using ohm's law: .707bias / sqrt(p/50) = Rgrid. The input series R would of course be: 50 - Rgrid = Rs With 90 watts and 56 volts of bias, 30 ohms of grid-cathode shunt resistance fed by a series 20 ohm resistor would provide both proper grid resistance and exciter loading. Years ago I ran a pair of grid driven 4-1000A tubes, but scrapped the idea because of tuning and adjustment difficulties. AB1 grid driven amplifiers are tough to tune correctly, even the slightest amount of grid current or improper loading makes them poor IMD performers. I eventually tried to run the 4-1000A's in the Collins circuit used in the 30L1, but was unsucessful due to less than sufficient catode to anode shielding. The only circuit that worked well was conventional grounded grid with screen and grid bias applied. There was some slight performance improvement over no screen or grid bias in grounded grid. As with any tetrode, screen regulation and grid current in both grids was critical. As time passed I scrapped the 4-1000's in favor of a grounded grid triode. IMD performance and ease of adjustment improved greatly with this move. Looking back on it all, there was almost no advantage for all the effort in building the screen and bias supply in the cathode driven 4-1000 configuration, althought it was easy to use and relatively clean even when slightly mistuned. The thing I wanted awas more power gain, but gain barely increased over a conventional grounded grid circuit with no screen or grid bias voltages. The grid driven configuration gave greatly improved power gain, but was pretty fussy to tune properly on SSB. The largest problem was creation of IMD even when scope and meters appeared correct. I think the Collins circuit (used in the 30S1 4CX1000 amp) would have been the best circuit but the poor screen grid shielding in the 4-1000A's made regeneration a problem. There are pros and cons to every circuit, and I guess the best choice depends on user goals. But the 4-1000A is a far cry from the 4CX1000 in operation and stability. 73 Tom From amsoft@epix.net Sat May 04 15:45:26 1996 From: py3crx@sp-gw.py2bjo.ampr.ORG Newsgroups: rec.radio.amateur.homebrew Subject: Information Needed! Date: 3 May 96 02:39:58 GMT Message-ID: <24501@SP-gw.ampr.org> Hi all. I still looking for information at the following items: - CELLULAR PHONE PWR MODULE, LABELED FMC080802-20, REMOVED FROM A NEC CELL-PHONE. - 2SC1251, A NEC TRANSISTOR (SUPOSE TO BE A CLASS A UHF DRIVER, I THINK I SAW IT AT SOME MOTOROLLA DATABOOK SOME YR AGO) - IF THERE IS ANY CODE TO SMD TRANSISTOR AND DIODES/MIXERS SIMILLAR TO THE ONE WE USE TO SMD (CAPACITORR AND RESISTORS). - ANY SOURCE FOR SAW-FILTERS, 455KHZ OR 10.7MHZ, 40khz BW(NOAA/GOES/ METEOSAT DEVIATION). - HRPT INFORMATION/SOFTWARE SOURCES. - PATCH ANTENNAS THEORY (AND THEIRS YAGI-LIKE ASSEMBLY, SUCH AS USED TO MMDS LNBY COMBINATION) AND MORE: - ANY RESULTS USING STANDARD TVRO KU-BAND FEEDERS AT 10.25GHz ASSOCIATED TO THOSE 0.6...2.4 METER DISHES(0,33...0.36 F/D)? - HOME-MADE FERRITE CIRCULATOR TO IN A 10.25GHz WAVEGUIDE: TO ALLOW MO- DIFIED KU-BAND LNB AND GUNNPLEXER CONECTION(DUAL-PORT...)? - ANY SUGESTION TO BUILD A 1.2/2.4GHz DIRECTIONAL COUPLERS, STRIP-LINE ON PCB + SMA CONN + SMD BALANCE RESISTORS (-20...-30dB COUPLING FACTOR)? MAY BE A MODEL 43 PLUS THE CORRECT PLUG-IN DETECTORS...BUT HERE? THE DETECTOR WILL BE A TEKTRONIX 2714 SPECTRUM ANALYZER! THANKS IN ADVANCE! 73 - Marcus Ramos - PY3CRX@SP-GW.AMPR.ORG - Sao Paulo - Brasil From amsoft@epix.net Sat May 04 15:45:27 1996 From: rmd@ka4ybr.netmha.com (Bob Duckworth) Newsgroups: rec.radio.amateur.homebrew Subject: Re: Need Phone In-Use Light Date: 2 May 1996 16:01:17 -0400 Message-ID: <4mb4ad$76s@ka4ybr.netmha.com> References: <8BF528A.0028001B54.uuout@hobbs.com> In article , wrote: > >In Article<8BF528A.0028001B54.uuout@hobbs.com>, >writes: > > > Does anyone a nifty circuit for a phone in-use indicator. The >indicator > > >JADE Electronics makes one just as you described. Its a kit >for $11.00. A bit expensive but you only need to buy one >and clone the rest... >73 >Scott > Or you can put a diac in each line. If one phone is off hook, there won't be enough voltage to turn on the diacs at the other phones on. The end result being that you can only use one phone at a time. -bob -- Bob Duckworth Consulting, 960 Ralph McGill Blvd. Atlanta GA 30306-4447 bobs' address is rmd@ka4ybr.netmha.com 404-888-0389(V) 892-2301(FAX) Buy Sell Trade Surplus Computer Electronics Datacom Telecom since 1981. Fax or email your list for a fast cash offer. Watch for listserv catalog. From amsoft@epix.net Sat May 04 15:45:28 1996 Newsgroups: rec.radio.amateur.homebrew From: midgard@nycmetro.com (SARUMAN) Subject: Schematic for DTMF decoder Message-ID: <457.6697T1137T2403@nycmetro.com> Date: Sat, 4 May 1996 00:05:15 GMT Hi all, anyone have a schematic for a DTMF decoder? I'm looking for something with a LCD display to Translate and show DTMF's. Thanx Midgard Graphics 3D Animation and Special FX for the hobbyist videographer Email: midgard@nycmetro.com -- Drop into #amigacafe on IRC's undernet for a chat sometime -- A man of many hobby's master of none. From amsoft@epix.net Sat May 04 15:45:29 1996 From: redbone@juno.COM (Douglas R Davis) Newsgroups: rec.radio.amateur.homebrew Subject: Some Antenna Trim Caps Date: 3 May 96 07:09:36 GMT Message-ID: <19960503.020937.7791.0.redbone@juno.com> References: <199605022208.PAA00652@mail.ucsd.edu> Antenna Trim Caps 10-90pF, 50V trim cap used to match antennas in auto radios, CB'ss, transceivers, etc., 15/16" tall X 1/2" wide with a 6-32 mounting hole. Stock# 0823-VC, 4?$1.00 Marlin P. Jones P O Box 12685 Lake Park FL 33403-0685 407-848-8236 Order FAX 1-800-4 FAX YES From amsoft@epix.net Tue May 07 19:37:03 1996 From: "Don P. Wittlich" Newsgroups: rec.radio.amateur.antenna Subject: (no subject) Date: Mon, 29 Apr 1996 19:29:03 -0700 Message-ID: <31857AEF.2E62@apci.net> subscribe From amsoft@epix.net Tue May 07 19:37:04 1996 From: markm@kdcol.com (Mark Moulding) Newsgroups: rec.radio.amateur.antenna Subject: Ant Element Keepers - Need Source Date: Mon, 06 May 1996 04:12:03 GMT Message-ID: <4mju2n$as9@kdcol.kdcol.com> Reply-To: markm@kdcol.com I decided to do a mod to a 432 Mhz antenna and find that I am going to need to replace the element keepers as well! These are the type used by cushcraft and M2, I think. For 3/16th dia elements. Anyone know a good source for these? Thanks, 73, Mark, KE7NS From amsoft@epix.net Tue May 07 19:37:05 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: antenna impedance bridge wanted!!! Date: 5 May 1996 18:27:02 -0700 Message-ID: <4mjkh6$6na@nnrp1.news.primenet.com> References: <4mfn08$g51@everest.vol.it> pgram@mbox.vol.it wrote: >Does anybody know where can I find an Antenna Bridge If you can use ladder-line, your antenna bridge will cost almost nothing. Email me for details. 73, Cecil, KG&BK (W6RCA soon), OOTC From amsoft@epix.net Tue May 07 19:37:06 1996 From: ddeming@geophysics.scif.uoknor.edu (D. Deming) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Question Date: Mon, 06 May 1996 09:40:00 -0400 Message-ID: References: In article , ddeming@geophysics.scif.uoknor.edu (D. Deming) wrote: > I know this newsgroup is for RADIO, but maybe someone can help > me with this question. > > I have what appears to be a VHF antenna on the roof of my house > left by the previous owner. Works great, but absolutely no > UHF reception. > Thanks to everyone who helped me on this question. However, the problem turned out to be my own stupidity. After some more testing, the problem appeared to be confined to our 2 modern Sony tvs. The antenna worked greate with my 30-year-old Sony. I called Sony and they reminded me to turn off the "cable" switch. I did, and now everything works. Thanks again. From amsoft@epix.net Tue May 07 19:37:07 1996 From: postar@voicenet.com (Edward French) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Theory Question Date: Sat, 04 May 1996 09:28:06 -0500 Distribution: world Message-ID: References: <19960430.115154.04@southlin.demon.co.uk> > Maxwell is deservedly honoured for providing us a calculating engine that > correctly models real observations in electromagnetics. That we users of > his work have neglected to re-jig or replace the concepts to provide a > consistent model, is a sad admission that maybe we have not the ability. > > out there to whom Maxwell might even have invited out for an evening > intellectual jam session. Maybe if I lurk this group long enough.... > > Thanks in advance for allowing this mischief. > Hmm.. I just *know* you are going to make me regret it. > > 73's + Regards to all > > G4WNT > > -- > Graham Seale graham, how did mr.maxwell live?...what's earliest record of vector math concept? thanks and take care -- hug the day From amsoft@epix.net Tue May 07 19:37:08 1996 From: marktaint@aol.com (MARKTAINT) Newsgroups: rec.radio.amateur.antenna Subject: Re: Any opinions on 2-Element "Butterfly" Beam antenna? Date: 5 May 1996 23:24:43 -0400 Message-ID: <4mjrdr$d7s@newsbf02.news.aol.com> References: <318690DE.41C67EA6@eecs.berkeley.edu> Reply-To: marktaint@aol.com (MARKTAINT) I had the Butternut Butterfly beam antenna up for about two years until I moved. I only had it up about 25 feet and only ran it barefoot so it wasn't perhaps a true picture of what the antenna is capable of. I had/have mixed feelings about the antenna. On the one hand, I was able to make a number of DX contacts to various parts of the world with it and having the five band capability is very nice. On the other hand, I had hoped to make contacts with my brother-in-law in Papua New Guinea and was never really able to do that with him. I was able to make some contacts into VK and ZL land though so I'm not sure the difference . Perhaps he was in a more difficult area to reach. I found it to be a fairly difficult antenna to assemble and tune as well. It was definately *not* one where you put color coded screws in the slots and that's it. I couldn't confirm the gain figures quoted by the company and I also couldn't tell you whether a vertical would be better. Like I said, I have mixed feelings about the antenna. If you're looking for a small, easy to turn antenna, with 5 band capability, the Butternut could work very well for you. If you're looking to be able to work lots of DX, then you might not be very happy with it. From amsoft@epix.net Tue May 07 19:37:10 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: 4 May 1996 19:42:01 -0700 Message-ID: <4mh4hp$5fg@nnrp1.news.primenet.com> References: <4mf19i$lu9@news.asu.edu> hamop@aztec.asu.edu (CHARLES J. MICHAELS) wrote: >Cecil, > Correction on previous posting (Ooops, used .2 dB per 100 >feet ) > A 40 meter dipole of 66.45 feet of #12 copper wire >(resonant at 7.15 MHz) 40 feet above medium quality earth has an >input impedance of 1.694 - j 2354.8 at 1.9 MHz according to >EZNEC. > If fed by 100 feet of 450 ohm open wire line having the >suggested attenuation factor of .02 dB per 100 feet, the line loss will >be about 5.86 dB which means that 17.06% of the power input to >the line reaches the antenna. Hardly MOST. Charlie is having trouble with his newsreader and sent me an email to point out my fuzzy logic. I was assuming that 50 ft of line had half the loss of 100 ft of line. That's only true with matched-line losses. When reflections are present, 50 ft of line has more losses than 100 ft of line. Thanks Charlie, for setting me straight. However, I know a way around the problem. If the second 50 ft has less losses than the first 50 ft, just use the second 50 ft instead of the first 50 ft. :-) 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Tue May 07 19:37:10 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: 5 May 1996 18:02:01 GMT Message-ID: <4miqep$i6i@news.asu.edu> Cecil said - Hi Ignacy, I can tell you're not a purist. :-) What you may not realize (QST may not realize it either) is that it is possible to radiate most of your 160M power from a 40m dipole if you get your transmission line losses low enough. If you use open- wire transmission line, the matched-line loss is about 0.02 dB per 100 ft on 160m. You can stand a gigantic SWR before you lose "most" of your power in the open-wire line. Notice, I said open-wire rather than ladder-line. 73, Cecil, KG7BK (W6RCA soon), OOTC Cecil, Correction on previous posting (Ooops, used .2 dB per 100 feet ) A 40 meter dipole of 66.45 feet of #12 copper wire (resonant at 7.15 MHz) 40 feet above medium quality earth has an input impedance of 1.694 - j 2354.8 at 1.9 MHz according to EZNEC. If fed by 100 feet of 450 ohm open wire line having the suggested attenuation factor of .02 dB per 100 feet, the line loss will be about 5.86 dB which means that 17.06% of the power input to the line reaches the antenna. Hardly MOST. Even with a 50 foot line, 5.35 dB or 29.17% at antenna. Charlie, W7XC -- From amsoft@epix.net Tue May 07 19:37:12 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: 5 May 1996 18:40:03 -0700 Message-ID: <4mjl9j$805@nnrp1.news.primenet.com> References: <4mf0ci$los@news.asu.edu> <4mhnqs$7tv@crash.microserve.net> jackl@pinetree.microserve.com (WB3U) wrote: >The dipole I'm using is much longer than that, but on various >bands I'm sure the SWR is at least as high as in the example. Hi Jack, don't assume that. Any center-fed longer than 3/8th wavelength will not get much above an SWR of 10:1 when fed with 450 ohm ladder-line. After all, 450x10=4500 ohms. However, when an antenna gets shorter and shorter down from 3/8th wavelength, the SWR goes up and up (to infinity with an iso- tropic. :-) First, find out what your SWR really is and then decide whether to worry about it or not. A 22:1 SWR with 450 ohm ladder-line can be around 10k ohms at the antenna. It's when the resistance doesn't go up with the reactance that you have to worry. That happens at less than 3/8th WL. In short, things go to heck at less than 3/8 wavelength on a center-fed. If you are longer than 3/8 WL, you probably don't have anything additional to worry about. I say "additional" because you worry too much already. :-) 73, Cecil, KG7BK (W6RCA soon) OOTC From amsoft@epix.net Tue May 07 19:37:13 1996 From: jim@inna.net Newsgroups: rec.radio.amateur.antenna Subject: Belden address Date: 6 May 1996 17:22:05 GMT Message-ID: <4mlcft$bka@tyger.inna.net> Reply-To: rmccarty@deltanet.com Western Regional Sales Office 2955 E. Main Street, Suite 300 Irvine, CA 92714 1-800-BELDEN-1 Jim@inna.net or HTTP://www.inna.net/Stevens From amsoft@epix.net Tue May 07 19:37:13 1996 From: chrisv@valteck.com (Chris Valliant) Newsgroups: rec.radio.amateur.antenna Subject: Best Antenna for Apartment ? Date: 6 May 1996 22:30:21 GMT Message-ID: <4mluht$q1i@news.inforamp.net> I live in a small apartment, but the landlord won't let me put an antenna on the roof. Does anyone know of a good antenna that I can mount on the window sill ? I have thought about putting up one without his knowledge, but that wouldn't be right. Any idea's would be greatly apreciated. Oh yea, this is for the 10 M band (forgot to add that in). Thanks in advance Chris From amsoft@epix.net Tue May 07 19:37:15 1996 From: "John D. Farr" Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Sun, 05 May 1996 02:26:11 -0500 Message-ID: <318C5813.34A4@ro.com> References: <4mg9ar$l77@crash.microserve.net> WB3U wrote: > > Lately, I've been thinking about stringing a wire vertical from > a tree and installing a good radial system underneath. However, > there's a wildlife problem that's threatening to thwart my plans. > > During the last two winters, I have been beseiged by an invasion > of moles. The runners they create in the yard and the many mole > hills make it impossible to consider radials. I still have to > cut what's left of the grass, and there's no question that the > moles' activity will push any wires I install up to the surface. > > So far I've tried the following with little or no success: > > Smoke bombs and poison pellets designed for this purpose > Traps designed to kill the mole when it tunnels underneath > Flooding the tunnels with a garden hose > Filling the tunnels with exhaust fumes from my car > 900 VAC at 1 Amp delivered into the ground by aluminum stakes > placed 20 feet apart > Elmer Fudd impressions (lawn chair and shotgun) > > The most successful was the AC votage. That seemed to drive them > away if I applied it intermittantly over a period of several days. > They always return quickly though, and for obvious reasons I can't > leave the current on indefinitely (or unattended). > > Does anyone know a solution for this problem? My last thought is > to try a much higher votage, but the current consumption of > continuously-applied AC becomes enormous above about 1 KV. If > I build a voltage tripler or quadrupler and use it to charge a > bank of capacitors, is there a way to discharge the caps into the > ground at timed intervals? Any other ideas? > > 73, > Jack WB3U I have a cat that has developed a taste for moles. I have no problems with them like some of my neighbors. Best of all, my cat brings me the best parts! 73, John From amsoft@epix.net Tue May 07 19:37:16 1996 From: bowman@montana.com (robert bowman) Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: 6 May 1996 00:05:00 GMT Message-ID: <4mjfnc$8d8@maw.montana.com> References: <4mg9ar$l77@crash.microserve.net> In article <4mg9ar$l77@crash.microserve.net>, jackl@pinetree.microserve.com (W B3U) says: >During the last two winters, I have been beseiged by an invasion >of moles. Does anyone know a solution for this problem? ferrets From amsoft@epix.net Tue May 07 19:37:17 1996 From: byoung@qni.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: 6 May 1996 18:16:11 GMT Message-ID: <4mlflb$rde@suba01.suba.com> References: <4mg9ar$l77@crash.microserve.net> Jack, I *HAD* a mole problem. I rectified it with several cheap battery-powered AM radios. #1 Tune them to a local rock station with a good signal. (needs to be rock-n-roll, moles like classical and country) #2 Turn 'em up fairly loud. #3 Stick 'em in heavy plastic bags. #4 Bury them where you have the problem. The batteries usually last a week or more, and by then the moles have "moved on" to greener pastures. Sounds silly, but it works! Bill Young byoung@qni.com KB0UZQ From amsoft@epix.net Tue May 07 19:37:18 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Sun, 05 May 96 20:10:13 GMT Message-ID: <4mj1t1$6rf@nadine.teleport.com> References: <4mg9ar$l77@crash.microserve.net> Get yourself an "Out-O-Sight" brand mole trap or clone. It's shaped like a couple of horseshoes spring-loaded together. I've used one for years, and trapped a couple of dozen moles with it. It has never failed to catch a mole. (Occasionally one will trip the trap without being caught but I get 'em eventually.) Roy Lewallen, W7EL From amsoft@epix.net Tue May 07 19:37:19 1996 From: Chuck Vaughn Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Mon, 06 May 1996 09:13:07 -0800 Message-ID: <318E3323.1B67@aa6g.org> References: <4mg9ar$l77@crash.microserve.net> WB3U wrote: > > Lately, I've been thinking about stringing a wire vertical from > a tree and installing a good radial system underneath. However, > there's a wildlife problem that's threatening to thwart my plans. > If you have enough vertical room you might consider a vertical dipole. I put together a 30/40m trapped one with capacitive hats that is only 35' long for a friend who had about 40' of vertical space. I've been surpised at how much DX he's been able to work, even on 40m. It's really a pretty good antenna for only a wire and no radials required! Chuck - AA6G From amsoft@epix.net Tue May 07 19:37:20 1996 From: Jake Brodsky Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: Sun, 05 May 1996 23:17:26 -0700 Message-ID: <318D9976.3D77@erols.com> References: <95849@gate.kc5aug.ampr.org> <4mg98q$l77@crash.microserve.net> WB3U wrote: > > aa5mt@gate.kc5aug.ampr.ORG wrote: > > >Given: a 'dipole' is rated at at 2.13 dbi. Does this apply for > >transmit only, or does it include receive also? > > Yes, it includes receive. > > >The ARRL defines a dipole as a half-wavelength fed at the center. > >Define dipole. Define feed. > > There was a discussion here awhile back on this. I personally > consider any antenna with two physical poles to be a dipole, but > not everyone agrees with that. Some believe that to qualify as > a dipole, the antenna must also have two electrical poles, that > is, it must be resonant. > > When used as a noun, "feed" is the power made available to > the load. It is sometimes also used to describe the method > of delivering that power. > > >Here are my conditions for a 'half-wavelength dipole': > > > >A. A dipole of 'average' wire size, and 'average' physical length > >which brings it into resonance. Feed is one side hot(coax center), > >and the other side is not hot(coax shield or ground). > > This won't create a true dipole unless a balun is used or unless > the transmission line is a length that prevents RF current from > flowing back down the line on the outside of the shield. > > >B. A dipole of 'average' wire size, and 'average' physical length > >which brings it into resonance. Feed is balanced ladder > line(300/450 etc.) Both halves of the dipole are driven. > > This will create a dipole, although with certain deviations from > a theoretical model due to practical considerations. > > >C. A dipole of very thin(<50 gauge) wire, fed as in A. Length > >approaches free space length. > > Not a true dipole. > > >D. A dipole of very thin(<50 gauge) wire, fed as in B. Length > >approaches free space length. > > The RF resistance of extremely small wire will reduce the gain. > > >E. A dipole of very thick (i.e. 2 inch diameter) wire, fed as in A. > >The length now is very short physically. > > Not a true dipole. > > >F. A dipole of very thick (i.e. 2 inch diameter) wire, fed as in B. > >The length now is very short physically. > > Generally speaking (and ignoring factors such as losses in the > matching network), gain will be close to that of the dipole in B. > > >G. A dipole as in A, but balun fed(toroid sleeve) so that both sides > >are radiating and receiving. Applies to C and E also. > > This simply creates a true dipole. > > >Which of these 'dipole' antennas will give the 2.13 dbi figure? > > Maybe none. Assuming that only the power actually delivered to > the feedpoint of the antenna is considered, the gain will vary > with height above ground and soil conditions. If the power at > the output of the transmitter is the reference, system gain will > vary with losses in the matching network (if any), transmission > line and balancing device. > > >There will be a measurable difference between a thin and thick > >wire. Is there a difference? Does the cross-sectional area of the > >thin wire equal the cross-sectional area of the thick wire? > > Cross-sectional area is not a factor. Due to skin effect, > surface area is the dimension that will affect RF resistance. > > >How many db's gain or loss does G have over A? > > That's impossible to know. Current flowing down the outer shield > in A will rob the antenna proper of current and will skew the > radiation pattern. > > >With these things in mind, how much of dbd gain does YOUR antenna > >have? > > Not enough. ;) > > 73, > Jack WB3U Jack, I think you're missing something here. The dipole he's referring to is the THEORETICAL dipole. It is a mathematic model with wires that have zero resistance, negligible size, it assumes a center, balanced feed, and each half is 1/4 wave. Yes, this *theoretical* dipole will have the 2.13 dB gain compared to an isotropic radiator. I remember computing the antenna patterns of such a dipole in my EE studies at the Johns Hopkins University's Electricity and Magnetism class. It's been over six or seven years since I did it and the math wasn't exactly pleasant. I don't think I could (or should) repeat it here. Jake Brodsky, AB3A, "Beware of the massive impossible!" From amsoft@epix.net Tue May 07 19:37:21 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: 7 May 1996 04:20:07 GMT Message-ID: <4mmj1n$6kg@news.asu.edu> Roy said - There's one more thing about the 2.15 dBi dipole. It's in free space. This makes it as much a fictitious antenna as an isotropic radiator. Oh no. Graham doesn't believe in *displacement current* and now Roy says that the isotropic radiator is FICTITIOUS. Next someone will say that there is NO SANTA CLAUS and NO EASTER BUNNY. Charlie, W7XC -- From amsoft@epix.net Tue May 07 19:37:22 1996 From: Alan Huckerby Newsgroups: rec.radio.amateur.antenna Subject: Re: Distance between two 2M antennas operating simultaneously? Date: Sun, 5 May 1996 15:14:43 +0100 Distribution: world Message-ID: References: <4me36u$dd6@news.connectnet.com> In article <4me36u$dd6@news.connectnet.com>, David Negaard writes >I'm thinking about operating two 2M radios on two (probably not widely >separated) frequencies. One will be a Mitrek set up to operate 9600 >bps packet, and the other may be set up to operate 1200 bps packet or >FM voice. > >My question is, how far apart do the antennae need to be in order to >avoid problems? > ----CUT >-- A good rule of thumb is 2 Lambda (around 4mts/13feet in your case), thats vertical on the mast/support. Regards -- Alan Huckerby (G8HJL - Lapsed!) From amsoft@epix.net Tue May 07 19:37:24 1996 From: macino@mail.fwi.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Electric half-wavelenght xmition lines... Date: 4 May 1996 01:01:18 GMT Message-ID: <4mea8u$opm@news.fwi.com> References: <24523@SP-gw.ampr.org> <4me6ie$m8b@news.fwi.com> Reply-To: macino@mail.fwi.com In <4me6ie$m8b@news.fwi.com>, macino@mail.fwi.com writes: >In <24523@SP-gw.ampr.org>, py3crx@sp-gw.py2bjo.ampr.ORG writes: >>Hi all: >>Some days ago I'd posted a msg. asking if it's valid take antenna >>measurements (HF range) using a RX Noise Bridge conectet to a antenna >>trhu a electric half-wavelenght transmition line. >>This particular line lenght (and it's multiples) will be "transparent" to >>complex impedances? >>What will occur with the SWR at the line? I'll have an "isolated path" >>from XMTR and antenna? >>If I use a transmatch at the transmitter site, an electric half-walelenght >>transmition line, and any antenna, this transmatch will "see" the load >>as-is? And the SWR at the transmition line? >>Any help? >>Thanks. Marcus Ramos. PY3CRX@SP-GW.AMPR.ORG - Sao Paulo - Brasil > > > Marcus, > I think you are making a correct assumption that an electrical half-waveleng th >should be transparent. Using a noise bridge is a fairly accurate method of en suring >the half wave length. > Jim WD9AHF > >There is a copy of COAX2.EXE on the latest QRZ CD-ROM that will let you >graphically see the difference between physical and electrical lengths by >frequency. The program requires OS/2 Warp to run. From amsoft@epix.net Tue May 07 19:37:25 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Electric half-wavelenght xmition lines... Date: 3 May 1996 14:34:17 GMT Message-ID: <4md5h9$sut@itnews.sc.intel.com> References: <24523@SP-gw.ampr.org> py3crx@sp-gw.py2bjo.ampr.ORG wrote: >If I use a transmatch at the transmitter site, an electric half-walelenght >transmition line, and any antenna, this transmatch will "see" the load >as-is? And the SWR at the transmition line? Hi Marcus, neglecting losses, transmission line impedances repeat every half wavelength. Losses include any nearby objects that might upset the current balance in ladder-line. So measurements made a half-wavelength from the antenna reflect the antenna impedance minus losses in the transmission line. Whether one considers transmission line losses neglible or not depends on the required accuracy of the measurements. With an 'S' unit being 3-6 dB, I personally consider 1 dB of loss to be neglible although one can readily measure that amount of loss. You can measure or estimate the matched-line loss in a transmission line. You can then calculate the expected additional loss from standing waves. You can then factor this loss into your measurements if you consider them not neglible. 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Tue May 07 19:37:26 1996 From: macino@mail.fwi.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Electric half-wavelenght xmition lines... Date: 3 May 1996 23:52:18 GMT Message-ID: <4me67j$m8b@news.fwi.com> References: <24523@SP-gw.ampr.org> Reply-To: macino@mail.fwi.com In <24523@SP-gw.ampr.org>, py3crx@sp-gw.py2bjo.ampr.ORG writes: >Hi all: >Some days ago I'd posted a msg. asking if it's valid take antenna >measurements (HF range) using a RX Noise Bridge conectet to a antenna >trhu a electric half-wavelenght transmition line. >This particular line lenght (and it's multiples) will be "transparent" to >complex impedances? >What will occur with the SWR at the line? I'll have an "isolated path" >from XMTR and antenna? >If I use a transmatch at the transmitter site, an electric half-walelenght >transmition line, and any antenna, this transmatch will "see" the load >as-is? And the SWR at the transmition line? >Any help? >Thanks. Marcus Ramos. PY3CRX@SP-GW.AMPR.ORG - Sao Paulo - Brasil From amsoft@epix.net Tue May 07 19:37:28 1996 From: py3crx@sp-gw.py2bjo.ampr.ORG Newsgroups: rec.radio.amateur.antenna Subject: Electric half-wavelenght xmition....re:... Date: 6 May 96 00:00:29 GMT Message-ID: <27988@SP-gw.ampr.org> Rich Griffiths wrote: >You now have many answers to these questions that all basically confirm >one another. >But remember that a line can be an electrical half-wavelength (or a >multiple of a half-wavelength) at only one frequency. You won't be >able to count on its "transparency" across a very wide band, like 80 m. Ok Rich, it's true! This aproach came to discussion between me and another ham here some time ago. We're considering any method to take measurements remotely. The last option should be a kind of RX noise bridge that we can mount (and control!) remotely, to be installed at the prototypes feed point. In my real situation, as I wrote at some answer concerning such question, I'm placed at a vy. urbanized area (according to the hams here in Sao Paulo, I got the worse place in the town to radio works! - I got it!). But I still doing some antenna tests and checking the softwares predictions against the real world. At least concerning impedances. The other thing I have in mind for such 1/2WL xmition line is that having a "random" wire outside I'll transfer the "Z" to inside the shack. I knew abt. bandwidht limits. But again, in my real situation, at least at some portion of each band I'll have any kind of "transparency" and "shielding". Take a 75 ohm CATV coaxial cable(I work for a CATV MSO here). Somewhere I read(1980 Ham Radio Magazine, some broadband coaxial baluns.. . article) that the high the coax Z, the broader the xformer. And the ideia is to use a 7.08MHz 1/2WL line to 40 and add(or subtract) small cable pieces to got some 1/2WL multiple at different frequencies. At the ends of this line, some kind of "RF coils", like 1:1 balun, to isolate the xmition line. At least the intention is to shield the path between the transmatch and antenna - the neighbours will love it!. Thanks for the comments and best regards. Marcus Ramos - PY3CRX@SP-GW.AMPR.ORG - Sao Paulo - Brasil. From amsoft@epix.net Tue May 07 19:37:29 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Ethernet Cable Date: 6 May 1996 20:07:23 GMT Message-ID: <4mlm5r$qip@itnews.sc.intel.com> References: <0000121B00000B93@prostar.com> <4mg3ki$94b@news.pathcom.com> gorslin@pathcom.com (Gorsline Family) wrote: >Given its an indoor cable (fire rated FT4/FT6...), will the orange jacket tak e >outside abuse (weather, UV, etc.)? It is *not* UV protected and lasts less than a year in the sun around Phoenix. If one has unused ethernet cable and UV protects it, it's a pretty good HF/VHF cable especially if it's free. I've used it inside old garden hoses. 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Tue May 07 19:37:29 1996 From: William Osborne Newsgroups: rec.radio.amateur.antenna Subject: Re: Force 12 Log Periodic Antennas? Date: 6 May 1996 13:42:58 GMT Message-ID: <4mkvl2$anf@news.utdallas.edu> References: <4mg63j$k2b@doc.zippo.com> I called and ask about these and I was given a sales pitch as to why it is so difficult to get LP's to work ask described in the books! I think the mention of LP's in their catolog is to get you not to buy one! -- William P. Osborne, AA5ZQ wosborne@utdallas.edu 214-883-2974 From amsoft@epix.net Tue May 07 19:37:30 1996 From: armond@delphi.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Help: 6m Dipole Ant Date: Fri, 3 May 96 01:56:06 -0500 Message-ID: References: <4lp20o$1nn2@mule2.mindspring.com> <4m5gpa$rqr@news.dx.net> Doug D writes: >A 5/8 Vertical would be 11 feet, 0 inches long. That is not correct! From amsoft@epix.net Tue May 07 19:37:31 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna Subject: Re: Help: 6m Dipole Ant Date: 6 May 1996 17:51:21 GMT Message-ID: <4mle6p$3ei@news.service.uci.edu> References: <4lp20o$1nn2@mule2.mindspring.com> <4m5gpa$rqr@news.dx.net> In article , armond@delphi.com says... >Doug D writes: >>A 5/8 Vertical would be 11 feet, 0 inches long. >That is not correct! Then what is it? (Approx) Brian From amsoft@epix.net Tue May 07 19:37:32 1996 From: bclongwell@delphi.com (Brian Longwell) Newsgroups: rec.radio.amateur.antenna Subject: HF Mobile Antenna type/placement Date: 6 May 1996 02:54:05 GMT Message-ID: <9605052256591.The_Win-D.bclongwell@delphi.com> I've been trying out a few different HF antenna options and wanted to get some opinions. My car is a Chevy Blazer. So far, I have focused on antennas mounted on the roof rather than the side or the hitch. My somewhat questionable field strenth measurements have been made using 4 different antennas all on 75 meters: 1) Hamstick, 2) Hustler center loaded Super Resonator ~9' tall, 3) Hustler Super Resonator with shorter mast ~6' tall, 4) Home made base loaded with 4" diameter coil/#14 wire and 9' total hight. The Hamstick and the shortened Hustler performed about the same. The full-size hustler gave about 2.5 gain over the Hamstick, and the base loaded antenna (!) was about .5 db better than the full-size Hustler. The reason must be due to the higher Q of the homemade coil. The Hamstick is easiest to deal with on the roof, but the full-size Hustler is totally unmanagable. The base loaded version was workable, except I did find myself temporarily loading up to a few overpasses on the highway. If I chop off another 6", I should be OK. I would like to try the highly recommended screwdrivers, but these are definitly not roof-top type antennas. My question is, what degradation in performance might be expected in mounting a full-size Hustler or screwdriver on the back side (with the base 2~2.5' below the roof line) of the Blazer. The screwdriver is appealing for its remote tune ability. The homemade base loaded version is appealing because I have concocted a remote raise/lower contraption to get me through tolls, cities, parking garages, etc. The base of the antenna is near the back on a pivit. I used a power window motor to crank it up/down. When down, it lays on the roof, looking like I'm off for some fishing rather than the giant bumper car look. Thanks for the feedback. Brian WB2DSH From amsoft@epix.net Tue May 07 19:37:33 1996 Newsgroups: rec.radio.amateur.antenna From: ghiscox@netcom.com (George L. Hiscox) Subject: Re: HF Mobile Antenna type/placement Message-ID: References: <9605052256591.The_Win-D.bclongwell@delphi.com> Date: Mon, 6 May 1996 16:14:56 GMT bclongwell@delphi.com (Brian Longwell) wrote: >I've been trying out a few different HF antenna options and wanted to get som e >opinions. My car is a Chevy Blazer. So far, I have focused on antennas >mounted on the roof rather than the side or the hitch. My somewhat >questionable field strenth measurements have been made using 4 different >antennas all on 75 meters: 1) Hamstick, 2) Hustler center loaded Super >Resonator ~9' tall, 3) Hustler Super Resonator with shorter mast ~6' tall, 4) >Home made base loaded with 4" diameter coil/#14 wire and 9' total hight. <------------------------WHACK-------------------------> Brian, There is an EZNEC model of a Chevy Blazer (blazer.zip) available for anonymous ftp from emclab.ee.umr.edu/pub/aces/NEC/EZNEC_FILES . Using the vehicle model, you can then model your various antennas in different mounting locations and get a good idea of what results to expect. The EZNEC software is available from Roy Lewallen, W7EL, who also posts to thi s newsgroup. I have found it very useful and a whole lot of fun to use. 73/George ----- George L. Hiscox | Very funny Scotty, now | ghiscox@netcom.com | beam down my clothes!!! | WA6RIK@WB6YMH.#soca.ca.usa.na | ^^^^^^^^^^^^^^^^^^^^^^^ | [Finger ghiscox@netcom.com for PGP Public Key] From amsoft@epix.net Tue May 07 19:37:34 1996 From: cqcqcq@ipoline.com (Dan Tang) Newsgroups: rec.radio.amateur.antenna Subject: HF Vertical Date: Fri, 3 May 1996 22:37:00 -0500 Message-ID: Can some one please tell me if an hf vertical antenna install on the roof (with radials) works as good as it install on the ground (with radials)? From amsoft@epix.net Tue May 07 19:37:35 1996 Newsgroups: rec.radio.amateur.antenna From: n4lq@iglou.com (Steve Ellington) Subject: Re: HF Vertical Message-ID: References: <318B4DA9.52C1@interealm.com> <318E30B4.49E4@aa6g.org> Date: Mon, 6 May 1996 22:59:13 GMT Works good on roof if radials base of vert is up at least 1/4 wave from roof peak. Otherwise, expect interaction with house wiring and RFI problems. Also expect birds to set on wire and poop on roof. This leaves large, white X on roof which marks your house for even larger birds. -- Steve Ellington N4LQ@IGLOU.COM Louisville, Ky From amsoft@epix.net Tue May 07 19:37:36 1996 From: Chuck Vaughn Newsgroups: rec.radio.amateur.antenna Subject: Re: HF Vertical Date: Mon, 06 May 1996 09:02:44 -0800 Message-ID: <318E30B4.49E4@aa6g.org> References: <318B4DA9.52C1@interealm.com> George J. Molnar wrote: > > Dan Tang wrote: > > > > Can some one please tell me if an hf vertical antenna install on the roof > > (with radials) works as good as it install on the ground (with radials)? > > It'll probably work a bit better, presuming you install a good-quality > set of radials on the roof. And not only that, but you can get the impedance closer to 50 ohms by sloping the radials down. Chuck - AA6G From amsoft@epix.net Tue May 07 19:37:38 1996 From: pgram@mbox.vol.it Newsgroups: rec.radio.amateur.antenna Subject: Re: Horizontal HF loops Date: Sat, 04 May 1996 14:44:59 GMT Message-ID: <4mfqhs$ijd@everest.vol.it> References: <317CF945.31D2@ldp.com> <4lteku$6aq@consolidated.ccinet.net> greenthumb@iss.com (GreenThumb) wrote: >Rolfe Tessem wrote: >>Monty Wilson wrote: >>> >>> A friend of mine is experimenting with horizontal HF loops. He >>> built one to resonate on 80, thinking he could use it on any multiple >>> of the principal frequency. >>Rolfe >>W3VH >About 8 years ago, I installed a 75M horizontal loop. I used it not >only for amateur use, but also for Navy/MC MARS. The first evening I >went on 4515 MARS, they asked me to turn off the amplifier. The loop >does indeed tend to exhibit the "straight up, straight down" effect on >lower frequencies, to some extent. But my "killer" footprint on 4515 >was basically the middle third of the US (I'm in Illinois). What is >NOT generally known (but was exposed in a very good article complete >with charts in QST, I believe it was - and if I can find the article >again I'll let you know) is that on higher frequencies, the horizontal >loop is an EXTREMELY good DX antenna, especially when mounted >relatively low. My loop was at 25 feet, and if you look at a copy of >my log during the time I used this antenna, running usually abt 50 >watts, occasionally but rarely up to 300 watts, you can see the >concrete results. Apparently when mounted in this way, the loop is >basically multiple wavelengths, and the charts show INCREDIBLE >low-angle radiation. Here is my experience: A while ago, I found on page 5-16 of The ARRL Antenna Book a description of the Loop Skywire. Since I have a lot of space, i upscaled it to a full size 160 meters loop. From 7 mhz up, the results are astounding. I use a FD4 windom for comparison, and my loop is from 12 to 24 feet high suspended between trees in a forest. on 14 mhz, switching from the FD4 to the loop makes the noise disappear and the signal to pop up as if the preamp was on. the reports are jumping from 549 to 599 constantly. the cost was near to nothing, and the line is just a 25 feet of rg213 directly connected to the corner of thel loop. the line is so short than any matching will be useless. try it! ik4yng paolo From amsoft@epix.net Tue May 07 19:37:40 1996 From: pgram@mbox.vol.it Newsgroups: rec.radio.amateur.antenna Subject: Re: Horizontal HF loops Date: Sat, 04 May 1996 14:44:50 GMT Message-ID: <4mfqhj$ijd@everest.vol.it> References: <317CF945.31D2@ldp.com> <4lteku$6aq@consolidated.ccinet.net> greenthumb@iss.com (GreenThumb) wrote: >Rolfe Tessem wrote: >>Monty Wilson wrote: >>> >>> A friend of mine is experimenting with horizontal HF loops. He >>> built one to resonate on 80, thinking he could use it on any multiple >>> of the principal frequency. >>Rolfe >>W3VH >About 8 years ago, I installed a 75M horizontal loop. I used it not >only for amateur use, but also for Navy/MC MARS. The first evening I >went on 4515 MARS, they asked me to turn off the amplifier. The loop >does indeed tend to exhibit the "straight up, straight down" effect on >lower frequencies, to some extent. But my "killer" footprint on 4515 >was basically the middle third of the US (I'm in Illinois). What is >NOT generally known (but was exposed in a very good article complete >with charts in QST, I believe it was - and if I can find the article >again I'll let you know) is that on higher frequencies, the horizontal >loop is an EXTREMELY good DX antenna, especially when mounted >relatively low. Here is my experience: On the 17th edition of the Antenna Book, at page 5-16, there is a description of the Loop Skywire. I simply upscaled it to a double size, 160 meters long loop, and I use it on every band from 160 meters up. The rig is a ICOM 781, 150W, with internal tuner; the loop is installed at a quite low height, suspended between the trees in a forest (average, 12 feet to 20 feet) and was made resonating at 7.05 mhz, where the ROS is still about 4:1 due to an unfavorable resistance (maybe 200 Ohm). Since my rig is about 15 feet directly below one corner of the loop, i forgot the ROS and simply connected some RG213 directly to the loop corner, shield to one side and wire to the other. At the beginning, i tried to use a balun, but it works better without it, and the line is so short than the ROS does nothing bad (virtually no attenuation). From 7 mhz up, the results are astounding. I have a Windom F4D as a comparison, and switching between the windom and the loop at 14 MHZ is umbeliable: the noise disappears, and the signal pops out. On DX stations, I get 599 against a 559 on the FD4. Assuming the space is available (the footprint is 150 X 150 feet) the cost is so cheap that everybody should try it!!! Quite soon I will try to clip it to the original 80 meters lenght. I just want to see the difference; all of the wire is now suspended through pulleys, so it's a two hours job anyway! By The Way!!! Does anybody knows where I can buy a surplus Antenna Bridge, like the General Radio? I need it, and I will pay top cash!! 73, from IK4YNG From amsoft@epix.net Tue May 07 19:37:41 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: Horizontal HF loops Date: Sun, 05 May 96 17:00:44 GMT Message-ID: <4miqss$fla@crash.microserve.net> References: <317CF945.31D2@ldp.com> <4lteku$6aq@consolidated.ccinet.net> <4mfqhj$ijd@everest.vol.it> pgram@mbox.vol.it wrote: >On the 17th edition of the Antenna Book, at page 5-16, there is a >description of the Loop Skywire. I missed the earlier posts in this discussion, but I'm interested in that antenna also. Do you know why the Antenna Book says not to use a balun? What prevents coax feedline radiation? >I simply upscaled it to a double size, 160 meters long loop, and I >use it on every band from 160 meters up. > >The rig is a ICOM 781, 150W, with internal tuner; the loop is >installed at a quite low height, suspended between the trees in a >forest (average, 12 feet to 20 feet) and was made resonating at 7.05 >mhz, where the ROS is still about 4:1 due to an unfavorable >resistance (maybe 200 Ohm). If I build one of these, it will also be for 160M and the installation will be almost identical to yours. The wire will have to run through the woods and be suspended on trees. However, my feedline is much longer, about 100', so I'm concerned about loss. I use ladder line, but even so, extremely high SWR can create significant loss on a line this long. >Since my rig is about 15 feet directly below one corner of the loop, >i forgot the ROS and simply connected some RG213 directly to the loop >corner, shield to one side and wire to the other. Is the feedpoint impedance of these antennas more moderate across the bands than a random dipole? If the loop is cut for 160M like yours, how significant is the SWR on the other bands, particularly those that are not an integral multiple of the fundamental? What have you measured for SWR on the various bands? >At the beginning, i tried to use a balun, but it works better without >it, and the line is so short than the ROS does nothing bad (virtually >no attenuation). What characteristic improved when the balun was removed? 73, Jack WB3U From amsoft@epix.net Tue May 07 19:37:42 1996 From: billp8@atl.mindspring.com (Bill Poston) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew Subject: HOW DO U CONNECT COAX TO QUAD???????? Date: Sun, 05 May 1996 02:47:42 GMT Message-ID: <318c1477.108916@news.atl.mindspring.com> I am attempting to homebrew a quad antenna. I have read Cubical Quad Antennas by W6SAI and the ARRL Antenna Book. Neither answers my question. How do I connect one coax feedline to the multiple loops on the driven element? Please explain in detail so that a dummy can understand. Thanks in advance for your help. Email would be appreciated. Bill N4BVS ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Bill Marietta, Ga. ================== THIS TOO, SHALL PASS ================== From amsoft@epix.net Tue May 07 19:37:43 1996 Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew From: Monty Wilson Subject: Re: HOW DO U CONNECT COAX TO QUAD???????? Message-ID: Date: Mon, 6 May 1996 21:07:06 GMT References: <318c1477.108916@news.atl.mindspring.com> billp8@atl.mindspring.com (Bill Poston) wrote: >I am attempting to homebrew a quad antenna. I have read Cubical Quad >Antennas by W6SAI and the ARRL Antenna Book. Neither answers my question. > >How do I connect one coax feedline to the multiple loops on the driven >element? > >Please explain in detail so that a dummy can understand. I believe you just tie them together: /----------------\ | | | /---------\ | | | | | | | | | | | /---\ | | | | | | | | | | | | | | | | | | | | | | \ / | | | | | | | | | | | | | | | \---+ +---/ | | | | | \-------+ +------/ | | \-O H H -- .........Monty. mwilson@flex.net From amsoft@epix.net Tue May 07 19:37:45 1996 From: Edward Lawrence Newsgroups: alt.binaries.pictures.erotica.amateur.female,alt.binaries.erotic.senior-citizens,alt.binaries.pictures.erotic.senior-citizens,alt.binaries.pictures.erotica.breasts,alt.binaries.pictures.erotics.breasts,alt.binaries.pictures.voyeurism,alt.freemasonry,alt.masonic.members,alt.banjo.clawhammer,alt.binaries.sounds.midi,rec.radio.amateur.antenna,rec.radio.amateur.digital.misc,rec.radio.amateur.equipment,rec.radio.amateur.misc,alt.appalachian,alt.binaries.clip-art,k12.ed.music,alt.sex.fat,rec.sex,alt.consumers.sweepstakes,sci.numerology Subject: Re: Looking for info on numerology Date: 6 May 1996 12:56:57 GMT Message-ID: <4mksup$42c@fcnews.fc.hp.com> References: <4lp7o9$nhr@news.mountain.net> <318A23BD.2462@adnc.com> Why are you posting this material to rec.amateur.antennas? This is about as far off topic as you can get . Please don't do it again. From amsoft@epix.net Tue May 07 19:37:46 1996 From: "George J. Molnar" Newsgroups: rec.radio.amateur.antenna Subject: Re: Need plans for HF antenna Date: Sun, 05 May 1996 07:08:16 -0600 Message-ID: <318CA840.6CAE@interealm.com> References: <318BE633.31FA@cancom.net> Reply-To: gmolnar@interealm.com To: Francois Meehan Francois Meehan wrote: > > Is there a WEB site where I can find plans, design for HF antenna on the > Web or anywhere on the net? > Exactly what KIND of HF antenna?? I'm not sure of any general-information sources, but you might want to to a search on "antennas" and "HF" or "ham", etc. I've got a page full of search engine forms at: http://www.interealm.com/p/gmolnar/webtools.html 73 -- George J. Molnar Highlands Ranch, Colorado Amateur Radio: KF2T@N0QCU.#NECO.CO.USA.NOAM http://www.interealm.com/p/gmolnar/index.html From amsoft@epix.net Tue May 07 19:37:47 1996 From: forrest.gehrke@cencore.com (FORREST GEHRKE) Newsgroups: rec.radio.amateur.antenna Subject: Re: OFC and OOTC Message-ID: <8C00328.02CF0010AE.uuout@cencore.com> Date: Sun, 05 May 96 13:28:00 -0300 Distribution: world Reply-To: forrest.gehrke@cencore.com (FORREST GEHRKE) References: <4m9c73$m6h@nadine.teleport.com> RL> >I have been noticing Roy Lewallen's signature of OFC. . . >of Old RL> Farts Club . . . RL> Oh, no. Is THAT what it stands for??? Roy, It could also stand for Old Fogies Club. But people born in 1946 still qualify! ;-) I must admit, I like my rendition better. But it's your club; tell us your name for it. Hmmm.... --k2bt * RM 1.3 02583 * Old age isn't so bad when you consider the alternative. From amsoft@epix.net Tue May 07 19:37:48 1996 From: Matteo Montanari Newsgroups: rec.radio.amateur.antenna Subject: only test Date: Mon, 06 May 1996 19:03:28 +0200 Message-ID: <318E30E0.41C3@estense.global.it> only test From amsoft@epix.net Tue May 07 19:37:49 1996 From: S.Y.Stroobandt@e-eng.hull.ac.uk Newsgroups: rec.radio.amateur.antenna Subject: Q: Matching to an extreme high impedance Date: 7 May 1996 05:58:51 -0700 Message-ID: <4mnheb$qu9@doc.zippo.com> Hello, I need to match a source of 50ohms to a load of approx. 100kohms or even higher in parallel with a capacitance of 10nF at frequencies up to 30MHz and power levels up to 1kW. The matching network needs to have a loaded Q that can be freely chosen. Any suggestions? Thanks in advance & 73 de G/ON4BAA, Serge From amsoft@epix.net Tue May 07 19:37:49 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Q: Matching to an extreme high impedance Date: Tue, 07 May 96 20:28:48 GMT Message-ID: <4mobnr$7n8@nadine.teleport.com> References: <4mnheb$qu9@doc.zippo.com> In article <4mnheb$qu9@doc.zippo.com>, S.Y.Stroobandt@e-eng.hull.ac.uk wrote: >Hello, > >I need to match a source of 50ohms to a load of approx. 100kohms >or even higher in parallel with a capacitance of 10nF at frequencies >up to 30MHz and power levels up to 1kW. >The matching network needs to have a loaded Q that can be freely chosen. >Any suggestions? > >Thanks in advance & 73 de G/ON4BAA, Serge You might try connecting the load to a grounded parallel-resonant circuit and the source to a tap on the inductor (or use a capacitive divider for the capacitor, with the source to the capacitor "tap"). Vary the loaded Q by changing the L/C ratio. Roy Lewallen, W7EL From amsoft@epix.net Tue May 07 19:37:50 1996 From: bowman@montana.com (robert bowman) Newsgroups: rec.radio.amateur.antenna Subject: Re: questions on loop antenna Date: 4 May 1996 14:19:44 GMT Message-ID: <4mfp20$bv4@maw.montana.com> References: <4mcfb2$ppc@venus.compulink.gr> In article <4mcfb2$ppc@venus.compulink.gr>, zliangas@compulink.gr (Zacharias L iangas) says: >To my surprise the antenna did not show resonace with capacitor but >inly without capacitor and at the first 2-3 wounds ! >Its results were s not so satisfactory for me as the LOwe HF150 in >its ATT position, together with 8 m of RG 59 and clips to the >antenna's zero and 2 nd wound showed lower signals than of mine AIWA >J150 if i am reading this correctly, you are connecting the HF150 directly across the loop? if so, this may be your problem. try link coupling the receiver with a one or two turn loop. the other alternative is using a FET circuit from the loop to drive the receiver. this doesn't have to amplify, it just presents a very high input impedance to the loop, to keep the Q high and give you sharp tuning. From amsoft@epix.net Tue May 07 19:37:51 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: Radiation resistance Date: 3 May 1996 21:29:15 GMT Message-ID: <4mdtrb$qnl@news.asu.edu> Richard, Note restriction to 90 degree each-side-limit and resistive component of input impedance only added to my previous posting. Here is a fairly simple approximation of Rr seen at the center feedpoint of a horizontal dipole (possibly either not loaded, inductively loaded at any point or end capacity loaded; in freespace and assuming sinusoidal current distribution. This Rr will vary with height above earth on a curve of Rr vs height oscillating about the free space value as a damped sinusoid approaching the free space value at great heights and decreasing with height below about .2 wavelength height to some small value at zero height. Note: Rr does NOT include earth loss, copper loss of the wire or loss resistance of any loading coils. Earth loss is generally negligible at heights above about .2 wavelengths. Rr = 70 (sin L1 + cosL1(1 - cosL2)/sinL2)) ^2 Where: L1 = angular length of section below loading coil L2 = angular length of section above loading coil. angular length = .366 h f Where h = length in feet of each side of the dipole and f = frequency in MHz. Maximum overall angular length (L1 + L2) is 90 degrees per side. This equation applies to any loading coil position including loading at the feedpoint (L1 = 0) and purely capacitive end loading where L2 = 0. Coil loss resistance reflected to the feedpoint will be approximately Rc cos^2 L1 Where Rc is the loss resistance of the coil. But because the current distribution is not quite sinusoidal, the actual value will be somewhat greater. This loss resistance from copper loss of the antenna wire (usually negligible except for otherwise high efficiency very short antennas), coil loss and earth loss are added to Rr to form the input resistance component of impedance of the antenna center feedpoint. If the antenna is not resonant there will be a reactive component in addition resistive component. -- From amsoft@epix.net Tue May 07 19:37:53 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: Small loop over a lossy earth Date: 3 May 1996 13:05:49 -0400 Message-ID: <4mdedd$bcp@newsbf02.news.aol.com> References: <4man2s$2e9@news.cc.geneseo.edu> Hi Michele, In article <4man2s$2e9@news.cc.geneseo.edu>, Michele Piscopo writes: >Hi guys, >I' m searching for information about the efficiency of small loop >antennas when located near a lossy earth. > >I believe that, being the near field essentially magnetic, and being the >losses due to almost the only electric fields, the small loop antennas >can work also at little heights without inducing appreciable losses in >the ground... Do not count on that. The small loop is also lossy because magnetic coupled losses are also high in poor soil, plus the "electromagnetic wave" effect is the same even with a small loop. >An exact study of the electromagnetic problem could be done using the >Sommerfeld integrals to evaluate the field in the ground and integrating >the quantity S * abs(E) in the lower half-space (where S is the ground >conductivity and abs(E) is the modulus of the electric field). >Anyway I would like to know if someone tried to make a comparison >between a conventional antenna and a small loop or, better, if someone >tried to evaluate the efficiency of the small loop over a lossy earth as >function of the height h using a numerical antenna simulator (just as >NEC...). I found in field strength measurements a small vertical loop near soil here (around 4 mS/m) was about 4 dB down at high wave angles compared to the same antenna at the same height (one loop diameter) over a good groundplane, and efficiency dropped rapidly as the antenna was placed near earth. There seem to be very few ways to get something for nothing. 73 Tom From amsoft@epix.net Tue May 07 19:37:54 1996 From: Michele Piscopo Newsgroups: rec.radio.amateur.antenna Subject: Small loop over lossy earth. Date: 6 May 1996 11:07:26 GMT Message-ID: <4mkmhe$689@server-b.cs.interbusiness.it> Hi guys, I' m searching for informations about the efficiency of small loop antennas when located near a lossy earth. I believe that, being the near field essentially magnetic, and being the losses due to almost the only electric fields, the small loop antennas can work also at little heights without inducing appreciable losses in the ground... An exact study of the electromagnetic problem could be done using the Sommerfeld integrals to evaluate the field in the ground and integrating the quantity S * abs(E) in the lower half-space (where S is the ground conductivity and abs(E) is the modulus of the electric field). Anyway I would like to know if someone tried to make a comparison between a conventional antenna and a small loop or, better, if someone tried to evaluate the efficiency of the small loop over a lossy earth as function of the height h using a numerical antenna simulator (just as NEC...). From amsoft@epix.net Tue May 07 19:37:55 1996 From: thompson@atl.mindspring.com (David L. Thompson) Newsgroups: rec.radio.amateur.antenna Subject: Re: SOMMER antenna Date: Sun, 05 May 1996 00:56:38 GMT Message-ID: <4mh1bq$1bdi@mule1.mindspring.com> References: <4m60p7$7pd@everest.vol.it> Reply-To: thompson@atl.mindspring.com marcmag@mbox.vol.it (Marco Magnano) wrote: >73's to all the Ham in this newsgroup. >Is there any of you who has been testing or currently using the DJ2UT SOMMER >multi band no trapped beam? >I would like to know how it works. >In the advertisment it looks very good. >Best luck and good DX >IT9WPO Marco Magnano >marcmag@mbox.vol.it Marco...I know two hams that use the antenna (XP807) with very good results. Bob, N4VZ lives near Atlanta and Bill KM1E in Maine. Bill had a 2 or 3 part article in the DX magazine 2 years ago on selecting the antenna. Wish you had that article. Only bad thing I hear is it is more difficult to put together than many beams. I have a KT34XA and it cannot more difficult than that! Another antenna I think is very good is the Fritzel Dx 506 poly beam with 2el on 10, 17, 12 and 3 el on 20, 15. and 10. HE does use traps. Dave K4JRB From amsoft@epix.net Tue May 07 19:37:56 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: The Coax Mentality Date: 6 May 1996 19:31:01 -0700 Message-ID: <4mmcl5$ojm@nnrp1.news.primenet.com> References: <4m8ehm$m2a@itnews.sc.intel.com> <4m8usl$5mt@hpcvsnz.cv.hp.com> <4mavg8$g1i@itnews.sc.intel.com> <318A37C1.56FF@haven.ios.com> <4megu5$17o@nnrp1.news.primenet.com> <4mksr7$42c@fcnews.fc.hp.com> Edward Lawrence wrote: >So the feed line radiates and gives me an 'extra' vertical component. So what ? >How is that a 'mortal sin'? This is an honest question, not by any means a >flame. Thought I would make that 'perfectly clear". WA5SWD Hi Edward, that statement was my wierd sense of humor poking fun at some purists who consider certain aspects of ham radio as a religion. Guess I should have added a :-) 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Tue May 07 19:37:57 1996 From: marktaint@aol.com (MARKTAINT) Newsgroups: rec.radio.amateur.antenna Subject: What ladder line to use Date: 4 May 1996 09:55:19 -0400 Message-ID: <4mfnk7$4ks@newsbf02.news.aol.com> Reply-To: marktaint@aol.com (MARKTAINT) I'm considering stepping into (for me) uncharted waters and putting up an antenna using ladder line. My question is this: Does it make any difference which line I would use? 300 ohm and 450 ohm wire seem to be the most common although I read about 600 ohm feedline fairly regularly.. Are these lines used for specific purposes or can they be used in any application. I'm considering several possible antennas including center-fed dipoles as well as loop antennas. Thanks for any help you can give me with this question. 73, Mark Taintor, N0YRW From amsoft@epix.net Tue May 07 19:37:57 1996 From: asperges@innotts.co.uk (Jeremy Boot) Newsgroups: rec.radio.amateur.antenna Subject: WWW Pages Date: Sun, 05 May 1996 18:18:40 GMT Message-ID: <318cf001.5924610@news.innotts.co.uk> Reply-To: asperges@innotts.co.uk The local server programme which processes forms has thrown a wobbly this weekend, so if I've missed anyone's messages, please be patient. http://www.innotts.co.uk/~asperges/ The pages are still functioning fine however and have been recently updated. If you haven't visited yet, do please drop by. 73 de Jeremy G4NJH asperges@innotts.co.uk [Am Radio, SWL pages: http://www.innotts.co.uk/~asperges/ ] From amsoft@epix.net Sun May 12 18:01:35 1996 From: parf@aol.com (Parf) Newsgroups: rec.radio.amateur.antenna Subject: Re: "Patch" Antennas? Date: 11 May 1996 22:09:14 -0400 Message-ID: <4n3h8a$nav@newsbf02.news.aol.com> References: <28011@SP-gw.ampr.org> Reply-To: parf@aol.com (Parf) The antenna you describe sounds more like a bogner. It used disc parasites and a traditional horn exciter w/ a 1/4 W probe. The patch antenna was in QST- December issues have a yearly index. 73, Dale WA2YPY From amsoft@epix.net Sun May 12 18:01:36 1996 From: Shabanov Sergey Newsgroups: rec.radio.amateur.antenna Subject: 2.4 GHz antennas Date: 8 May 1996 12:38:34 GMT Message-ID: <4mq4ka$eeu@news1.demos.su> Help anybody! Where I can buy hi-gain (over 11dB) omni-directional trans-rec. antenna for WaveLAN 2.4 GHz? Sergey Shabanov Rosnet-International From amsoft@epix.net Sun May 12 18:01:37 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: Wed, 08 May 96 16:11:57 GMT Message-ID: <4mql67$j0b@crash.microserve.net> References: <4mq4ka$eeu@news1.demos.su> Post / CC by Mail Shabanov Sergey wrote: >Help anybody! > >Where I can buy hi-gain (over 11dB) omni-directional >trans-rec. antenna for WaveLAN 2.4 GHz? > > >Sergey Shabanov >Rosnet-International Andrew Corporation sells omnidirectional transmit antennas for MMDS (2.5 - 2.7 MHz) and MDS (2.1 MHz) that meet this specification. I'm sure they can provide one tuned for 2.4 GHz. Roughly speaking, these antennas sell for approximately $10,000. Andrew Corp. (U.S. callers): 800-255-1479 73, Jack WB3U From amsoft@epix.net Sun May 12 18:01:38 1996 From: moritz@ipers1.e-technik.uni-stuttgart.de () Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: 10 May 1996 17:50:06 GMT Message-ID: <4mvvke$13rc@info4.rus.uni-stuttgart.de> References: <4mq4ka$eeu@news1.demos.su> <831646102snz@microvst.demon.co.uk> >Maybe antenna theory has advanced beyond me. To show 11dB of gain over >any lossless omni-directional system and remain omni-directional seems >beyond the physics of passive systems. You will have to use amplifiers. Tony, Look how the term "omnidirectional" is defined: it commonly refers only to the azimuth. If you squash the pattern's elevational extention, you have an omnidirectional antenna with gain. Unlike many amateur (mystery) desighns, e.g. minibeams, ground planes without ground plane et.c, they are widely used in commercial applications and work. 73, Moritz DL5UH From amsoft@epix.net Sun May 12 18:01:39 1996 Newsgroups: rec.radio.amateur.antenna From: cbrown@lostnet.org (Christopher E. Brown) Subject: Antenna Design Info Message-ID: <577cc$11230.2ad@NEWS> Date: Tue, 07 May 1996 10:18:48 GMT Keywords: Antenna Hello all, looking for some antenna info. First off, jpoles, operation of. How much of a loss of transmit gain comes from operating a j-matched monopole with no ground plane? Second, colinear elements, vertical stacking of. What are the gain figures with the different methods? Heard everything from 1.8db (shorted stub delay line 1 - 2 inch spacing) to 2.9db (phasing coil 1/4 wave spacing). Also the delay sections, should they always be 90deg (1/2wave)? Or does one need a shorter delay on say stacked 5/8 wave elements? Any info would be of great help. Thanks BTW: Please CC: a copy to cbrown@matnet.com, the news server is a bit stupid right now. -- ---------------------------------------------------------------------------- Christopher E. Brown WL7CLA Lostnet Systems Administration ---------------------------------------------------------------------------- REAL PORTION of Microsoft Windows code: while (memory_available) { eat_major_portion_of_memory (no_real_reason); if (feel_like_it) make_user_THINK (this_is_an_OS); gates_bank_balance++; } ---------------------------------------------------------------------------- From amsoft@epix.net Sun May 12 18:01:40 1996 From: aor Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Location* Date: Sun, 05 May 1996 07:53:38 -0400 Message-ID: <318C96C2.3320@gteais.com> References: <9604260624231113@ctobbs.com> Jerry Boyd wrote: > > If anyone on here has access to TA or some other means of answering my > question (direct via jboyd@ctobbs.com) I'd really appreciate it. I'm > moving to a new QTH and am involved in HF Contests and DXing. New QTH > is at about 1900 feet elevation. Obstructions I am concerned about are: > Mountain peaks of 5100-5900 feet about 8 miles away from my QTH and > smaller peaks of 2800-3400 feet 2 1/2 - 3 miles away. Fortunately these > are all within about 90 degrees leaving 270 degrees unobstructed. Part > of the obstructed path is straight over the North Pole. Unfortunately, > the other is to JA. Problem?!?! > > Any info/thoughts appreciated > > Jerry Boyd > KG6LF Jerry, The mountain peaks that you describe are far enough away that they appear to be below 8-10 degrees from your radio horizion. For your signal to "hit" this, you need to be higher than 2 wavelength high on the frequency in use. For 20 meters, this means a tower/antenna combo higher than 120 feet. If your 1900' QTH raises you higher, then the mountains are really only 3-6 degrees above your horizion, then you would need to be 300' up!!! Big beams at 75-90' will work great. 10 Meters may be the only band with a take-off angle low enough to be a (slight) problem. Serious contesters use stacks of antennas with a BLU antenna switch (Both, Lower, Upper). On some band conditions, you may want to run the lower antenna for better skip, top-only, or both for a very-low take-off angle when needed. Read-up on the Yagi Antenna Handbook from ARRL. There are chapters dealing with antenna height and stacking for serious performance. I use this book for antenna design and stacking performance. 73, Al, NW2M President, MARC http://www.dsport.com/marc/ From amsoft@epix.net Sun May 12 18:01:41 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Tuner Baluns Date: Wed, 08 May 96 02:20:46 GMT Message-ID: <4mp4fl$3vh@crash.microserve.net> References: <4mm0v0$jka@news.linknet.net> Post / CC by Mail Jonathan Helis wrote: >Currently, I am using an antenna tuner that is a homebrew L-C network >with a single wire input. It was designed for end-fed single wire >antennas. I would like to make a 4:1 balun for this tuner so I can >feed it with twinlead. How to wind a balun is in the ARRL Handbook. >It looks easy, but I can't find anything suitable to wind it on. > >The Amidon catalog has tordoids in it like the diagram in the ARRL >Handbook. Has anyone ever done anything like this? What were your >results? I plan to run not more than 100 watts out of a Kenwood >TS-140S, into a small loop. Hi Jon, First, there are two spreadsheets on my FTP site that might help you design a balun if you have Excel 4.0 for Windows or something compatible. The files are labeled Toroid.xls and Flux2.xls. The FTP site is: ftp.microserve.com/popaccts/h/jackl/ The general rule of thumb when using Toroid.xls is that the the total XL of the winding should be four to five times the impedance of the circuit. Also, for toroids at the FT-240 size, the number of turns should probably be limited to ten or twelve to avoid excessive inter- winding capacitance. Finally, one of the best baluns consists of bifilar turns, wound on the toroid in a manner that creates a current balun. In this configuration, each winding is in series with one conductor of the line. That said, a balun needs to be used in a circuit that presents the input and output impedance the balun is designed for, within reasonable limits. Although the type of system you're planning is widely used, it doesn't meet that qualification. In order to assure balance and maximum transfer of power, you will need to use either A) a balanced tuner like a Match Box instead of the balun, or B) a technique employing variable line length with a tunable (simple) L/C network ahead of the balun. The latter will present the balun with a non-reactive load near its desired load impedance. Cecil Moore (KG7BK) has posted quite a few articles here regarding the latter technique and has written application notes. Those notes are being published by the company that makes the "Ladder Lizard", an inexpensive device for determining SWR, impedance and power on ladder line. The company's name is TechnoLogic Concepts and their e-mail address is: tlcdhconsult@delphi.com You might want to write and see if the notes are available yet. Maybe Cecil will jump in here with more details. ;) 73, Jack WB3U From amsoft@epix.net Sun May 12 18:01:43 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Tuner Baluns Date: 7 May 1996 22:07:02 -0700 Message-ID: <4mpa5m$kj3@nnrp1.news.primenet.com> References: <4mm0v0$jka@news.linknet.net> <4mp4fl$3vh@crash.microserve.net> jackl@pinetree.microserve.com (WB3U) wrote: >You might want to write and see if the notes are available yet. >Maybe Cecil will jump in here with more details. ;) Hi Jack, as far as I know, Don, KE6AJH, has information ready to email and is ready to ship. Just don't believe him when he says the Ladder-Lizard is better than sex. :-) I might explain the final solution (hi hi) here at my QTH. On a transmission line a little bit closer to the transmitter from the current maximum is what I call the PC point, where a single parallel capacitor will cause a Z0 match. If it happens at the transmitter, Z0 = 50 ohms and I call it the PC-50 point. So at the transmitter, I have a 20-200pf variable cap with the ability to switch in other fixed capacitors (thanks Tom). Capacitors are the only reactances that I use to achieve a 1:1 SWR on all frequencies on all HF bands. No lossy coils. How is it possible? If you can't bring the capacitor to a current maximum, then bring the current maximum to the capacitor. Outside my shack window, I have three relays that switch in 32 ft, 16 ft, and 8 ft sections of ladder-line. In the same box with my variable capacitor, I have three switches that will switch in 4 ft, 2 ft, and 1 ft sections of ladder-line. It's easy to see that I can vary my transmission line by 76 to 76+63=139 ft. I always use the shortest possible amount of transmission line to cut down on losses. That's my ultimate (so far) balanced matching system. 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Sun May 12 18:01:44 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Tuner Baluns Date: 11 May 1996 17:56:16 GMT Message-ID: <4n2kc0$jud@news.asu.edu> Cecil said - Of course, I realize this is the old stub-matching approach that my Elmer taught to me 45 years ago. But everything has come together in an easy-to-implement fashion. The only reason that I can think of why this is not the most popular matching system for balanced lines is people don't know about it or don't realize how easy it is to implement. I didn't mean to imply that this was anything new. Cecil, The same can be said about the Series Section Tranformer. some seem to think of only the quarter wave section which only by chance yields a required input impedance for a given termination and small choices of available line Zo. The series section transformer can use often available line Zo to get a wider range of impedances of input and termination. Charlie, W7XC -- From amsoft@epix.net Sun May 12 18:01:45 1996 From: lutzr@destin.nfds.net (Richard Lutz) Newsgroups: rec.radio.amateur.antenna Subject: AS 1181 UR Millitary antenna Date: 8 May 1996 22:11:26 GMT Message-ID: <4mr66e$e8g@server.cntfl.com> Sure would like to know the specs on this one, looks like: abt 6 in diameter, 4 foot long tube of fiberglass with a stacked set of tuned tubes inside. it checks out well at 146.00 at about 1.6 swr but I wold like to know more. thanks in advance for any e mail or post back here.. 73... KD4SEV lutzr@destin.nfds.net From amsoft@epix.net Sun May 12 18:01:46 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: 7 May 1996 06:31:00 -0700 Message-ID: <4mnjak$nkt@nnrp1.news.primenet.com> References: <4mf0ci$los@news.asu.edu> <4mhnqs$7tv@crash.microserve.net> <4mjl9j$805@nnrp1.news.primenet.com> <4ml4ni$dhr@itnews.sc.intel.com> <4mn4b3$5bl@crash.microserve.net> jackl@pinetree.microserve.com (WB3U) wrote: >Why doesn't MiniNec agree with this? I've tried a number of >theoretical combinations of frequency and lengths above 3/8 >wave. Like you say, the resistive component isn't too bad, >but the result often shows reactive impedances near 2,000 ohms >on one or more bands. Hi Jack, I didn't intend to disagree with MiniNec. If you take a Smith chart and draw two 450 ohm SWR circles, e.g. one at 3:1 and one at 20:1, the impedances from dipoles greater than 3/8 WL will lie outside the inner circle and inside the outer circle, a donut distribution of impedances. When the resistance is near minimum or maximum, the reactance is near minimum. When the resistance is mid-range, the reactance is high. A 50+j2000 impedance does not result in a "massive" SWR. As long as the dipole length is greater than about 3/8 WL, the resistance and reactance tend to follow a tracking pattern round and round inside the donut. When the dipole length becomes about 3/8 WL and less, the resistance and reactance stop tracking. The resistance goes down and down and the capacitive reactance goes up and up so you get impedances like 1-j5000 resulting in a "massive" SWR. The antenna impedance breaks out of the donut and heads for 0-j(infinity). I would define "massive" as an SWR greater than about 50:1 with 450 ohm ladder- line. If you thought I was disagreeing with MiniNec, we probably didn't agree on the definition of "massive" SWR. 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Sun May 12 18:01:46 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: 7 May 1996 16:56:01 -0700 Message-ID: <4monuh$jde@nnrp1.news.primenet.com> References: <4mo6m3$ijf@news.asu.edu> CHARLES J. MICHAELS wrote: : By the way I posted a correction to the posting you : referenced. I also calculated for 50 feet. Still less than : half reached antenna. Cecil says use a shorter line, and chooses : one. Hi Charlie, one can always build a taller house. :-) 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Sun May 12 18:01:48 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: Auto Tuner vs Multiband Vertical Date: Tue, 07 May 96 08:06:16 GMT Message-ID: <4mn4b3$5bl@crash.microserve.net> References: <4mf0ci$los@news.asu.edu> <4mhnqs$7tv@crash.microserve.net> <4mjl9j$805@nnrp1.news.primenet.com> <4ml4ni$dhr@itnews.sc.intel.com> Cecil Moore wrote: >Only below about 3/8 wavelength does the antenna impedance of a >dipole cause massive SWRs in a 450 ohm ladder-line fed system. >Longer than 3/8 wavelength, the 450 ohm SWR won't be higher than >about 20:1 giving a pure resistance at a current maximum of greater >than 22 ohms, not a bad match. Why doesn't MiniNec agree with this? I've tried a number of theoretical combinations of frequency and lengths above 3/8 wave. Like you say, the resistive component isn't too bad, but the result often shows reactive impedances near 2,000 ohms on one or more bands. 73, Jack WB3U From amsoft@epix.net Sun May 12 18:01:48 1996 From: "Anthony R. Gold" Newsgroups: uk.radio.amateur,rec.radio.amateur.antenna,rec.radio.amateur.misc Subject: Re: Beam Heading Info Date: Mon, 06 May 96 13:19:45 GMT Message-ID: <831388785snz@microvst.demon.co.uk> References: <831292354snz@microvst.demon.co.uk> <4mi8fo$l7m@tube.news.pipex.net> Reply-To: tgold@microvst.demon.co.uk In article <4mi8fo$l7m@tube.news.pipex.net> walt@servelan.co.uk "Walt Davidson" writes: > There is also a list along these lines in the RSGB > "Amateur Radio Operating Manual", with the origin at London, England. Thanks for this pointer and I'll follow it up. Maybe I'll also be told how to operate. It's must be about time I learned :-) Regards, -- Tony - G3SKR / AA2PM email: tgold@panix.com tgold@microvst.demon.co.uk packet: g3skr@n0ary.#nocal.ca.usa.na From amsoft@epix.net Sun May 12 18:01:49 1996 From: ad1c@tiac.net (Jim Reisert AD1C) Newsgroups: uk.radio.amateur,rec.radio.amateur.antenna,rec.radio.amateur.misc Subject: Re: Beam Heading Info Date: 11 May 1996 15:30:42 GMT Message-ID: <4n2br2$nv9@news-central.tiac.net> References: <831292354snz@microvst.demon.co.uk> <4mi8fo$l7m@tube.news.pipex.net> <4mn2gt$9hi@infa.central.susx.ac.uk> Reply-To: AD1C@tiac.net (Jim Reisert AD1C) E-mail me your latitude and longitude and I'll send you a printout in return E-mail. 73 - Jim AD1C -- Jim Reisert http://www.tiac.net/users/ad1c/ From amsoft@epix.net Sun May 12 18:01:51 1996 Newsgroups: rec.radio.amateur.antenna From: dgf@netcom.com (David Feldman) Subject: Re: Best Antenna for Apartment ? Message-ID: References: <4mluht$q1i@news.inforamp.net> <3190AA70.97D@arrl.org> Date: Wed, 8 May 1996 15:57:17 GMT In article <3190AA70.97D@arrl.org> Zack Lau writes: >Chris Valliant wrote: >> >> I live in a small apartment, but the landlord won't let me put an >> antenna on the roof. Does anyone know of a good antenna that I can mount >> on the window sill ? I have thought about putting up one without his >> knowledge, but that wouldn't be right. Any idea's would be greatly >> apreciated. Oh yea, this is for the 10 M band (forgot to add that in). > >The 10M band isn't in the best shape for DXing at this part of the >sunspot cycle, though you can work some surprising contacts if you >are patient and don't mind days on end without useful propagation. Try 75! I lived in an apartment in Southern California. _I_ didn't bother telling the landlord... I ran about 120' of fine guage wire out the window to the parking garage across the alley. Ran a KW phone. Lots of fun except when the window sill caught on fire a few times. Never did tell the landlord. All in fun, you see... 73 Dave WB0GAZ dgf@netcom.com From amsoft@epix.net Sun May 12 18:01:52 1996 From: gbishop@tc3net.COM (Gary Bishop) Newsgroups: rec.radio.amateur.antenna Subject: Coax or 450 ladder line Date: 6 May 96 13:45:58 GMT Message-ID: <19960506134557504.AAA74@LOCALNAME> I plan on building a 1/2 dipole for 12, 17, and 30. Going to have different wire lengths for each of the bands ie: 1/2 wave per band. Is there an advantage in using ladder line over coax or vice versa. Thank you. Brian Sarkisian KG8CO e-mail: gbishop@tc3net.com From amsoft@epix.net Sun May 12 18:01:53 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Coax or 450 ladder line Date: 7 May 1996 14:38:24 GMT Message-ID: <4mnn90$6bt@itnews.sc.intel.com> References: <19960506134557504.AAA74@LOCALNAME> gbishop@tc3net.COM (Gary Bishop) wrote: > > >I plan on building a 1/2 dipole for 12, 17, and 30. Going to have different >wire lengths for each of the bands ie: 1/2 wave per band. Is there an advant age >in using ladder line over coax or vice versa. Thank you. Hi Gary, If you don't understand transmission lines, IMO play it safe and use coax. If you do understand transmission lines, ladder-line has some definite advantages like the ability to transform impedances without appreciable losses. 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Sun May 12 18:01:53 1996 From: Richard Kiefer Newsgroups: rec.radio.amateur.antenna Subject: Re: Coax or 450 ladder line Date: Wed, 08 May 1996 20:16:56 -0700 Message-ID: <319163A8.382A@athena.csdco.com> References: <19960506134557504.AAA74@LOCALNAME> Gary Bishop wrote: > > I plan on building a 1/2 dipole for 12, 17, and 30. Going to have different > wire > > lengths for each of the bands ie: 1/2 wave per band. Is there an advantage in > > using ladder line over coax or vice versa. Thank you. > > Brian Sarkisian KG8CO e-mail: gbishop@tc3net.comHi Brian, I think you should definately use coax. I have found the commonly available ladder line to be VERY lossy with measurments on my HP network analyzer. Much more lossy than good quality coax. I do not know why everyone thinks balanced transmission line is so great. In addition, coax is probably more quiet, or less likely to pick up local magnetic coupled noise from computer monitors, motors, microprocessors in household applicances, etc. You can probably get away without a balun if you bring the coax off the center in a symetrical manner and do not have to much stuff around the antenna. Good luck. Dick Kiefer, K0DK From amsoft@epix.net Sun May 12 18:01:54 1996 From: blanton@ni.net (J. L. Blanton) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.space Subject: Coaxial and/or Counterwound Helix Antennas Date: Wed, 08 May 1996 22:42:30 -0800 Message-ID: I'm thinking about building some circularly polarized antennas for Oscar use (145 & 435 MHz). Has anyone tried installing a 435 MHz helix coaxially inside a 145 MHz helix? Or would there be too much interaction? In a related question, has anyone tried building counterwound helices for the same frequency band on a common framework for left and right circular polarizations (but separately fed, of course)? If anyone can point me to some references in these two areas I'd really appreciate it. Thanks. Lee, WA8YBT/6 From amsoft@epix.net Sun May 12 18:01:55 1996 From: moritz@ipers1.e-technik.uni-stuttgart.de () Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.space Subject: Re: Coaxial and/or Counterwound Helix Antennas Date: 10 May 1996 07:01:14 GMT Message-ID: <4mupjq$1sru@info4.rus.uni-stuttgart.de> References: >In a related question, has anyone tried building counterwound helices for >the same frequency band on a common framework for left and right circular >polarizations (but separately fed, of course)? Lee, For the same amount of material / weight / wind load a cross yagi is better. 73, Moritz DL5UH From amsoft@epix.net Sun May 12 18:01:57 1996 From: dnorris@k7no.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Thu, 09 May 1996 00:13:56 GMT Message-ID: <4mrdb5$8ca@news.syspac.com> References: <4mg9ar$l77@crash.microserve.net> <4mlflb$rde@suba01.suba.com> <318FF9EB.211C@erols.com> Jake Brodsky wrote: >byoung@qni.com wrote: >> >> Jack, >> >> I *HAD* a mole problem. I rectified it with several cheap >> battery-powered AM radios. >> >> #1 Tune them to a local rock station with a good signal. >> (needs to be rock-n-roll, moles like classical and country) >> #2 Turn 'em up fairly loud. >> #3 Stick 'em in heavy plastic bags. >> #4 Bury them where you have the problem. >> >> The batteries usually last a week or more, and by then the moles >> have "moved on" to greener pastures. Sounds silly, but it works! >> >> Bill Young >> byoung@qni.com >> KB0UZQ >Where are the smileys? Assuming the small chance that you're serious, >have you tried this? What did your neighbors think? And please tell >us what gave you the notion to try such a silly thing! I wonder if >People for the Ethical Treatment for Animals has anything to say about >this... :-> >Jake Brodsky, AB3A, >"Beware of the massive impossible!" I was fighting gophers (not the Minnesota type) for a long time. PETA found out that I has caused the demise of some small number of these critters and have forced me to pay retribution. This comes in the form of gopher food, scientifically tested for flavor and growth advantage, Now the gophers walk into the house and demand fresh cut veggies and Iced tea (Arizona style). Getting hard to cope..... C. Dean Norris Amateur Radio Station K7NO e-mail to dnorris@k7no.com http://www.syspac.com/~dnorris/ From amsoft@epix.net Sun May 12 18:01:58 1996 From: aor Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Wed, 08 May 1996 12:19:29 -0400 Message-ID: <3190C991.21@gteais.com> References: <4mg9ar$l77@crash.microserve.net> WB3U wrote: > > Lately, I've been thinking about stringing a wire vertical from > a tree and installing a good radial system underneath. However, > there's a wildlife problem that's threatening to thwart my plans. > > During the last two winters, I have been beseiged by an invasion > of moles. The runners they create in the yard and the many mole > hills make it impossible to consider radials. I still have to > cut what's left of the grass, and there's no question that the > moles' activity will push any wires I install up to the surface. > > So far I've tried the following with little or no success: > > Smoke bombs and poison pellets designed for this purpose > Traps designed to kill the mole when it tunnels underneath > Flooding the tunnels with a garden hose > Filling the tunnels with exhaust fumes from my car > 900 VAC at 1 Amp delivered into the ground by aluminum stakes > placed 20 feet apart > Elmer Fudd impressions (lawn chair and shotgun) There has been significant modeling which shows that an elevated radial system of 4-6 wires up can give you the same performance as a 64 burried wire field. On 80 meters, the radials need only be up 15' feet, slightly less for the higher bands. The radials are tuned, (ie 1/4 wave + 5%), and you have have multiple bands. I do not know what your tree-field looks like, but 4-6 elevated radials up 10' or so may fit the bill, and keep the critters at bay!!! 73, Al NW2M From amsoft@epix.net Sun May 12 18:02:00 1996 From: shssci@li.net Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Thu, 09 May 96 13:05:00 PDT Message-ID: References: <4mg9ar$l77@crash.microserve.net> <4mlflb$rde@suba01.suba.com> In Article<4mlflb$rde@suba01.suba.com>, write: > Path: li.net!news5.ner.bbnplanet.net!news.ner.bbnplanet.net!howland.reston.a ns.net!news.cac.psu.edu!news.math.psu.edu!chi-news.cic.net!news.suba.com!news > From: byoung@qni.com > Newsgroups: rec.radio.amateur.antenna > Subject: Re: Critters > Date: 6 May 1996 18:16:11 GMT > Organization: Suba Communications > Lines: 17 > Message-ID: <4mlflb$rde@suba01.suba.com> > References: <4mg9ar$l77@crash.microserve.net> > NNTP-Posting-Host: 206.29.114.19 > X-Newsreader: SPRY News 3.03 (SPRY, Inc.) > > Jack, > > I *HAD* a mole problem. I rectified it with several cheap > battery-powered AM radios. > > #1 Tune them to a local rock station with a good signal. > (needs to be rock-n-roll, moles like classical and country) > #2 Turn 'em up fairly loud. > #3 Stick 'em in heavy plastic bags. > #4 Bury them where you have the problem. > > The batteries usually last a week or more, and by then the moles > have "moved on" to greener pastures. Sounds silly, but it works! > > Bill Young > byoung@qni.com > KB0UZQ Be careful - I tried this once - it did eliminate the moles, but I found my lawn infested with teenagers... :-) KD2FT From amsoft@epix.net Sun May 12 18:02:00 1996 From: lweissma@motown.ge.com (Larry M. Weissman, X6946) Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: 8 May 1996 21:40:43 GMT Distribution: world Message-ID: <4mr4cr$m0o@cnn.motown.lmco.com> References: <318C5813.34A4@ro.com> Reply-To: lweissma@motown.ge.com John D. Farr wrote: > I have a cat that has developed a taste for moles. I have no problems >with them like some of my neighbors. Best of all, my cat brings me the >best parts! >73, John Can I rent your cat for a weekend John? Larry - AD3Y From amsoft@epix.net Sun May 12 18:02:01 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna Subject: Re: Diamond 2m 5/8 mobile antenna (for so239 mount) Date: 10 May 1996 18:42:46 GMT Message-ID: <4n02n6$56e@news.service.uci.edu> References: <3193638B.3CAB@yvv.com> In article <3193638B.3CAB@yvv.com>, sbasile@yvv.com says... >Hi: Does anyone know who manufacturers the Diamond 2m 5/8 mobile whip >with the pl 239 fitting. ... text cut here ... >Thanks, >Sal Sal, Diamond is the manufacturer (or distributor for US market) from Japan. Most Diamond, Comet, and some Anli antennas are made to fit the SO-239 connector mounts. H.R.O. and R.E.S. and most ham radio stores sell these products. If you can not find a store near you, then let me know and I'll give you an address and phone number of several stores when I get home. Brian From amsoft@epix.net Sun May 12 18:02:03 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: Wed, 08 May 96 19:15:16 GMT Message-ID: <4mqrpu$6ov@nadine.teleport.com> References: <95849@gate.kc5aug.ampr.org> <4mg98q$l77@crash.microserve.net> <4mp7ga$3vh@crash.microserve.net> In article <4mp7ga$3vh@crash.microserve.net>, jackl@pinetree.microserve.com (WB3U) wrote: >I'm confused. Two people have mentioned that my reply to the dipole >inquiry was incomplete/incorrect because A) the 2.13 dBi dipole is >only theoretical, and B) the 2.13 dBi dipole is in free space. > >So, I went back and looked at my post. This is what I found: > >>This will create a dipole, although with certain deviations from >>a theoretical model due to practical considerations. > >>the gain will vary with height above ground and soil conditions. > >Was there something about the way I structured my reply that >caused these statements to be overlooked? > >73, >Jack WB3U Your statements weren't overlooked; speaking as one of the posters in question, I just felt that an adequate explanation required more elaboration. A dipole in free space has a gain in its best directions of about 2.15 dBi. If a ground is placed under it, several important (interrelated) things happen. First, the average strength of the entire field increases 3 dB because the energy is now concentrated in a hemisphere rather than being radiated in all directions. Second, energy reflects from the ground and adds to the energy being radiated directly, modifying the pattern and gain. Third, the feedpoint impedance of the antenna changes because of interaction of the field with ground. This in turn changes the strength of the field from the antenna. The net result is a field strength which is several dB greater than that of a free-space dipole (and a very different pattern), for any antenna height over ground of any real conductivity. And, unless you're miles above the Earth, any dipole you construct will be over ground, not in free space. To me, these constitute major differences between a dipole in free space and one over ground, more than "certain deviations. . due to practical considerations" and "[variation] with height above ground and soil conditions". I apologize if I misinterpreted your statements. Roy Lewallen, W7EL From amsoft@epix.net Sun May 12 18:02:03 1996 From: jjo@tekla.fi (Jari Jokiniemi) Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: 09 May 1996 04:38:10 GMT Message-ID: References: <4mmj1n$6kg@news.asu.edu> Well, there is no such thing as a 2.15 dBi dipole in the real world of amateur HF communications due to the ground which we can not get rid off. So what? Let us compare the dipole and a 7 dBd yagi over the real ground at the same height. That yagi does indeed beat the dipole with the great margin of 7 dBd. Who cares how much the gain is in dBi? -- Jari Jokiniemi, jari.jokiniemi@tekla.fi, OH2MPO, OH3BU Tekla Oy, Koronakatu 1, 02210 Espoo, 90-8879 474 From amsoft@epix.net Sun May 12 18:02:04 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: 10 May 1996 05:18:02 GMT Message-ID: <4mujia$lc@news.asu.edu> Jari said - Jari said - That yagi does indeed beat the dipole with the great margin of 7 dBd. Who cares how much the gain is in dBi? Jari, If it is understood that you are only comaring the gain at the peak of the lobe then there is no problem. But when you start to compare other pattrts/// parts of the pattern, it is not always clear whether you are comparing those parts with the dipole pattern parts at the same coordinates or if you are referenceing it to the peak of the dipole lobe. Charlie, W7 XC -- From amsoft@epix.net Sun May 12 18:02:05 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Electric half-wavelenght xmition....re:... Date: 6 May 1996 18:52:43 GMT Message-ID: <4mlhpr$nct@itnews.sc.intel.com> References: <27988@SP-gw.ampr.org> py3crx@sp-gw.py2bjo.ampr.ORG wrote: >At least the intention is to shield the path between >the transmatch and antenna - the neighbours will love it!. Hi Marcus, I can't tell if your antenna is balanced or unbalanced, resonant or non-resonant. Your intended shielding will probably be achieved with a resonant half-wave dipole fed by coax with a 1:1 balun at the antenna. If your antenna plus balun is not perfectly unbalanced, you will likely get feedline radiation. If your antenna is non-resonant, you will likely lose a lot of power in the coax due to reflections. It's just not a good idea to use coax on a non-resonant length antenna. 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Sun May 12 18:02:06 1996 From: "John C. Sanders" Newsgroups: rec.radio.amateur.antenna Subject: External Antenna for Nokia Handheld Cell Phone on Sailboat? Date: Tue, 07 May 1996 19:52:16 -0700 Message-ID: <31900C60.2B93@westnet.com> My boss has a Nokia handheld cellular phone and a sailboat he likes to sail in and around Casco Bay, Maine. The cell phone is 1.6 watts. He's asking me if he can attach an external antenna to this phone, the antenna to be mounted at some suitably high spot, like maybe atop the mast. We believe that there may be a so called car kit available for the phone that includes an external antenna connector (BNC). Question: Will the installation of the antenna atop the mast and connected to the phone via cable provide improved reception or would this be a waste of time and money unless he also went for a 3 watt booster kit. The point is he has this phone and doesn't want to get another phone (account) just for the boat. Thanks, John From amsoft@epix.net Sun May 12 18:02:07 1996 From: Darrell Barabash Newsgroups: rec.radio.amateur.antenna Subject: Re: Familiar with this antenna book? Date: Sat, 11 May 1996 23:29:12 -0500 Message-ID: <31956918.2E88@iamerica.net> References: <4msfs7$4e4@news.dx.net> KC8CGX wrote: > Anyone familiar with this book: "Antenna Engineering > Handbook, Second Edition", Ed by R.C. Johnson & H. Jasik, > pub by McGraw-Hill. This is a very good, practical book that covers many types of antenna systems. It gets into the theory but not too deep. You can get it for $12.95? Don't even give that a second thought -- get it. At full retail it's more than worth it. From amsoft@epix.net Sun May 12 18:02:08 1996 From: Jack McClain Newsgroups: rec.radio.amateur.antenna Subject: Re: Field Day wire antenna hints needed Date: Tue, 07 May 1996 07:44:43 -0400 Message-ID: <318F37AB.CCE@radio.org> References: <3184ABA0.41C67EA6@plhp002.comm.mot.com> <3186C786.7415@radio.org> <4mlgmf$fdm@huron.eel.ufl.edu> John Hughes wrote: > > > For a number of years our Field Day stations consisted of erecting > > tri-band beams on portable 75 foot towers for the high bands and various > > dipoles or double extended Zepps for 40 and 80 Meters...even tried a > > G5RV one year! > > > > BUT - the last three years we've abandoned those antennas in favor of > > Horizonal loops. (I should have started with the fact that we operate in > > class 2B - One SSB station and one CW station) > > > > It's so simple if you have any sort of supports to put up as big a loop > > as you have room for and as high as you can get it. Works well even at > > 25 feet. We feed ours with 450 ohm ladder line and use a tuner > > (Transmatch) to match the transceiver. This antenna works well on all > > bands, so well we don't even miss the beam for 10-15-20. > > > > 73, Jack ae4q@radio.org > > Loops/ladderline sound gud, but tell us where did you all get the 75ft > portable towers???? > > 73 Surplus trailer-mounted fold-over 75' towers! Originally used for microwave site selection tests for microwave routes. Fiber Optics technology had made the towers surplus! 73, de AE4Q From amsoft@epix.net Sun May 12 18:02:09 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna Subject: Re: Field Day wire antenna hints needed Date: 10 May 1996 18:31:38 GMT Message-ID: <4n022a$56e@news.service.uci.edu> References: <4mlgmf$fdm@huron.eel.ufl.edu> <4mlu8q$mk3@news1.t1.usa.pipeline.com> <31924A46.1E6A@cellnet.com> In article <31924A46.1E6A@cellnet.com>, jdd@cellnet.com says... >Not exactly in My ham budget! >Cheers. >Jim, WU0I >ke6ber@usa.pipeline.com wrote: >> In article <4mlgmf$fdm@huron.eel.ufl.edu>, John Hughes writes: >> >Loops/ladderline sound gud, but tell us where did you all get the 75ft >> >portable towers???? >> >73 I have a friend with a military style guyed crank up that's about 50ft. I'd buy it myself but really can't justify it to my wife. If you or a club is interested, the cost is almost 1/10 the 75ft unit mentioned earlier. Brian From amsoft@epix.net Sun May 12 18:02:10 1996 Newsgroups: rec.radio.amateur.antenna From: Marilyn Swartz Subject: FM Antenna Question Message-ID: <318F1AD9.622A@sfusd.sf.ca.us> Date: Tue, 07 May 1996 02:41:45 -0700 Sorry that this isn't a question about esoteric antenna theory, but here goes: I recently bought an R-95 Yamaha receiver to listen to FM stations. I am using the simple wire-loop antenna that came with the receiver. However, as I live very close to a radio tower (Sutro tower in San Francisco), it is very difficult to get certain stations because of the interferance--they come in, but with a lot of static and only after moving the antenna around a lot. Would getting a better antenna help, and if so, which one? The people at Good Guys, where I bought the receiver, only reccommend the Terk brand antennas they have availiable. I would prefer to use an indoor antenna if possible, however--but it seems that my problem is mainly antenna selectivity, not sensitivity, so I doubt a large antenna would do anything. Thank you very much in advance for your help. From amsoft@epix.net Sun May 12 18:02:11 1996 From: mikef@shadow.net (Mike Fink) Newsgroups: rec.radio.amateur.antenna Subject: Help on cutting radials for 225-400Mhz,what length? Date: 6 May 1996 22:06:32 GMT Message-ID: <4mlt58$1hn@viper.shadow.net> I bought a quarterwave groundplane from RS and want to trim the 3 radials and 1 vertical element for monitoring military air. Can someone recommend a good length to trim them too,and what frequency is best to use 225,300,400Mhz in choosing the length. Thanks Mike -- -------------------------------------------------------------------------- |Mike Fink Support the right to bear arms | |mikef@shadow.net | |http://www.shadow.net/~mikef | -------------------------------------------------------------------------- From amsoft@epix.net Sun May 12 18:02:12 1996 From: ke6ber@usa.pipeline.com Newsgroups: rec.radio.amateur.antenna Subject: Re: HF Vertical Date: 6 May 1996 22:22:46 GMT Message-ID: <4mlu3m$mfn@news1.t1.usa.pipeline.com> References: <318E30B4.49E4@aa6g.org> In article <318E30B4.49E4@aa6g.org>, Chuck Vaughn writes: >George J. Molnar wrote: >> >> Dan Tang wrote: >> > >> > Can some one please tell me if an hf vertical antenna install on the roof >> > (with radials) works as good as it install on the ground (with radials)? >> >> It'll probably work a bit better, presuming you install a good-quality >> set of radials on the roof. > >And not only that, but you can get the impedance closer to 50 ohms >by sloping the radials down. > >Chuck - AA6G I used to have a Cushcraft AP8A mounted on my chiney. I had VERY good luck with it. Good performance for both domestic and DX contacts. Really enjoyed it. Good luck. Al, KE6BER/1, KE6BER@usa.pipeline.com From amsoft@epix.net Sun May 12 18:02:14 1996 From: Garth Wiscombe Newsgroups: rec.radio.amateur.antenna Subject: Re: HF Vertical Date: 9 May 1996 02:03:21 GMT Distribution: world Message-ID: <4mrjp9$atm@NEWSnewsNeWsnEwS> References: <318E30B4.49E4@aa6g.org> <4mlu3m$mfn@news1.t1.usa.pipeline.com> To: ke6ber@usa.pipeline.com ke6ber@usa.pipeline.com wrote: >In article <318E30B4.49E4@aa6g.org>, Chuck Vaughn writes: > >>George J. Molnar wrote: >>> >>> Dan Tang wrote: >>> > >>> > Can some one please tell me if an hf vertical antenna install on the >roof >>> > (with radials) works as good as it install on the ground (with >radials)? >>> >>> It'll probably work a bit better, presuming you install a good-quality >>> set of radials on the roof. >> >>And not only that, but you can get the impedance closer to 50 ohms >>by sloping the radials down. >> >>Chuck - AA6G > >I used to have a Cushcraft AP8A mounted on my chiney. I had VERY good luck >with it. Good performance for both domestic and DX contacts. Really >enjoyed it. Good luck. >Al, KE6BER/1, KE6BER@usa.pipeline.com > Just a note: You may want to check with the manufature of your particular vertical to see if the radials are longer with the roof top mount than the ground mounting. For example I have the AV5 and the radials for the 80 meter band are 6 feet longer for the roof mount than ground. My installation instructions came with the information for both ground and roof mounting. The comment of coming closer to 50 ohms because of angle are also very true and are discussed in brief in the installation instructions that I have for my antenna. Have Fun. -- ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ * * * * * Garth Wiscombe, KA7MHN /\ /\ * * / / / Office 801 265-5057 Salt Lake City / \/ \ /\ ----/\--- Cellular 801 631-8675 Utah 84119-6032 /\ \ \ \ / / || / Home 801 967-3236 USA / \ \ \ \ || FAX 801 967-3268 / \ \ \ \ || E-mail garth@alinc.com 73 de Garth KA7MHN ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ From amsoft@epix.net Sun May 12 18:02:15 1996 From: Siegfried Rambaum Newsgroups: rec.radio.amateur.antenna Subject: Re: High SWR Help Date: Fri, 10 May 1996 14:52:42 -0400 Message-ID: References: <000006850000303E@nashville.com> On 8 May 1996, Steve Lee wrote: > Here's what he's doing. He has a Cobra 148F and a Firestik 2 antenna. Humm ... this sounds, as if your friend only installed half the antenna. The other half of that antenna would be the car; the Firestick and the car give a complete antenna system (i.e. form a groundplane) .... I guess, he would need to add radials like it is the rule for each decent groundplane. > He can't have an outdoor antenna where he is at. So, he mounted the > antenna in his attic. The antenna is 3 feet tall just below his roof > inside the attic. He's using 50 feet of RG58 coax , new from Radio > Shack. This is a mobile style antenna, but he is using his radio as a base ******************** here you say it yourself... From amsoft@epix.net Sun May 12 18:02:16 1996 From: halbert@bbn.com (Dan Halbert) Newsgroups: rec.radio.amateur.antenna Subject: Re: Horizontal HF loops Date: 6 May 96 21:17:17 GMT Message-ID: References: <317CF945.31D2@ldp.com> <4lteku$6aq@consolidated.ccinet.net> <4mfqhj$ijd@everest.vol.it> <4mjua9$n3f@nnrp1.news.primenet.com> >[Continuing a thread about how good horizontal loops are] >... Only reason I don't still have it up is that the >...trees kept rubbing thru the wire and I got tired of fixing it. I have held up my loops by running the wire (12/13 gauge solid or stranded copper) through stainless steel marine pulleys that have nylon wheels. They don't rust, and the wire is free to slide back and forth in the wind. The pulleys themselves are held up by nylon cord over tree limbs. It can be a nuisance to thread the wire through all the pulleys. Some marine pulleys have removable wheels (sheaves?). On others I have drilled out the rivet that holds the wheel and replaced it with a stainless bolt and nut. Dan Halbert, KB1RT From amsoft@epix.net Sun May 12 18:02:18 1996 From: P Tyers Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew Subject: Re: HOW DO U CONNECT COAX TO QUAD???????? Date: Fri, 10 May 1996 14:08:58 +1100 Message-ID: <3192B34A.6EF1@trl.oz.au> References: <318c1477.108916@news.atl.mindspring.com> Monty Wilson wrote: > > billp8@atl.mindspring.com (Bill Poston) wrote: > >I am attempting to homebrew a quad antenna. I have read Cubical Quad > >Antennas by W6SAI and the ARRL Antenna Book. Neither answers my question. > > > >How do I connect one coax feedline to the multiple loops on the driven > >element? > > > >Please explain in detail so that a dummy can understand. > Have another read of Cubical Quads. What you actually end up doing is producing a multiple gamma match, one for each loop. Of course they interact to all heck while being adjusted.I seem to recall that the preferred order of adjustment was from smallest loop to largest loop for minimum interaction - BUT I COULD BE TOTALLY WRONG ON THIS. Another source of information is a series of articles published in the Wireless Institute of Australia magazine "Amateur Radio" about 15 +/- 5 years ago on multiband quads which had several column inches on the care and feeding of these gamma matches. Hope this helps! -- P Tyers, Tel. +61-(0)3-92536794 AARnet: p.tyers@trl.telstra.com.au CSnet: p.tyers@trl.oz.au HAM: VK3KTS MAIL: Telstra Research Laboratories,P.O. Box 249, Clayton,VICTORIA 3168,AUSTRALIA From amsoft@epix.net Sun May 12 18:02:20 1996 From: mluther@tamu.edu Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew Subject: Re: HOW DO U CONNECT COAX TO QUAD???????? Date: 11 May 1996 05:45:45 GMT Message-ID: <4n19i9$ie4@news.tamu.edu> References: <318c1477.108916@news.atl.mindspring.com> <3192B34A.6EF1@trl.oz.au> Reply-To: mluther@tamu.edu In <3192B34A.6EF1@trl.oz.au>, P Tyers writes: >Monty Wilson wrote: >> >> billp8@atl.mindspring.com (Bill Poston) wrote: >> >I am attempting to homebrew a quad antenna. I have read Cubical Quad >> >Antennas by W6SAI and the ARRL Antenna Book. Neither answers my question. >> > >> >How do I connect one coax feedline to the multiple loops on the driven >> >element? >> > >> >Please explain in detail so that a dummy can understand. >> > >Have another read of Cubical Quads. What you actually end up >doing is producing a multiple gamma match, one for each loop. >Of course they interact to all heck while being adjusted.I >seem to recall that the preferred order of adjustment was >from smallest loop to largest loop for minimum interaction - >BUT I COULD BE TOTALLY WRONG ON THIS. > > Another source of information is a series of articles >published in the Wireless Institute of Australia magazine >"Amateur Radio" about 15 +/- 5 years ago on multiband quads >which had several column inches on the care and feeding of >these gamma matches. > >Hope this helps! > >-- >P Tyers, Tel. +61-(0)3-92536794 >AARnet: p.tyers@trl.telstra.com.au >CSnet: p.tyers@trl.oz.au HAM: VK3KTS >MAIL: Telstra Research Laboratories,P.O. Box 249, > Clayton,VICTORIA 3168,AUSTRALIA You're right on target! Highest to lowest frequency. It takes some juggling. However, once done, the match stays done. I've used the gamma match feed system on quads (and virtually everything else I can reasonably adapt it to. It works on the quads VERY well. Another tip. In stead of chasing all over heck and back for big variable capacitors as you get down to 40 and 80 meter quads, use a chunk of RG-8 coax cable as a capacitor. It has capacity and a nice hefty dialectric that will let you use the inner conductor as one arm of a capacitor and the outer shield as the other arm. You get it too long by a foot or so for the total capacity you need. You whackem off an inch or so at a time at lower power to trim away the capacitance. You use a much smaller air variable for the trimmer. When done, presto, BIG heavy cap for 40 and 80 meter versions heap cheapo. Be sure to trim away some of the braid and leave an inch or so of the inner conductor and insulation extended to avoice arcing at high power.... Tape the end up to excude water. Smile all the way to the bank. :) Mike W5WQN as a guest at leviathan.tamu.edu (No mail address there) From amsoft@epix.net Sun May 12 18:02:21 1996 Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew From: "Al Koblinski (W7XA)" Subject: Re: HOW DO U CONNECT COAX TO QUAD???????? Message-ID: To: billp8@atl.mindspring.com References: <318c1477.108916@news.atl.mindspring.com> Date: Thu, 9 May 1996 23:56:14 GMT I use a 1:1 balun for each loop (Bencher, but any brand is OK). Where needed I used a coax matching section to match. On 20mtr, my 3 el on 26' boom was 49 ohms so no matching was needed for 50 ohm coax. Ditto for 5 el on 15 mtrs with same boom. 10 meters, 5 elements came out to near 90 ohms impedence and I used a section of 75 ohm coax between the balun and the 50 ohm feedline. Each element is fed seperately through a switchbox. I have used a variety of other feed methods in the past, such as gamma matching (cumbersome) and found that the simple balun approach works great and is mechanically the most simple. 73, Al From amsoft@epix.net Sun May 12 18:02:22 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: ISOTRON Antenna Information Date: 8 May 1996 14:15:21 GMT Message-ID: <4mqa9p$c2@itnews.sc.intel.com> References: <4mogau$mh9@clark.zippo.com> blazar@ea.net wrote: >Any information will be greatly apreciated. TIA. Hi Barry, IMO you would be a lot better off running $10 worth of wire in your attic. Have you seen any radiation efficiency specs on the Isotrons? 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Sun May 12 18:02:23 1996 From: blazar@ea.net (Barry LaZar) Newsgroups: rec.radio.amateur.antenna Subject: Re: ISOTRON Antenna Information Date: Thu, 9 May 1996 06:34:43 +1000 Message-ID: References: <4mogau$mh9@clark.zippo.com> <4mqa9p$c2@itnews.sc.intel.com> In article <4mqa9p$c2@itnews.sc.intel.com> Cecil Moore writes: >From: Cecil Moore >Subject: Re: ISOTRON Antenna Information >Date: 8 May 1996 14:15:21 GMT >blazar@ea.net wrote: >>Any information will be greatly apreciated. TIA. >Hi Barry, IMO you would be a lot better off running $10 worth of >wire in your attic. Have you seen any radiation efficiency specs >on the Isotrons? >73, Cecil, KG7BK, OOTC (not speaking for my employer) > Cecil, Thanks for the response. All I know about the antenna(s) is what I have read in a couple of 73 articles. 73 /Barry, K3NDM From amsoft@epix.net Sun May 12 18:02:23 1996 From: Erik Finskas OH2LAK Newsgroups: rec.radio.amateur.antenna Subject: Looking for a 50MHz/145MHz dualband GP Date: Tue, 07 May 1996 17:07:26 +0100 Message-ID: <318F753E.73FE@ee.port.ac.uk> Is there available any ground plane antennas for 50MHz/145MHz?? Or if you have building instructions, how to make one, could you please mail me! Erik -- Erik Finskas M1AAJ & OH2LAK Email Finskase@ee.port.ac.uk Lakki@clinet.fi University of Portsmouth, UK Department of Electric and Electronic Engineering From amsoft@epix.net Sun May 12 18:02:26 1996 From: p.sanders@groupz.net (Mica Sanders) Newsgroups: rec.radio.amateur.antenna Subject: Re: Mobile Antenna for 27Mhz Date: Tue, 07 May 1996 20:12:39 +0300 Message-ID: References: <4kpti6$jmd@news.ios.com> <317E5AD3.3483@gteais.com> <4lsa7q$ld7@news.ios.com> In article <4lsa7q$ld7@news.ios.com>, brianv1@village.ios.com wrote: > aor wrote: > >brianv1@village.ios.com wrote: > >> > >> I am trying to build a beam type of antenna for a 27Mhz mobile. Does > >> anyone have any models of this or ideas??? Even if you have formulas or > >> theory I would be very interested. > >> > >> Thanks > > > > > >One of the easiest ways to do this is by using two > >antennas and phasing them. One example would be to > >buy two 9' whip antennas and mount them 9' feet > >apart (1/4 wave on 27 MHz). Feed them in phase by > >using two equal runs of (odd 1/4 wave) 75 ohm coax > >from a tee-connector on your radio. The pattern > >will be broadside to the two antennas. With about > >3db of gain over a single antenna. > > > >You see truck drivers with two antennas, you don't > >see the phasing harness, and the pattern favors the > >front and back (broadside) by 3 db (double your > >radiated power) at the expense of side radiation > >(end-fire). The principles are the same. > > > >There are a lot of other things to consider > >assuming you can put two antennas 9' apart on a > >car, have good grounding, and a good ground plane. > >There are other methods by using 90 degrees phasing > >and 1/4 wave spacing... but that is another story. > >This resembles a 2-3 element beam pattern. > > > >It is a lot of fun to do, 75 ohm coax is cheap, and > >one centrally mounted antenna is usually better > >than multiple antennas for 99% of the population. > >Besides, how did you plan on turning this "beam" > >??? Hi Hi > > > >For 30 bucks, order the ARRL Antenna Handbook and > >read up on the subject. > > > >See ya, > > > >Al NW2M > > Thanks for the info. I'll look into that. I had heard that you can make > one of the antennas the hot and another the ground or backdoor. > Suppossedly the backdoor should act like a reflector. Al, I invested in the ARRL Antenna Book (several years ago) and (IMHO) found it to be of minimal value except in low band antenna designs. It is sorely lacking in phasing harness design and applications. I have yet to find a formula (or person) to describe how Decibel Products (premier supplier of commercial antennas) phases multiple folded dipoles (as many as 16 on UHF). I built an 8 dipole 465 MHZ unit using a DB-420 as a model and it performed exceptionally well (VSWR 1.05). I did not consider frequency/cable Velocity factor when building the harness but made sure that all 8 elements were fed using equal line lenghts from the feedpoint (total of 7 "tees" including feedpoint which was positioned at the center of the array). IMHO, it would seem logical that if the RF signal arrived at each element at the same time, all elements would resonate "in-phase" and the way to accomplish this is by equal lenghts of coax to each element from the feedpoint. Could you lend some insight on why the cable lenghts have to be in multiples of the frequency (even if center fed?), and what the "odd multiple" does for the design? Thanks, Paul WNQN319 From amsoft@epix.net Sun May 12 18:02:27 1996 From: micro@prometheus.hol.gr (George Micros) Newsgroups: rec.radio.amateur.antenna Subject: Need help! Fm Antenna and dipole construction. Date: 10 May 1996 00:52:48 GMT Message-ID: <4mu410$5ir@newsflash.hol.gr> I am looking for any plans for an FM Antenna or co-linear antenna with at least four dipoles. Need dipole distances and anything that might help me build it, (mathematical types will do). For use with a 500W fm transmitter. (for now). Any help will be appreciated. If possible please e-mail me at micro@prometheus.hol.gr From amsoft@epix.net Sun May 12 18:02:28 1996 From: moritz@ipers1.e-technik.uni-stuttgart.de () Newsgroups: rec.radio.amateur.antenna Subject: Re: PVC Core to build 2.4Ghz loop yagi? Date: 7 May 1996 08:10:44 GMT Message-ID: <4mn0i4$2fse@info4.rus.uni-stuttgart.de> References: In article , Mick Henniger wrote: >The word around here is that ~ 24 db gain is required of the antenna Well, a miror of abt. 4 feet in diameter will get you there. worth considering. >1. Loop yagi build on 1.5 inch diameter PVC pipe. > Dimensions scaled from 1.2Ghz loop yagi in VHF/UHF handbook. > Not placed on metal boom, just the PVC. The problem is the scaling. since all dimensions are interdependent, there is a fair chance that it will not work in the end. Better to find a 2.3 GHz design. >2. Helical antenna, wound on 1.5 inch diameter PVC pipe. > Dimensions scaled from 1.2Ghz helical antenna in VHF/UHF handbook. > No center support, just the PVC. You can test the PVC in the microwave oven. Some are lossy and some are not. There will also be some detuning by the dielectric constant For the same gain a loop yagi is more compact. > How do I match 140 <--> 75? use two antennas paralell. one can be righthand and the other lefthand to get vert. pol. >3. A collinear which is must a vertical wire with stubs (1/4 wave out and > 1/4 wave back) every half wavelength. with 24 dB?? 73, Moritz DL5UH From amsoft@epix.net Sun May 12 18:02:29 1996 From: lavallee@island.net (Gerry Lavallee) Newsgroups: rec.radio.amateur.antenna Subject: Question-railroad antennae Date: 10 May 1996 04:38:44 GMT Message-ID: I was wondering if someone could enlighten me. I am a rail fan and have noticed different radio antennae on locomotives. I am curious why different shapes are required as the frequencies used by railroads are in the same bandwidth (around 160 megahertz) I understand how a "whip" antenna radiates out a signal & captures a signal. I have an idea why a base plane is used underneath a whip antenna. Anyway, in the past & now in the present I have seen; 1. An antenna shaped like a gong type bell 2. " " " " a railing along the loco hood (induction?) 3. " " " " a fire cracker 4. " " " " an ice skate (called "Sinclair" type) 5. " " " " a tin can The Sinclair type is almost universally used in Canada but in the states the antennae used seem almost random, even on the same railroad From amsoft@epix.net Sun May 12 18:02:30 1996 From: "Michael C. Maguire" Newsgroups: rec.radio.amateur.antenna Subject: Request for Info on M2 Antenna Controller Date: 7 May 1996 18:48:39 GMT Message-ID: <4mo5u7$lme@client2.news.psi.net> I have a Model RC2800-PRK Dual Controller from a company called M2 or M-square d (depending on how you read the logo). The controller connects to an az/el mount suitable for coarse pointing of a helical antenna for satellite tracking . Unfortunately, I do not have a complete manual set for either the controller o r the az/el drives. Does anyone have contact information for either M2 or a sales rep for M2? Any combination of corporate address, phone, fax, email or WWW address would be appreciated. Thanks in advance. Regards, mcm -- Michael C. Maguire Systems Engineer Earthwatch Inc. - http://www.digitalglobe.com/ Tel: 510-417-2044 Fax: 510-417-2045 Email: mmaguire@ewi.com From amsoft@epix.net Sun May 12 18:02:30 1996 Newsgroups: rec.radio.amateur.antenna From: ao779@torfree.net (CB Smith) Subject: Rogers Antenna System Message-ID: Date: Sun, 12 May 1996 00:19:19 GMT Does anyone have details on this antenna ? Apparently built by the US military in the 1930's and is static-free. Any ideas ? de Brian ve3ex ao779@torfree.net From amsoft@epix.net Sun May 12 18:02:31 1996 From: Clint.Bradford@bbs.woodybbs.com (Clint Bradford) Date: 07 May 96 19:38:00 Newsgroups: rec.radio.amateur.antenna Subject: Sale Message-ID: <6b0_9605080929@woodybbs.com> >>Hi Tom here... I have for sale 2 Regency 16ch programable mobiles. INTERNET TIP #4 - If the Conference/Newsgrou doesn't have the word, "SALE," in its title, it is probably inappropriate to post FOR SALE messages in it. There -IS- a very active FOR SALE area for you on the same system you posted this message. Please prepare for a little flack from those who will not-as-gently-as-I-have remind you of the Conference Posting rules. clint.bradford@atdbbs.com ... ATTENTION to Details BBS - 909-681-6221 - REACT/GMRS/AMATEUR RADIO --- * TLX v4.00 * * wcECHO 4.1 ~ AR-Net: ATTENTION to Details * Mira Loma, CA * 909-681-6221 -- |Fidonet: Clint Bradford 1:2619/228 |Internet: Clint.Bradford@bbs.woodybbs.com | | Standard disclaimer: The views of this user are strictly his own. From amsoft@epix.net Sun May 12 18:02:32 1996 From: billv21572@aol.com (BillV21572) Newsgroups: rec.radio.amateur.antenna Subject: Re: shortend radials Date: 9 May 1996 02:02:45 -0400 Message-ID: <4ms1q5$7dp@newsbf02.news.aol.com> References: <4mqp0u$5ok@nadine.teleport.com> I've got 4 little kids and a dog, and if I laid my radials out directly on the surface of the lawn, they would hand me a ball of wire at the end of one weekend. Unfortunately, I have a "multi-use" backyard, and even though Daddy loves his hobby, my kids don't love me much ;) Bill ka9hln Bill Vanstralen KA9HLN St. Paul, MN (612)688-2552 billv21572@aol.com From amsoft@epix.net Sun May 12 18:02:33 1996 From: grhosler@mmm.com (Gary Hosler - KN0Z) Newsgroups: rec.radio.amateur.antenna Subject: Re: Shunt load a tower Date: Wed, 08 May 1996 13:45:19 GMT Message-ID: <4mq8or$pau@dawn.mmm.com> References: <3180288D.1693@p30.s501.c41.k12.wv.us> a_simons@p30.s501.c41.k12.wv.US (Anthony Simons) wrote: >Hello all, Where can I find the best info on shunt loading a tower. I have >a ROHN BX-64 (64' self supporting) with a 3 Ele tri-bander with a dual band >2m/70cm vertical on top. The tower is grounded on all three legs with an 8' >rod with 1/2 copper tubing to each leg. I would like to use the system on >40/80 Meters. Any and all suggestions appreciated. > Thanks & 73, de Anthony KC8BK Sorry to have taken so long to respond to your post but I knew I had an article stashed away on a similiar installation. The August 1990 issue of CQ Magazine had an article (on page 46) by Gary Nichols - KD9SV, and Lynn Gerig - WA9GFR. The article described shunt feeding a 70 foot tower with a TH6-DXX on top. Sounds like a VERY similiar instalation to what your are proposing, and this article also included the 160M Top Band. I plan to shunt feed my 100 foot Rohn 25G (with 15 feet of mast out the top) this Summer in preperation for the Fall/Winter season on Top Band. Good luck on your project. 73 & GUD DX OM de KN0Z Gary in Wyoming, MN Opinions expressed herein are my own and may not represent those of my employe r. From amsoft@epix.net Sun May 12 18:02:34 1996 From: Edward Lawrence Newsgroups: rec.radio.amateur.antenna Subject: Re: The Coax Mentality Date: 6 May 1996 12:55:03 GMT Message-ID: <4mksr7$42c@fcnews.fc.hp.com> References: <4m8ehm$m2a@itnews.sc.intel.com> <4m8usl$5mt@hpcvsnz.cv.hp.com> <4mavg8$g1i@itnews.sc.intel.com> <318A37C1.56FF@haven.ios.com> <4megu5$17o@nnrp1.news.primenet.com> Cecil Moore wrote: >Larry Deering wrote: >: Are you going to use a balun between the coax and the ladder line? > >Hi Larry, does a bear ---- in the woods? :-) Anytime one has >an intersection between balanced and unbalanced RF currents >one should (I want to say must) use a balun of some sort >even if it is a number of turns of coax which is probably >what I will use, honoring the KISS principle. Ten loops >of coax make a reasonable 1:1 HF balun/choke (somebody >correct me if that's not enough turns for 80m). > >50 ohms unbalanced to 50 ohms balanced is usually not a >match unless both ends are floating and my ends are not >floating. :-) If one doesn't use a balun of some sort, >one has feedline radiation - a mortal sin for hams. >----------------------------------------------------------------------------- -- >kg7bk __ __ ____ ___ ___ ____ >kg7bk@primenet.com /__)/__) / / / / /_ /\ / /_ / > / / \ / / / / /__ / \/ /___ / > > Cecil, You obviously have a good background on antenna theory. However I would like to know WHY freedline radiation is a "mortal sin", other than the possibility of RF in the Shack. If I am using a dipole, I obviously don't car e much about directivity. In any event, in the real world other metallic object s in the area will distort the pattern anyway! (Assuming a city lot installation.) So the feed line radiates and gives me an 'extra' vertical component. So what? How is that a 'mortal sin'? This is an honest question, not by any means a flame. Thought I would make that 'perfectly clear". WA5SWD From amsoft@epix.net Sun May 12 18:02:35 1996 From: Edward Lawrence Newsgroups: rec.radio.amateur.antenna Subject: Re: The Coax Mentality Date: 8 May 1996 12:59:24 GMT Message-ID: <4mq5rc$p5f@fcnews.fc.hp.com> References: <4m8ehm$m2a@itnews.sc.intel.com> <4m8usl$5mt@hpcvsnz.cv.hp.com> <4mavg8$g1i@itnews.sc.intel.com> <318A37C1.56FF@haven.ios.com> <4megu5$17o@nnrp1.news.primenet.com> <4mksr7$42c@fcnews.fc.hp.com> <4mped3$7ah@crash.microserve.net> Good answer, Jack! Well phrased, and to the point. Your conclusion seems to be that coax feedline radiation is not necessaraly 'bad', but seldom is good. If you read Cecil's reply to me, you also read that his original statement about it being a 'mortal sin' was a jest aimed at the purists who expound theory without truly understanding what they are talking about. :) I think I like your answer better than any I have heard yet! From amsoft@epix.net Sun May 12 18:02:37 1996 From: tomb@lsid.hp.com (Tom Bruhns) Newsgroups: rec.radio.amateur.antenna Subject: Re: Very small Antennas Date: 8 May 1996 18:29:28 GMT Message-ID: <4mqp68$gep@hpcvsnz.cv.hp.com> References: <31900CAA.3671@ibm.net> Doug Person (ki6bq@ibm.net) wrote: : Now I want to reduce a 40 meter antenna to about 25 ft. That's all the spac e I : have, if I want 40, it must fit in the 25 foot available in the attic. I gu essed : lucky with the 20. How can I calculate the loading coils for the compact 40 ? : I made one using aluminum tubing and fiberglass coil forms hoping to have so mething : I can run my 600 amplifier into. My guess was way off - 16ft #14 on 1.25od form and : about 10 ft of 1" tubing per leg - resonates at 9.745. I can continue to mo dify : deminsions until I get it right - but that is a a lot of attic climbing. An y : suggestions? Yes, my standard reference for just this sort of thing is an old "Ham Radio" magazine article by Joseph Boyer, "The Antenna-Transmission Line Analog." It was in the April and May, 1977, issues. It goes into exactly how to make good engineering-accuracy calculations of loading coils anywhere along the antenna, and gives you a lot of appreciation for how linear antennas work, and why one loading-coil position is better than another. Since you likely will have trouble finding these issues of Ham Radio, I have a standing offer to send photocopies of the article for a SASE and photocopy costs. It's 24 pages, including some relevant pages of one of the references which plots antenna impedance versus length and wire diameter (necessary info to fully use the Boyer article). Send me email if interested. (Design of very short vertical + matching network deleted.) : Here's the bottom line: I have no education in this stuff. I'm just guessi ng at what works. : Does this really do something or am I just tuning a coax longwire? Can I do anything to improve : this concept? Anyone have suggestions, thoughts, ideas, anything at all the y wish to contribute? I'm impressed that it looks like basically a pretty decent design for easy duplication by hams. Things to consider: the feedpoint impedance of a very short antenna is a very small resistance in series with quite a bit of capacitive reactance. That means you need a lot of current to get radiation (from the low resistance), and a high voltage, to get the current through the capacitive reactance. It's hard to make a low loss matching network for that; pay attention to anything that will be lossy. Look up info on optimum coil geometry. Avoid insulations at the high impedance points which might be lossy (hint: Teflon or polystyrene are much, much less lossy than Nylon). Provide _some_ kind of reasonably low loss ground system (several heavy radial wires across the roof?), and make the actual antenna radiator as long as you can (to raise the resistance) and as large diameter as you can (to cut losses from the high current flowing on the surface of the antenna). (Another hint: the matching network, if it's low loss, will be rather high Q, which implies narrow bandwidth. If you are getting much bandwidth, it's a clue that you have a lot of losses besides the radiation from the antenna...) I'd like to encourage you to keep learning. You are making some good early guesses, and with some understanding behind the guesses, you will probably come up with some really neat -- and reasonably efficient -- designs. -- Cheers, Tom tomb@lsid.hp.com From amsoft@epix.net Sun May 12 18:02:38 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Very small Antennas Date: Thu, 09 May 96 09:25:09 GMT Message-ID: <4msdjf$nr@nadine.teleport.com> References: <31900CAA.3671@ibm.net> <4mqp68$gep@hpcvsnz.cv.hp.com> In article <4mqp68$gep@hpcvsnz.cv.hp.com>, tomb@lsid.hp.com (Tom Bruhns) wrote: > [lots of excellent advice]. . . >. . . (hint: Teflon or polystyrene are much, much >less lossy than Nylon). . . I was looking in some references recently for other low-loss materials, and polypropylene looks from the specs to be very good also. And it has a relatively low dielectric constant. One big minus is that it's very susceptible to UV deterioration, so I wouldn't use it outside for an extended period unless you can keep the sunlight off of it. Does anyone have any experience with it as a high-quality insulator or have any information that would confirm or refute the premise that it's good? (This is the stuff you can buy at any discount store as "floating rope".) Roy Lewallen, W7EL From amsoft@epix.net Sun May 12 18:02:40 1996 From: graham@southlin.demon.co.uk (Graham Seale) Newsgroups: rec.radio.amateur.antenna Subject: Re: Very small Antennas Date: Thu, 09 May 1996 20:38:39 GMT Distribution: world Message-ID: <19960509.203839.14@southlin.demon.co.uk> References: <31900CAA.3671@ibm.net> Reply-To: graham@southlin.demon.co.uk In message <31900CAA.3671@ibm.net> Doug Person wrote: > I have made a 20 meter dipole that is 22 ft instead of the usual 33 ft to > fit between two conveniently located trees. This gives me a second antenna > for 20, 90 degrees from the original favoring north/south signals. I used s ome > pvc pipe and about 8 ft of #14 insulated stranded wire close wound to make a > loading coil for each leg - mounted more or less in the legs center. With 1 00 > watts it works great. SWR on the full size 20 is under 2:1 edge to edge. On the > loaded 20 I loose about 100 khz of bandwidth and otherwise find it comparabl e. Hi Doug Before you get too entangled in dissipating the highest current contributions from your antenna in loading coils, try a very simple approach. An antenna shorter than resonance will still deliver radiation energy, but will appear capacitive at the feedpoint. To match a feed to it you need to add inductance to tune out the capacitive component leaving you with something like a unity power factor. This "matcher" is your loading coil. My instinct would be to duck the need for such lossy narrow band things. I would leave the full 33ft of wire in the dipole, but arrange the middle 22ft to be horizontal, and let 5.5 feet dangle down vertically at each end. If this be inconvenient, then fold back the 5.5 foot dangly into a loop back to the support insulator. Do not let the high voltage end connect back to support point. The idea is to force the current to go the distance down the wire the full 33ft. The folded back bit is the beginnings of an *end* loading coil, and will affect the resonant length a bit, but we resist madly making it any more of a loading coil than we absolutely have to. This way, you only mourn the loss of the very little contributions from the ends. If they dangle down, they provide a little vertical component. If you fold them back, the folded part cancels some in the descending part anyway. In practice you will probably find you can fold up the ends of a resonant dipole with very little effect on the tuning, but do it as you would any new dipole - start with a bit extra splaying off the ends, and tune it to resonance by cutting off some inches each side and checking the resonance with a dip meter/noise bridge or somesuch. 73's G4WNT -- Graham Seale From amsoft@epix.net Sun May 19 13:42:55 1996 From: parf@aol.com (Parf) Newsgroups: rec.radio.amateur.antenna Subject: Re: "Patch" Antennas? Date: 11 May 1996 22:09:14 -0400 Message-ID: <4n3h8a$nav@newsbf02.news.aol.com> References: <28011@SP-gw.ampr.org> Reply-To: parf@aol.com (Parf) The antenna you describe sounds more like a bogner. It used disc parasites and a traditional horn exciter w/ a 1/4 W probe. The patch antenna was in QST- December issues have a yearly index. 73, Dale WA2YPY From amsoft@epix.net Sun May 19 13:42:56 1996 From: Shabanov Sergey Newsgroups: rec.radio.amateur.antenna Subject: 2.4 GHz antennas Date: 8 May 1996 12:38:34 GMT Message-ID: <4mq4ka$eeu@news1.demos.su> Help anybody! Where I can buy hi-gain (over 11dB) omni-directional trans-rec. antenna for WaveLAN 2.4 GHz? Sergey Shabanov Rosnet-International From amsoft@epix.net Sun May 19 13:42:57 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: Wed, 08 May 96 16:11:57 GMT Message-ID: <4mql67$j0b@crash.microserve.net> References: <4mq4ka$eeu@news1.demos.su> Post / CC by Mail Shabanov Sergey wrote: >Help anybody! > >Where I can buy hi-gain (over 11dB) omni-directional >trans-rec. antenna for WaveLAN 2.4 GHz? > > >Sergey Shabanov >Rosnet-International Andrew Corporation sells omnidirectional transmit antennas for MMDS (2.5 - 2.7 MHz) and MDS (2.1 MHz) that meet this specification. I'm sure they can provide one tuned for 2.4 GHz. Roughly speaking, these antennas sell for approximately $10,000. Andrew Corp. (U.S. callers): 800-255-1479 73, Jack WB3U From amsoft@epix.net Sun May 19 13:42:58 1996 From: moritz@ipers1.e-technik.uni-stuttgart.de () Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: 10 May 1996 17:50:06 GMT Message-ID: <4mvvke$13rc@info4.rus.uni-stuttgart.de> References: <4mq4ka$eeu@news1.demos.su> <831646102snz@microvst.demon.co.uk> >Maybe antenna theory has advanced beyond me. To show 11dB of gain over >any lossless omni-directional system and remain omni-directional seems >beyond the physics of passive systems. You will have to use amplifiers. Tony, Look how the term "omnidirectional" is defined: it commonly refers only to the azimuth. If you squash the pattern's elevational extention, you have an omnidirectional antenna with gain. Unlike many amateur (mystery) desighns, e.g. minibeams, ground planes without ground plane et.c, they are widely used in commercial applications and work. 73, Moritz DL5UH From amsoft@epix.net Sun May 19 13:42:59 1996 From: blanton@ni.net (J. L. Blanton) Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: Sat, 11 May 1996 11:48:48 -0800 Message-ID: References: <4mq4ka$eeu@news1.demos.su> <831646102snz@microvst.demon.co.uk> <4mtfa8$loh@crash.microserve.net> <831708947snz@microvst.demon.co.uk> In article <831708947snz@microvst.demon.co.uk>, tgold@microvst.demon.co.uk wrote: > Perhaps you live in a two-dimentional world. The array you described > sounds very far from omni-directional to me. For many practical applications the world IS two-dimensional, unless you need to communicate with aircraft or satellites. An omni antenna in azimuth can certainly have gain. Lee, WA8YBT/6 From amsoft@epix.net Sun May 19 13:43:00 1996 From: holstein@erols.com Newsgroups: rec.radio.amateur.antenna Subject: Re: 2m/70cm base station antenna Date: Mon, 13 May 1996 02:22:00 GMT Message-ID: <4n7ckd$3v5@news5.erols.com> References: <318A676F.4724@valmet.com> hannu.forsstrom@valmet.com wrote: >Hi, >I have tried to find an article with information about >building a 70cm/2m base station gp-antenna. What I am >after is an omnidirectional system with a considerable >gain over 1/4lambda gp and that needs only one coax. >Diamond has many different models on market but how to >build one yourself? >Anyone can help me with this? >Hannu/OH6MAZ >hannu.forsstrom@valmet.com Have you thought of using a multiband j-pole. They're very easy to build and you can find the design in recent ARRL handbooks. Check them out at your nearest library. David, N3NGB P.S. I have measured the gain of my two meter j-pole to have 6db gain over a 2m ground plane. From amsoft@epix.net Sun May 19 13:43:01 1996 From: rwa@cs.athabascau.ca (Ross Alexander) Newsgroups: rec.radio.amateur.antenna Subject: Re: 2m/70cm base station antenna Date: 13 May 1996 18:51:14 GMT Message-ID: <4n80b2$shb@aurora.cs.athabascau.ca> References: <318A676F.4724@valmet.com> <4n7ckd$3v5@news5.erols.com> >hannu.forsstrom@valmet.com wrote: >>Hi, >>I have tried to find an article with information about >>building a 70cm/2m base station gp-antenna. What I am >>after is an omnidirectional system with a considerable >>gain over 1/4lambda gp and that needs only one coax. >>Diamond has many different models on market but how to >>build one yourself? >>Anyone can help me with this? >>Hannu/OH6MAZ >>hannu.forsstrom@valmet.com Your requirements are stringent, aren't they? You are asking for dual banded ground plane omnidirectional significant gain (which I choose to mean "+6dBd".) vertical polarization (this is implicit in the reference to Diamond) Discarding the "ground plane" requirement as irrelevant, about the only thing that fits the bill is a pair of colinears sharing a feedline. Get a plan for a 2m colinear, build it, then multiply all the dimensions by 146/435 and build another. Use a duplexer to split the feed if necessary. regards, Ross ve6pdq -- Ross Alexander, ve6pdq -- (403) 675 6311 -- rwa@cs.athabascau.ca From amsoft@epix.net Sun May 19 13:43:03 1996 From: wrap@euronet.nl (eric_augenstein) Newsgroups: rec.radio.amateur.antenna Subject: 3-band scanner antenna Date: 14 May 1996 10:04:25 GMT Message-ID: Hi all, I`m a scanner-freak with no money,for my job (TV-news editor) I need a base antenna like a discone. Does anybody have the measurement`s to build it myself ???? Thanx Jim Wilson scanman@dds.nl From amsoft@epix.net Sun May 19 13:43:03 1996 From: Wayne Shanks Newsgroups: rec.radio.amateur.antenna Subject: Re: 3-band scanner antenna Date: Tue, 14 May 1996 13:44:31 -0400 Message-ID: <3198C67F.504E@wam.umd.edu> References: To: eric_augenstein eric_augenstein wrote: > > Hi all, > I`m a scanner-freak with no money,for my job (TV-news editor) I need a base > antenna like a discone. > Does anybody have the measurement`s to build it myself ???? > Thanx > Jim Wilson > scanman@dds.nl The ARRL antenna handbook hase formulas and data tables for just such a thing. Try the local publick library Wayne S From amsoft@epix.net Sun May 19 13:43:04 1996 From: Lennart Nilsson Newsgroups: rec.radio.amateur.antenna Subject: Re: 80/40/15mtr para dipole Date: 18 May 1996 14:31:35 GMT Message-ID: <4nkn07$bgj@simba.lejonet.se> References: <4n6jar$mvu@news.paonline.com> To: vjkunesjr@fingerlake3.com vjkunesjr@fingerlake3.com wrote: >Has anyone had any experience at building an 80/40/15 mtr parallel dipole (wh ere the 40 meter radiator doubles as a 15 mtr radiator= ). Any advice as to feedlines and >lengths would be appreciated. Thanks. I have used parallell dipoles for 80 and 40 m with the ends of the shorter dipole spaced about 3 meters from the longer one. I had to make the 80 m section longer than calculated and the 40 m section shorter. Resonance frequencies will depend on how much spacing you allow between the dipoles, so it is a cut and try process to tune it. The best feedline is 75 ohms coax or twinlead. On 15 m resonance will be at the high end of the band. You can lower it by adding small wires hanging down from the 40 m antenna wire at the voltage maximum, which should be about 3,5 m from the center insulator. This hardly affects 40 m resonance. 73 de Lennart, SM5DFF. From amsoft@epix.net Sun May 19 13:43:05 1996 From: Ewan Ross McLeod Newsgroups: rec.radio.amateur.antenna Subject: Re: 80mtr loop (cloud warmer) Date: 17 May 1996 10:09:08 GMT Message-ID: <4nhj84$lej@reader1.reader.news.ozemail.net.ozemail.com.au> References: <4ngmqn$1br@news.paonline.com> To: vjkunesjr@fingerlake3.com Yes, plenty experience with antenna type u mention. For regional comms out to 300-400km mount 1/4 wavelength off real gnd. That might be asking too much but closer to ground increases gnd losses but has trade-off of reduced pick-up of manmade noise. We frequently just lay it out across the top of dry grass abt 1mtr off gnd and they perform well. Also more immune to skewing from ionosphere so less fading through cross polarisation than with dipoles. 73s Ewan From amsoft@epix.net Sun May 19 13:43:06 1996 From: Edward Lawrence Newsgroups: rec.radio.amateur.antenna Subject: Aluminiun Foil for Apartment Ground Plane? Date: 17 May 1996 11:24:49 GMT Message-ID: <4nhnm1$n9h@fcnews.fc.hp.com> Ok, This may indeed be a 'wild hair'. Has anyone tried putting Aluminum foil UNDER the carpet in an upper story apartment to act as a local HF ground plane? It looks like I am going to be stuck in apartments for a few years, and I would like to get a decent antenna in an apartment. Can anyone recommend a good book on apartment antennas? WA5SWD From amsoft@epix.net Sun May 19 13:43:07 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Tuner Baluns Date: Wed, 08 May 96 02:20:46 GMT Message-ID: <4mp4fl$3vh@crash.microserve.net> References: <4mm0v0$jka@news.linknet.net> Post / CC by Mail Jonathan Helis wrote: >Currently, I am using an antenna tuner that is a homebrew L-C network >with a single wire input. It was designed for end-fed single wire >antennas. I would like to make a 4:1 balun for this tuner so I can >feed it with twinlead. How to wind a balun is in the ARRL Handbook. >It looks easy, but I can't find anything suitable to wind it on. > >The Amidon catalog has tordoids in it like the diagram in the ARRL >Handbook. Has anyone ever done anything like this? What were your >results? I plan to run not more than 100 watts out of a Kenwood >TS-140S, into a small loop. Hi Jon, First, there are two spreadsheets on my FTP site that might help you design a balun if you have Excel 4.0 for Windows or something compatible. The files are labeled Toroid.xls and Flux2.xls. The FTP site is: ftp.microserve.com/popaccts/h/jackl/ The general rule of thumb when using Toroid.xls is that the the total XL of the winding should be four to five times the impedance of the circuit. Also, for toroids at the FT-240 size, the number of turns should probably be limited to ten or twelve to avoid excessive inter- winding capacitance. Finally, one of the best baluns consists of bifilar turns, wound on the toroid in a manner that creates a current balun. In this configuration, each winding is in series with one conductor of the line. That said, a balun needs to be used in a circuit that presents the input and output impedance the balun is designed for, within reasonable limits. Although the type of system you're planning is widely used, it doesn't meet that qualification. In order to assure balance and maximum transfer of power, you will need to use either A) a balanced tuner like a Match Box instead of the balun, or B) a technique employing variable line length with a tunable (simple) L/C network ahead of the balun. The latter will present the balun with a non-reactive load near its desired load impedance. Cecil Moore (KG7BK) has posted quite a few articles here regarding the latter technique and has written application notes. Those notes are being published by the company that makes the "Ladder Lizard", an inexpensive device for determining SWR, impedance and power on ladder line. The company's name is TechnoLogic Concepts and their e-mail address is: tlcdhconsult@delphi.com You might want to write and see if the notes are available yet. Maybe Cecil will jump in here with more details. ;) 73, Jack WB3U From amsoft@epix.net Sun May 19 13:43:08 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Tuner Baluns Date: 7 May 1996 22:07:02 -0700 Message-ID: <4mpa5m$kj3@nnrp1.news.primenet.com> References: <4mm0v0$jka@news.linknet.net> <4mp4fl$3vh@crash.microserve.net> jackl@pinetree.microserve.com (WB3U) wrote: >You might want to write and see if the notes are available yet. >Maybe Cecil will jump in here with more details. ;) Hi Jack, as far as I know, Don, KE6AJH, has information ready to email and is ready to ship. Just don't believe him when he says the Ladder-Lizard is better than sex. :-) I might explain the final solution (hi hi) here at my QTH. On a transmission line a little bit closer to the transmitter from the current maximum is what I call the PC point, where a single parallel capacitor will cause a Z0 match. If it happens at the transmitter, Z0 = 50 ohms and I call it the PC-50 point. So at the transmitter, I have a 20-200pf variable cap with the ability to switch in other fixed capacitors (thanks Tom). Capacitors are the only reactances that I use to achieve a 1:1 SWR on all frequencies on all HF bands. No lossy coils. How is it possible? If you can't bring the capacitor to a current maximum, then bring the current maximum to the capacitor. Outside my shack window, I have three relays that switch in 32 ft, 16 ft, and 8 ft sections of ladder-line. In the same box with my variable capacitor, I have three switches that will switch in 4 ft, 2 ft, and 1 ft sections of ladder-line. It's easy to see that I can vary my transmission line by 76 to 76+63=139 ft. I always use the shortest possible amount of transmission line to cut down on losses. That's my ultimate (so far) balanced matching system. 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Sun May 19 13:43:09 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Tuner Baluns Date: 11 May 1996 17:56:16 GMT Message-ID: <4n2kc0$jud@news.asu.edu> Cecil said - Of course, I realize this is the old stub-matching approach that my Elmer taught to me 45 years ago. But everything has come together in an easy-to-implement fashion. The only reason that I can think of why this is not the most popular matching system for balanced lines is people don't know about it or don't realize how easy it is to implement. I didn't mean to imply that this was anything new. Cecil, The same can be said about the Series Section Tranformer. some seem to think of only the quarter wave section which only by chance yields a required input impedance for a given termination and small choices of available line Zo. The series section transformer can use often available line Zo to get a wider range of impedances of input and termination. Charlie, W7XC -- From amsoft@epix.net Sun May 19 13:43:10 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna Tuner Baluns Date: 13 May 1996 14:46:01 -0700 Message-ID: <4n8aip$mr1@nnrp1.news.primenet.com> References: <4n2kc0$jud@news.asu.edu> CHARLES J. MICHAELS wrote: : The same can be said about the Series Section Tranformer. : some seem to think of only the quarter wave section which only : by chance yields a required input impedance for a given termination : and small choices of available line Zo. The series section : transformer can use often available line Zo to get a wider range : of impedances of input and termination. Hi Charlie, think about a variable length series section transformer and what one could do with it. ------------------------------------------------------------------------------ - 73, Cecil __ __ ____ ___ ___ ____ kg7bk@primenet.com /__)/__) / / / / /_ /\ / /_ / / / \ / / / / /__ / \/ /___ / ------------------------------------------------------------------------------ - From amsoft@epix.net Sun May 19 13:43:11 1996 From: lutzr@destin.nfds.net (Richard Lutz) Newsgroups: rec.radio.amateur.antenna Subject: AS 1181 UR Millitary antenna Date: 8 May 1996 22:11:26 GMT Message-ID: <4mr66e$e8g@server.cntfl.com> Sure would like to know the specs on this one, looks like: abt 6 in diameter, 4 foot long tube of fiberglass with a stacked set of tuned tubes inside. it checks out well at 146.00 at about 1.6 swr but I wold like to know more. thanks in advance for any e mail or post back here.. 73... KD4SEV lutzr@destin.nfds.net From amsoft@epix.net Sun May 19 13:43:12 1996 From: ad1c@tiac.net (Jim Reisert AD1C) Newsgroups: uk.radio.amateur,rec.radio.amateur.antenna,rec.radio.amateur.misc Subject: Re: Beam Heading Info Date: 11 May 1996 15:30:42 GMT Message-ID: <4n2br2$nv9@news-central.tiac.net> References: <831292354snz@microvst.demon.co.uk> <4mi8fo$l7m@tube.news.pipex.net> <4mn2gt$9hi@infa.central.susx.ac.uk> Reply-To: AD1C@tiac.net (Jim Reisert AD1C) E-mail me your latitude and longitude and I'll send you a printout in return E-mail. 73 - Jim AD1C -- Jim Reisert http://www.tiac.net/users/ad1c/ From amsoft@epix.net Sun May 19 13:43:13 1996 Newsgroups: rec.radio.amateur.antenna From: dgf@netcom.com (David Feldman) Subject: Re: Best Antenna for Apartment ? Message-ID: References: <4mluht$q1i@news.inforamp.net> <3190AA70.97D@arrl.org> Date: Wed, 8 May 1996 15:57:17 GMT In article <3190AA70.97D@arrl.org> Zack Lau writes: >Chris Valliant wrote: >> >> I live in a small apartment, but the landlord won't let me put an >> antenna on the roof. Does anyone know of a good antenna that I can mount >> on the window sill ? I have thought about putting up one without his >> knowledge, but that wouldn't be right. Any idea's would be greatly >> apreciated. Oh yea, this is for the 10 M band (forgot to add that in). > >The 10M band isn't in the best shape for DXing at this part of the >sunspot cycle, though you can work some surprising contacts if you >are patient and don't mind days on end without useful propagation. Try 75! I lived in an apartment in Southern California. _I_ didn't bother telling the landlord... I ran about 120' of fine guage wire out the window to the parking garage across the alley. Ran a KW phone. Lots of fun except when the window sill caught on fire a few times. Never did tell the landlord. All in fun, you see... 73 Dave WB0GAZ dgf@netcom.com From amsoft@epix.net Sun May 19 13:43:14 1996 Distribution: world Newsgroups: rec.radio.amateur.antenna Subject: Re: Big DK3 From: randal.olds@channel1.com (Randal Olds) Message-ID: <40.15254.2422@channel1.com> Date: Thu, 16 May 1996 06:37:00 -0640 EL>Yes. I have on on my Dodge Caravan, but have replaced the 66 inch whip wit h EL>a 102 in whip. Works better. If you have a copy of the construction artic l EL>I EL>would appreciate a copy, as I have mis-placed mine, and others want to buil d EL>one. E-mail me if you have it, and I will send a SASE. Yes I have a copy of the article. I made one of the screwdriver antennas, 2" copper pipe, Mounted on a 1992 ford aerostar van. It didn't work well on 10m or 75m bad swr. I used the (1000pf adj) on 75m and (500pf adj) on 40m. It did put out a nice signal on 20m and 40m, lots of good reports. I'm in the process of making a smaller version to cover 10-40m, out of 1-1/4 and 1-1/2 copper pipe. I also found a place in NY that has a 64-1 gear reduction 12Vdc motor, found it in NUTS & VOLTS mag.. This motor is much smaller than the screwdriver. I just hope it has enough power for the job. KD8NV --- * SLMR 2.1 * ScrewDriver antennas = BIG signal From amsoft@epix.net Sun May 19 13:43:17 1996 From: "William E. Sabin" Newsgroups: rec.radio.amateur.antenna Subject: Re: Coax cable shielding - Help please Date: Sun, 12 May 1996 11:13:25 -0700 Distribution: world Message-ID: <31962A45.68BD@crpl.cedar-rapids.lib.ia.us> References: <831508792.29562.1@tfaloon.demon.co.uk> <19960509.212753.24@southlin.demon.co.uk> <3192A890.16C3@crpl.cedar-rapids.lib.ia.us> William E. Sabin wrote: > > >When the bottom end of the coax (underneath the groundplane) is fed to > >an analyzer the output is in the region of -40 to -60 dBm maximum > >(falling with increasing frequency, and with many notches falling > >into the noise floor). > > The outside of the shield of the coax has an electric field induced > along its length which is "induced" by the antenna. A "boundary > relation" in electromagnetics says that an electric field that is > tangential to the boundary between two regions is the same in both > regions. This means that if the coax is perfect the same electric field > exists on the inside of the shield, inside the dielectric and also on > the center conductor of the coax. If the coax were perfect, the voltage > measured at the analyzer and also at the 50 Ohm termination would be > zero because the two E fields would cancel perfectly. But because of > dielectric and other imperfections the cancellation is not complete. > Even a solid shielded coax would behave the same way, but maybe with > less imperfection. > > Bill Followup from Bill: I set up an experiment to test the explanation that I presented. I will describe the experiment: 1) I used a piece of 50 Ohm coax 3 feet long. 2) The left end has terminal SL (shield left) and CL (center lead left) 3) The right end has terminals SR and CR. 4) Connect a 10 MHz sig gen, hot lead to SL, Gnd lead to SR. This establishes an electric field and a current along the braid of the coax. 5) Connect a 50 Ohm voltmeter between CR and SR. This is the analyzer that was mentioned. 6) Connect a 50 Ohm resistor between CL and SL. This is the top-end termination that was mentioned. 7) Measure the voltage between SR and CR. It was 40 dB below the sig gen voltage. There is almost no current flow in the center lead. 8) Disconnect the 50 Ohm resistor that is between SL and CL. The voltmeter reading now becomes just a few dB less than the sig gen voltage. This voltage is due to capacitive coupling. 9) Re-connect the 50 Ohm resistor between SL and CL. 10) Because the sig gen current flows only on the braid, its H field exists *only* on the outside of the coax and not inside. Therefore the coupling to the center wire is due entirely to the electric field. 11) The electric field on the shield and the electric field on the center lead *cancel* both at the voltmeter and at the termination. 12) This situation is exactly like the direction finder loop. The braid of the coax does not constitute a "shorted turn", therefore it is transparent to the electric field. Bill From amsoft@epix.net Sun May 19 13:43:18 1996 From: "William E. Sabin" Newsgroups: rec.radio.amateur.antenna Subject: Re: Coax cable shielding - Help please Date: Thu, 16 May 1996 18:20:00 -0700 Distribution: world Message-ID: <319BD440.2D1B@crpl.cedar-rapids.lib.ia.us> References: <319660F4.6A7C@crpl.cedar-rapids.lib.ia.us> <832106008.1848.0@tfaloon.demon.co.uk> <31992539.4726@crpl.cedar-rapids.lib.ia.us> <19960515.212023.60@southlin.demon.co.uk> Graham Seale wrote: > > In message <31992539.4726@crpl.cedar-rapids.lib.ia.us> "William E. Sabin" wr ote: > > > I also have a suggestion. If you can find some RF absorption material to > > wrap around the coax, I believe that would be more helpful than anything. > > The additional screen sounds to me like a non-solution. > > Hmm.. Yes, I agree it can help. In my case the only materials allowed in > were expanded polystyrene because the carbon-loaded "Transorb" started to > smoke. > > I still believe the Faraday shield is too effective to be ignored, even if > there are some structures that (confusingly) appear not to be shielded. > > A copper shield (pipe say) with its base set onto the grounded metal wall, > forces a boundary condition. You cannot measure any e-fields within the pipe > more than a couple of diameters from the open end, (unless you get to > frequencies where the hole diameter is a viable aperture). Just because you > put a coax up it is not going to change things. If you let the terminated > end stick out clear into the chamber, you will pick up something. > > As far as I know, this is because no part of the coax is expected to help > the walls of the chamber enforce the boundary condition. Even without a > "outer Faraday shield", a coax does quite well provided you take care to > keep it isolated from the "ground". > > A more serious problem is the severe distorting effect the shield would > have to the field inside the GTEM. In this case, absorber seems to have > clear advantages. > > 73's G4WNT > > -- > Graham Seale Thank you for your comments,Graham, and your ideas are certainly worth tryimg. Bill From amsoft@epix.net Sun May 19 13:43:19 1996 From: Richard Kiefer Newsgroups: rec.radio.amateur.antenna Subject: Re: Coax or 450 ladder line Date: Wed, 08 May 1996 20:16:56 -0700 Message-ID: <319163A8.382A@athena.csdco.com> References: <19960506134557504.AAA74@LOCALNAME> Gary Bishop wrote: > > I plan on building a 1/2 dipole for 12, 17, and 30. Going to have different > wire > > lengths for each of the bands ie: 1/2 wave per band. Is there an advantage in > > using ladder line over coax or vice versa. Thank you. > > Brian Sarkisian KG8CO e-mail: gbishop@tc3net.comHi Brian, I think you should definately use coax. I have found the commonly available ladder line to be VERY lossy with measurments on my HP network analyzer. Much more lossy than good quality coax. I do not know why everyone thinks balanced transmission line is so great. In addition, coax is probably more quiet, or less likely to pick up local magnetic coupled noise from computer monitors, motors, microprocessors in household applicances, etc. You can probably get away without a balun if you bring the coax off the center in a symetrical manner and do not have to much stuff around the antenna. Good luck. Dick Kiefer, K0DK From amsoft@epix.net Sun May 19 13:43:20 1996 From: blanton@ni.net (J. L. Blanton) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.space Subject: Coaxial and/or Counterwound Helix Antennas Date: Wed, 08 May 1996 22:42:30 -0800 Message-ID: I'm thinking about building some circularly polarized antennas for Oscar use (145 & 435 MHz). Has anyone tried installing a 435 MHz helix coaxially inside a 145 MHz helix? Or would there be too much interaction? In a related question, has anyone tried building counterwound helices for the same frequency band on a common framework for left and right circular polarizations (but separately fed, of course)? If anyone can point me to some references in these two areas I'd really appreciate it. Thanks. Lee, WA8YBT/6 From amsoft@epix.net Sun May 19 13:43:21 1996 From: moritz@ipers1.e-technik.uni-stuttgart.de () Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.space Subject: Re: Coaxial and/or Counterwound Helix Antennas Date: 10 May 1996 07:01:14 GMT Message-ID: <4mupjq$1sru@info4.rus.uni-stuttgart.de> References: >In a related question, has anyone tried building counterwound helices for >the same frequency band on a common framework for left and right circular >polarizations (but separately fed, of course)? Lee, For the same amount of material / weight / wind load a cross yagi is better. 73, Moritz DL5UH From amsoft@epix.net Sun May 19 13:43:22 1996 From: Rich Griffiths Newsgroups: rec.radio.amateur.antenna Subject: Re: Code Speed Change: Help Needed Date: Sat, 11 May 1996 12:13:21 -0400 Message-ID: <3194BCA1.7AF6@monmouth.com> References: <4n0ick$1nr2@mule2.mindspring.com> sco@sco-inc.com wrote: > > I propose that the only code speed requirement for Hams in the > U.S. be 5 wpm. I surely don't want to see this happen. And why is this item cluttering the antenna newsgroup? There's already a newsgroup dedicated to policy. Rich W2RG From amsoft@epix.net Sun May 19 13:43:23 1996 From: bowman@montana.com (robert bowman) Newsgroups: rec.radio.amateur.antenna Subject: Re: Code Speed Change: Help Needed Date: 14 May 1996 04:58:25 GMT Message-ID: <4n93th$saf@maw.montana.com> References: <4n0ick$1nr2@mule2.mindspring.com> In article <4n0ick$1nr2@mule2.mindspring.com>, sco@sco-inc.com says: > I propose that the only code speed requirement for Hams in the >U.S. be 5 wpm. Classes of hams could still be distinguished by >different levels of written tests. >Is anyone interested in helping me put together such an effort before >the F.C.C.? Len Winckler, of _Ham Radio and More_ fame, flogged this horse on his program. at last report, he had about 200 responses. either nobody is interested, or nobody listens to his program. From amsoft@epix.net Sun May 19 13:43:23 1996 From: forrest.gehrke@cencore.com (FORREST GEHRKE) Newsgroups: rec.radio.amateur.antenna Subject: Re: Communications Quarterly Message-ID: <8C0A31C.02CF0011C3.uuout@cencore.com> Date: Wed, 15 May 96 13:16:00 -0300 Distribution: world Reply-To: forrest.gehrke@cencore.com (FORREST GEHRKE) References: <4n6bfd$k5a@tribune.concentric.net> JM> I've seen this pub referred to by several people ion the list, would JM> someone please give me an address? I think I want to see about a JM> subscription. Terry Littlefield, Editor Communications Quarterly P.O. Box 465 Barrington, NH 03825 Tell her I sent you! ;-) --k2bt * RM 1.3 02583 * Win'95 fixpak #1:13 disks+new drivers (also known as "os/2") From amsoft@epix.net Sun May 19 13:43:25 1996 From: dnorris@k7no.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Thu, 09 May 1996 00:13:56 GMT Message-ID: <4mrdb5$8ca@news.syspac.com> References: <4mg9ar$l77@crash.microserve.net> <4mlflb$rde@suba01.suba.com> <318FF9EB.211C@erols.com> Jake Brodsky wrote: >byoung@qni.com wrote: >> >> Jack, >> >> I *HAD* a mole problem. I rectified it with several cheap >> battery-powered AM radios. >> >> #1 Tune them to a local rock station with a good signal. >> (needs to be rock-n-roll, moles like classical and country) >> #2 Turn 'em up fairly loud. >> #3 Stick 'em in heavy plastic bags. >> #4 Bury them where you have the problem. >> >> The batteries usually last a week or more, and by then the moles >> have "moved on" to greener pastures. Sounds silly, but it works! >> >> Bill Young >> byoung@qni.com >> KB0UZQ >Where are the smileys? Assuming the small chance that you're serious, >have you tried this? What did your neighbors think? And please tell >us what gave you the notion to try such a silly thing! I wonder if >People for the Ethical Treatment for Animals has anything to say about >this... :-> >Jake Brodsky, AB3A, >"Beware of the massive impossible!" I was fighting gophers (not the Minnesota type) for a long time. PETA found out that I has caused the demise of some small number of these critters and have forced me to pay retribution. This comes in the form of gopher food, scientifically tested for flavor and growth advantage, Now the gophers walk into the house and demand fresh cut veggies and Iced tea (Arizona style). Getting hard to cope..... C. Dean Norris Amateur Radio Station K7NO e-mail to dnorris@k7no.com http://www.syspac.com/~dnorris/ From amsoft@epix.net Sun May 19 13:43:28 1996 From: aor Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Wed, 08 May 1996 12:19:29 -0400 Message-ID: <3190C991.21@gteais.com> References: <4mg9ar$l77@crash.microserve.net> WB3U wrote: > > Lately, I've been thinking about stringing a wire vertical from > a tree and installing a good radial system underneath. However, > there's a wildlife problem that's threatening to thwart my plans. > > During the last two winters, I have been beseiged by an invasion > of moles. The runners they create in the yard and the many mole > hills make it impossible to consider radials. I still have to > cut what's left of the grass, and there's no question that the > moles' activity will push any wires I install up to the surface. > > So far I've tried the following with little or no success: > > Smoke bombs and poison pellets designed for this purpose > Traps designed to kill the mole when it tunnels underneath > Flooding the tunnels with a garden hose > Filling the tunnels with exhaust fumes from my car > 900 VAC at 1 Amp delivered into the ground by aluminum stakes > placed 20 feet apart > Elmer Fudd impressions (lawn chair and shotgun) There has been significant modeling which shows that an elevated radial system of 4-6 wires up can give you the same performance as a 64 burried wire field. On 80 meters, the radials need only be up 15' feet, slightly less for the higher bands. The radials are tuned, (ie 1/4 wave + 5%), and you have have multiple bands. I do not know what your tree-field looks like, but 4-6 elevated radials up 10' or so may fit the bill, and keep the critters at bay!!! 73, Al NW2M From amsoft@epix.net Sun May 19 13:43:30 1996 From: shssci@li.net Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: Thu, 09 May 96 13:05:00 PDT Message-ID: References: <4mg9ar$l77@crash.microserve.net> <4mlflb$rde@suba01.suba.com> In Article<4mlflb$rde@suba01.suba.com>, write: > Path: li.net!news5.ner.bbnplanet.net!news.ner.bbnplanet.net!howland.reston.a ns.net!news.cac.psu.edu!news.math.psu.edu!chi-news.cic.net!news.suba.com!news > From: byoung@qni.com > Newsgroups: rec.radio.amateur.antenna > Subject: Re: Critters > Date: 6 May 1996 18:16:11 GMT > Organization: Suba Communications > Lines: 17 > Message-ID: <4mlflb$rde@suba01.suba.com> > References: <4mg9ar$l77@crash.microserve.net> > NNTP-Posting-Host: 206.29.114.19 > X-Newsreader: SPRY News 3.03 (SPRY, Inc.) > > Jack, > > I *HAD* a mole problem. I rectified it with several cheap > battery-powered AM radios. > > #1 Tune them to a local rock station with a good signal. > (needs to be rock-n-roll, moles like classical and country) > #2 Turn 'em up fairly loud. > #3 Stick 'em in heavy plastic bags. > #4 Bury them where you have the problem. > > The batteries usually last a week or more, and by then the moles > have "moved on" to greener pastures. Sounds silly, but it works! > > Bill Young > byoung@qni.com > KB0UZQ Be careful - I tried this once - it did eliminate the moles, but I found my lawn infested with teenagers... :-) KD2FT From amsoft@epix.net Sun May 19 13:43:31 1996 From: lweissma@motown.ge.com (Larry M. Weissman, X6946) Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Date: 8 May 1996 21:40:43 GMT Distribution: world Message-ID: <4mr4cr$m0o@cnn.motown.lmco.com> References: <318C5813.34A4@ro.com> Reply-To: lweissma@motown.ge.com John D. Farr wrote: > I have a cat that has developed a taste for moles. I have no problems >with them like some of my neighbors. Best of all, my cat brings me the >best parts! >73, John Can I rent your cat for a weekend John? Larry - AD3Y From amsoft@epix.net Sun May 19 13:43:32 1996 From: forrest.gehrke@cencore.com (FORREST GEHRKE) Newsgroups: rec.radio.amateur.antenna Subject: Re: Critters Message-ID: <8C0A321.02CF0011C4.uuout@cencore.com> Date: Wed, 15 May 96 13:21:00 -0300 Distribution: world Reply-To: forrest.gehrke@cencore.com (FORREST GEHRKE) References: <4n6bfd$k5a@tribune.concentric.net> RL> Get yourself an "Out-O-Sight" brand mole trap or clone. It's shaped RL> like a couple of horseshoes spring-loaded together. I've used one RL> for years, and trapped a couple of dozen moles with it. It has never RL> failed to catch a mole. (Occasionally one will trip the trap without RL> being caught but I get 'em eventually.) The Animal Rights people have you in their sights! ;-) --k2bt * RM 1.3 02583 * OS/2: too powerful to be Windows, too easy to be Unix From amsoft@epix.net Sun May 19 13:43:33 1996 From: jafl@msg.ti.com (Jim Flanders) Newsgroups: rec.radio.amateur.antenna Subject: DDRR antenna - reference: RE flagpole antennas Date: 16 May 1996 15:36:13 GMT Message-ID: <4nfi1d$imv@mksrv1.dseg.ti.com> When I answered the article - flagpole antenna - many people emailed me with a question on what is a DDRR antenna. See ARRL Antenna manual page 6-9.DDRR is short for Directional Discontinuity Ring Radiator. First described in Electronics, Jan 1993. Later research described in July 1972 by W2WAM. Imagine the antenna as a small ring insulated just above a ground plane. Distance above the ground plane is 0.0069 wave length. Ring diameter is 0.078 wavelength. The coax feedpoint is 0.25 of distance above ground plane. The far end from the feed is tuned with a capacitor to ground. The diameter of the conductor is large; i.e 40 meters is 2 inches. I recently built one for 40 meters, and it is mounted to look like a car carrier on top of my VAN. I had a muffler shop bend and weld the 2" pipe. It is first mounted on a plywood frame that is covered with copper screen. A motor (from tanner electronics) tunes the capacitor. The whole thing is topped with a fibreglass cover, and the unit is demountable from the van, and can be operated while placed on my outshed. Size of the plywood is 5' X 11'. Jim W0oog/5 in Plano on 147.180 From amsoft@epix.net Sun May 19 13:43:33 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna Subject: Re: Diamond 2m 5/8 mobile antenna (for so239 mount) Date: 10 May 1996 18:42:46 GMT Message-ID: <4n02n6$56e@news.service.uci.edu> References: <3193638B.3CAB@yvv.com> In article <3193638B.3CAB@yvv.com>, sbasile@yvv.com says... >Hi: Does anyone know who manufacturers the Diamond 2m 5/8 mobile whip >with the pl 239 fitting. ... text cut here ... >Thanks, >Sal Sal, Diamond is the manufacturer (or distributor for US market) from Japan. Most Diamond, Comet, and some Anli antennas are made to fit the SO-239 connector mounts. H.R.O. and R.E.S. and most ham radio stores sell these products. If you can not find a store near you, then let me know and I'll give you an address and phone number of several stores when I get home. Brian From amsoft@epix.net Sun May 19 13:43:35 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: Wed, 08 May 96 19:15:16 GMT Message-ID: <4mqrpu$6ov@nadine.teleport.com> References: <95849@gate.kc5aug.ampr.org> <4mg98q$l77@crash.microserve.net> <4mp7ga$3vh@crash.microserve.net> In article <4mp7ga$3vh@crash.microserve.net>, jackl@pinetree.microserve.com (WB3U) wrote: >I'm confused. Two people have mentioned that my reply to the dipole >inquiry was incomplete/incorrect because A) the 2.13 dBi dipole is >only theoretical, and B) the 2.13 dBi dipole is in free space. > >So, I went back and looked at my post. This is what I found: > >>This will create a dipole, although with certain deviations from >>a theoretical model due to practical considerations. > >>the gain will vary with height above ground and soil conditions. > >Was there something about the way I structured my reply that >caused these statements to be overlooked? > >73, >Jack WB3U Your statements weren't overlooked; speaking as one of the posters in question, I just felt that an adequate explanation required more elaboration. A dipole in free space has a gain in its best directions of about 2.15 dBi. If a ground is placed under it, several important (interrelated) things happen. First, the average strength of the entire field increases 3 dB because the energy is now concentrated in a hemisphere rather than being radiated in all directions. Second, energy reflects from the ground and adds to the energy being radiated directly, modifying the pattern and gain. Third, the feedpoint impedance of the antenna changes because of interaction of the field with ground. This in turn changes the strength of the field from the antenna. The net result is a field strength which is several dB greater than that of a free-space dipole (and a very different pattern), for any antenna height over ground of any real conductivity. And, unless you're miles above the Earth, any dipole you construct will be over ground, not in free space. To me, these constitute major differences between a dipole in free space and one over ground, more than "certain deviations. . due to practical considerations" and "[variation] with height above ground and soil conditions". I apologize if I misinterpreted your statements. Roy Lewallen, W7EL From amsoft@epix.net Sun May 19 13:43:35 1996 From: jjo@tekla.fi (Jari Jokiniemi) Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: 09 May 1996 04:38:10 GMT Message-ID: References: <4mmj1n$6kg@news.asu.edu> Well, there is no such thing as a 2.15 dBi dipole in the real world of amateur HF communications due to the ground which we can not get rid off. So what? Let us compare the dipole and a 7 dBd yagi over the real ground at the same height. That yagi does indeed beat the dipole with the great margin of 7 dBd. Who cares how much the gain is in dBi? -- Jari Jokiniemi, jari.jokiniemi@tekla.fi, OH2MPO, OH3BU Tekla Oy, Koronakatu 1, 02210 Espoo, 90-8879 474 From amsoft@epix.net Sun May 19 13:43:36 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: 10 May 1996 05:18:02 GMT Message-ID: <4mujia$lc@news.asu.edu> Jari said - Jari said - That yagi does indeed beat the dipole with the great margin of 7 dBd. Who cares how much the gain is in dBi? Jari, If it is understood that you are only comaring the gain at the peak of the lobe then there is no problem. But when you start to compare other pattrts/// parts of the pattern, it is not always clear whether you are comparing those parts with the dipole pattern parts at the same coordinates or if you are referenceing it to the peak of the dipole lobe. Charlie, W7 XC -- From amsoft@epix.net Sun May 19 13:43:37 1996 From: "John D. Farr" Newsgroups: rec.radio.amateur.antenna Subject: Re: dipole vs dipole gain Date: Wed, 08 May 1996 01:24:39 -0500 Message-ID: <31903E27.693A@ro.com> References: <95849@gate.kc5aug.ampr.org> <4mg98q$l77@crash.microserve.net> <318D9976.3D77@erols.com> <4mklk6$qgh@nadine.teleport.com> Roy Lewallen wrote: > > In article <318D9976.3D77@erols.com>, > Jake Brodsky wrote: > >Jack, I think you're missing something here. The dipole he's referring > >to is the THEORETICAL dipole. It is a mathematic model with wires that > >have zero resistance, negligible size, it assumes a center, balanced > >feed, and each half is 1/4 wave. Yes, this *theoretical* dipole will > >have the 2.13 dB gain compared to an isotropic radiator. I remember > >computing the antenna patterns of such a dipole in my EE studies at > >the Johns Hopkins University's Electricity and Magnetism class. It's > >been over six or seven years since I did it and the math wasn't exactly > >pleasant. I don't think I could (or should) repeat it here. > > > >Jake Brodsky, AB3A, > >"Beware of the massive impossible!" > > There's one more thing about the 2.15 dBi dipole. It's in free space. This > makes it as much a fictitious antenna as an isotropic radiator. Even a very > high real dipole won't have a pattern or gain remotely resembling that of > the theoretical free space dipole -- the gain of the real dipole will > typically be several dB greater. It's no trick at all to put a dipole in > your back yard which has 4-5 dBd gain, where dBd is dB relative to a > free-space dipole (0 dBd = 2.15 dBi). > > Roy Lewallen, W7EL Indeed, indeed. You also need to look at the direction of the main lobe. You might get 4-5 dBd gain, but if the main lobe is straight up, it don't do much good! Antenna height is critical. John KC4ZXX From amsoft@epix.net Sun May 19 13:43:38 1996 From: Darrell Barabash Newsgroups: rec.radio.amateur.antenna Subject: Re: Familiar with this antenna book? Date: Sat, 11 May 1996 23:29:12 -0500 Message-ID: <31956918.2E88@iamerica.net> References: <4msfs7$4e4@news.dx.net> KC8CGX wrote: > Anyone familiar with this book: "Antenna Engineering > Handbook, Second Edition", Ed by R.C. Johnson & H. Jasik, > pub by McGraw-Hill. This is a very good, practical book that covers many types of antenna systems. It gets into the theory but not too deep. You can get it for $12.95? Don't even give that a second thought -- get it. At full retail it's more than worth it. From amsoft@epix.net Sun May 19 13:43:39 1996 From: mbrinkho@falcon.inetnebr.com (Matt C. Brinkhoff) Newsgroups: rec.radio.amateur.antenna Subject: Feed 10M & 2M antennas with one feedline? Date: 14 May 1996 00:12:08 GMT Message-ID: <4n8j4o$aqi@duck.inetnebr.com> I would like to know if anyone has used a single feedline for two antennas. I am wondering if I can feed my 10M dipole and 2M turnstyle with the same coax and use a duplexor at the rig for satellite work. If it is possible, does it matter which antenna is closer to the rig? What impact does the distance between the two antennas have? Would it be possible to feed three antennas in this fashion? (10M/2M/430)? Thanks. -- Matt C. Brinkhoff, KB0RXC mbrinkho@inetnebr.com http://incolor.inetnebr.com/mbrinkho Lincoln, Nebraska [EN10] From amsoft@epix.net Sun May 19 13:43:40 1996 From: Jack McClain Newsgroups: rec.radio.amateur.antenna Subject: Re: Field Day wire antenna hints needed Date: Tue, 07 May 1996 07:44:43 -0400 Message-ID: <318F37AB.CCE@radio.org> References: <3184ABA0.41C67EA6@plhp002.comm.mot.com> <3186C786.7415@radio.org> <4mlgmf$fdm@huron.eel.ufl.edu> John Hughes wrote: > > > For a number of years our Field Day stations consisted of erecting > > tri-band beams on portable 75 foot towers for the high bands and various > > dipoles or double extended Zepps for 40 and 80 Meters...even tried a > > G5RV one year! > > > > BUT - the last three years we've abandoned those antennas in favor of > > Horizonal loops. (I should have started with the fact that we operate in > > class 2B - One SSB station and one CW station) > > > > It's so simple if you have any sort of supports to put up as big a loop > > as you have room for and as high as you can get it. Works well even at > > 25 feet. We feed ours with 450 ohm ladder line and use a tuner > > (Transmatch) to match the transceiver. This antenna works well on all > > bands, so well we don't even miss the beam for 10-15-20. > > > > 73, Jack ae4q@radio.org > > Loops/ladderline sound gud, but tell us where did you all get the 75ft > portable towers???? > > 73 Surplus trailer-mounted fold-over 75' towers! Originally used for microwave site selection tests for microwave routes. Fiber Optics technology had made the towers surplus! 73, de AE4Q From amsoft@epix.net Sun May 19 13:43:41 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna Subject: Re: Field Day wire antenna hints needed Date: 10 May 1996 18:31:38 GMT Message-ID: <4n022a$56e@news.service.uci.edu> References: <4mlgmf$fdm@huron.eel.ufl.edu> <4mlu8q$mk3@news1.t1.usa.pipeline.com> <31924A46.1E6A@cellnet.com> In article <31924A46.1E6A@cellnet.com>, jdd@cellnet.com says... >Not exactly in My ham budget! >Cheers. >Jim, WU0I >ke6ber@usa.pipeline.com wrote: >> In article <4mlgmf$fdm@huron.eel.ufl.edu>, John Hughes writes: >> >Loops/ladderline sound gud, but tell us where did you all get the 75ft >> >portable towers???? >> >73 I have a friend with a military style guyed crank up that's about 50ft. I'd buy it myself but really can't justify it to my wife. If you or a club is interested, the cost is almost 1/10 the 75ft unit mentioned earlier. Brian From amsoft@epix.net Sun May 19 13:43:42 1996 From: Lan Administrator Newsgroups: rec.radio.amateur.antenna Subject: Flag Pole Antenna Date: 14 May 1996 15:08:05 GMT Message-ID: <4na7km$shd@atlantis.utmb.edu> Greetings all. I am getting ready to relocate to another town and I am afraid that the covenants in the neighborhoods are not accomodating to towers. I have been researching different types of "stealth" antennas and have decided that a flag pole antenna would be the most asthetically (sp?) pleasing, and for the neighborhood watch dogs to deny it would be unpatriotic. My questions are: are there any readers that have experience with these types of antennas? Or do you have any other ideas? I have looked at Isoloops, dipoles attached to the facia, attic wires, ..... I have a good idea how to make a concealed groundplane for the flag pole (the XYL loves gardening), so that is not a problem. please email responses to bdoreck@beach.utmb.edu TIA de KC5GWA Bren Doreck tryin' to get over the 10wpm hump From amsoft@epix.net Sun May 19 13:43:43 1996 Newsgroups: rec.radio.amateur.antenna From: Marilyn Swartz Subject: FM Antenna Question Message-ID: <318F1AD9.622A@sfusd.sf.ca.us> Date: Tue, 07 May 1996 02:41:45 -0700 Sorry that this isn't a question about esoteric antenna theory, but here goes: I recently bought an R-95 Yamaha receiver to listen to FM stations. I am using the simple wire-loop antenna that came with the receiver. However, as I live very close to a radio tower (Sutro tower in San Francisco), it is very difficult to get certain stations because of the interferance--they come in, but with a lot of static and only after moving the antenna around a lot. Would getting a better antenna help, and if so, which one? The people at Good Guys, where I bought the receiver, only reccommend the Terk brand antennas they have availiable. I would prefer to use an indoor antenna if possible, however--but it seems that my problem is mainly antenna selectivity, not sensitivity, so I doubt a large antenna would do anything. Thank you very much in advance for your help. From amsoft@epix.net Sun May 19 13:43:44 1996 From: Dave <73073.46@CompuServe.COM> Newsgroups: rec.antiques.radio+phono,rec.radio.amateur.antenna,rec.radio.amateur.homebrew,rec.radio.shortwave,rec.radio.swap Subject: For Sale- Rider Manuals & SAMS Date: 18 May 1996 13:57:17 GMT Message-ID: <4nkkvt$fqt$1@mhadf.production.compuserve.com> Hello Friends, I have several Rider Perpetual troubleshooting manuals for Radio and Televisions for sale. I also have a nearly complete set of SAMS Photofact of the month series until the year 1991. This from my Father's business which I closed a few years ago. The overall condition of the Rider manuals are good, as well as most of the sams folders. If you have any interest in all or part of these sets, please respond by E-Mail to DSkalish@aol.com , OR 73073.46@compuserve.com Thanks for your time Dave Skalish From amsoft@epix.net Sun May 19 13:43:44 1996 From: dave@curly.virtual.org (David Black) Newsgroups: rec.radio.amateur.antenna Subject: Foxhunt antenna? Date: 16 May 1996 16:48:19 GMT Message-ID: <4nfm8j$7nh@moe.virtual.org> I'm looking for information on how to build foxhunt/T-hunt handheld antennas for 2m, 440 and 1.2. We have some creative people here in the Bay Area who've sent along some idears, and I'm told there is a book by the ARRL available too. I'd like to build something that's small enough to use while driving around in a car, while attached to an HT. Cheers, Dave KE6AJC From amsoft@epix.net Sun May 19 13:43:46 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.equipment Subject: Re: Glass mount on "shaded" window Date: 13 May 1996 20:51:15 GMT Message-ID: <4n87c3$hhv@news.service.uci.edu> References: <31974F69.5048@tor.comm.mot.com> In article <31974F69.5048@tor.comm.mot.com>, louisb@tor.comm.mot.com says... >Hello all, >Does anybody have any experience with the "patterned" sun shade at the >top of the rear window of >GM cars (mine is a 92 Chev Corsica)? >Thanks > --Louis I was told by the manufacturer of the antenna (Larsen) to avoid the patterned area. I used the area where the heater wires are about two inches below the bottom of the pattern and stratled the heater wires with the antenna coil plate horizontal (parallel to the wires). I did this on my Chevy Lumina which I believe is the same style glass as the Corsica and it performed well. After about 1-1/2 years, the glue started to seperate on the outside antenna, so I reglued it using contact cement and it was fine until I returned the vehicle (company car). Be careful to check the mounting regularly and DON'T exceed the power capability. Brian - N6ZAU From amsoft@epix.net Sun May 19 13:43:47 1996 From: jmhilliard@aol.com (JMhilliard) Newsgroups: rec.radio.amateur.antenna Subject: Re: Help - Offshore vessel has antenna proble Date: 17 May 1996 10:41:22 -0400 Message-ID: <4ni36i$eel@newsbf02.news.aol.com> References: <3199EBD3.697@ix.netcom.com> Reply-To: jmhilliard@aol.com (JMhilliard) Bill, do you have a chart of the HF SSB channels/frequencies? I would like to listen, but cannot find a chart anywhere! Mark Hilliard, N2HHR Formally: mark@kodak.com JMhilliard@aol.com From amsoft@epix.net Sun May 19 13:43:48 1996 From: bprender@lynx.dac.neu.edu (Brian Prendergast) Newsgroups: rec.radio.amateur.antenna Subject: Help needed Date: Tue, 14 May 1996 12:19:14 -0500 Message-ID: Here the situation, I'm just starting in on this radio thing and I'm having a problem figuring out what is best. I started with a couple of 49 MHZ radio shat in pocket communicators so I could play paintball and talk to another member of my team at the same time. I quickly found out that the refs use the same frequency and that the rang and clearity wasn't that good. I nneded something that would work better since I didn't have time to play around with things while I was playing paintball. I also tryed to use these in the car since we travel in multiple cars a lot and I thought it would be nice to be able to talk to each other. At any rate this didn't work. I returned them and figured I would give a CB a shot. It started out really good, then I realized that the CB (a hand held one) would be great for paintball, but not very good for the car since it picked up every little electronic devise in my car, since I have a stereo well over $1000 and an alarm to guard it along with a radar detector to watch for police oh and I can't forget about the pager and cell phone. Anyway you get the point, I'm into electronics. So now I hear all about these HAM radios, and VHF. How far can they reach and what kinds are the best, how much do they cost, where can I get them, are there a lot of people using them? You get the idea, I have no clue about them. I know I need a licencse and that's about it. Some one has been a great help to me so far, any more help would be greatly appreciated. I am extreamly interested in what the benefits are off having the VHF as opposed to the CB. Well please get back to me, one of the more important things is cost and range. I want to creat a docking station for it for my home and for my pickup truck. I am very interested on how far people think they can go. Please email me at bprender@lynx.dac.neu.edu with any help. I don't read these all the time so I would probibly miss any resonse to this. Thanks for any help at all...... From amsoft@epix.net Sun May 19 13:43:49 1996 From: pcb@connix.com (pete brunelli) Newsgroups: rec.radio.amateur.antenna Subject: Re: HF Mobile Magnetic Mount Date: Fri, 17 May 1996 13:06:07 GMT Message-ID: <4nhtn0$i97@comet.connix.com> References: <199602251723.MAA11927@soho.ios.com> rlc@soho.ios.COM wrote: >Can anyone give me feedback on using any type of HF antenna with the >extra large multi-pad magnetic mounts? Bob AA2UV >(rlc@soho.ios.com) I have had varied results, though typically bad. One problem will be getting a decent connection to ground. The magmount alone is a poor approximation of a ground connection. A hardpoint connection to the chassis would help alot. Even if it "tunes" ok, the efficiency will be extra-miserable. The big H pattern mounts are a big improvement, especially at hwy speeds. I have had my outbacker blow off at about 60mph and it was pretty hair-raising. GL From amsoft@epix.net Sun May 19 13:43:50 1996 From: F. Kevin Feeney Newsgroups: rec.radio.amateur.antenna Subject: Re: HF Mobile Magnetic Mount Date: 17 May 1996 15:24:10 GMT Distribution: world Message-ID: <4ni5mq$pat@newsstand.cit.cornell.edu> References: <4nhtn0$i97@comet.connix.com> In article <4nhtn0$i97@comet.connix.com> pete brunelli, pcb@connix.com writes: >rlc@soho.ios.COM wrote: > >>Can anyone give me feedback on using any type of HF antenna with the >>extra large multi-pad magnetic mounts? Bob AA2UV >>(rlc@soho.ios.com) > >I have had varied results, though typically bad. One problem will be >getting a decent connection to ground. The magmount alone is a poor >approximation of a ground connection. A hardpoint connection to the >chassis would help alot. Even if it "tunes" ok, the efficiency will >be extra-miserable. > >The big H pattern mounts are a big improvement, especially at hwy >speeds. I have had my outbacker blow off at about 60mph and it was >pretty hair-raising. > >GL > > All the ones I've looked at, even the H mount types, don't have much of a connection to ground - and you need that for the antenna to perform well. I finally built my own. I started with a 14 inch square aluminum plate laid flat on the roof to get enough capacitance to ground. Bigger would be better - I scaled it up from the amount of area typical for a 10/11 meter whip, and then doubled that. The plate is countersunk on the bottom for screws that go up into two wood rails that run over the top to magnets on the outsides of the plate. I use some washers to take up the gap from the top of the magnets (bottom of the rails) to the plate so it's pushed down firmly on the roof. I put a bud box in the middle of it, a little forward of center, and mounted an RS ball mount on that. Inside the box is a switch to switch in various caps at the base for matching on the lower bands. The coax is routed out the rear of the box and down into the car via a doorsill. I use hamsticks on it (on top of a dodge caravan) and get good reports on 40 meters on up, often complimented on the strength of the signal. I attribute that mostly to a better than average ground connection for the antenna compared to the other mag mounts they hear. My 2:1 bandwidth is narrower than others see, also an indication that my ground losses are probably lower. It's been in service for about 5 years on and off now. I have to replace the RS ball every now and then, and the switch needs to be redone also. It's only been knocked off the roof once, and that was a low tree limb at 45 mph that hit the fiberglass part of the whip and really did a job on things. Cracked the RS ball base along with damage to the hamstick. But on more normal encounters, I just hear a big "Boing!" typically. I routinely drive through the local 'McBarnyards Golden Starches' which just clears the fiberglass portion of the hamstick and folds the whip right back - and it's never come unstuck. It's never come unstuck due to wind. Total cost was probably about $30, get some big magnets with cups that you can screw to at a hamfest, use 1x2's for the rails, and I think I got the bud box at RS although there are probably sturdier ones. I mounted the box with the U shaped section screwed to the plate, and then stood the outer U, with the flanges along the sides that help stiffen it, on top of it, replacing the original screws with brass ones after they rotted out. The best thing would be to get a direct low Z connection to ground, but that isn't always an option. This was my answer to it. Your milage may vary. On a side note, when there's no antenna on the ball, it's amazing how many people thinks it's some kind of 5th wheel trailer hitch. Coming home from a hamfest once when it was on my VW Rabbit, I was hysterical as someone joined our group on simplex and asked about the '5th wheel hitch on the roof of the rabbit. ' Some of my travelling companions had him convinced that I towed a 25 foot rig with the thing, and still got 32 MPG. I think next they were going to sell him some beachfront property on mars! 73 de Kevin, WB2EMS "When I was a child, mommy told me not to talk to strangers. Now that I'm a ham, it's my hobby!" From amsoft@epix.net Sun May 19 13:43:51 1996 From: Garth Wiscombe Newsgroups: rec.radio.amateur.antenna Subject: Re: HF Vertical Date: 9 May 1996 02:03:21 GMT Distribution: world Message-ID: <4mrjp9$atm@NEWSnewsNeWsnEwS> References: <318E30B4.49E4@aa6g.org> <4mlu3m$mfn@news1.t1.usa.pipeline.com> To: ke6ber@usa.pipeline.com ke6ber@usa.pipeline.com wrote: >In article <318E30B4.49E4@aa6g.org>, Chuck Vaughn writes: > >>George J. Molnar wrote: >>> >>> Dan Tang wrote: >>> > >>> > Can some one please tell me if an hf vertical antenna install on the >roof >>> > (with radials) works as good as it install on the ground (with >radials)? >>> >>> It'll probably work a bit better, presuming you install a good-quality >>> set of radials on the roof. >> >>And not only that, but you can get the impedance closer to 50 ohms >>by sloping the radials down. >> >>Chuck - AA6G > >I used to have a Cushcraft AP8A mounted on my chiney. I had VERY good luck >with it. Good performance for both domestic and DX contacts. Really >enjoyed it. Good luck. >Al, KE6BER/1, KE6BER@usa.pipeline.com > Just a note: You may want to check with the manufature of your particular vertical to see if the radials are longer with the roof top mount than the ground mounting. For example I have the AV5 and the radials for the 80 meter band are 6 feet longer for the roof mount than ground. My installation instructions came with the information for both ground and roof mounting. The comment of coming closer to 50 ohms because of angle are also very true and are discussed in brief in the installation instructions that I have for my antenna. Have Fun. -- ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ * * * * * Garth Wiscombe, KA7MHN /\ /\ * * / / / Office 801 265-5057 Salt Lake City / \/ \ /\ ----/\--- Cellular 801 631-8675 Utah 84119-6032 /\ \ \ \ / / || / Home 801 967-3236 USA / \ \ \ \ || FAX 801 967-3268 / \ \ \ \ || E-mail garth@alinc.com 73 de Garth KA7MHN ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ From amsoft@epix.net Sun May 19 13:43:52 1996 From: Siegfried Rambaum Newsgroups: rec.radio.amateur.antenna Subject: Re: High SWR Help Date: Fri, 10 May 1996 14:52:42 -0400 Message-ID: References: <000006850000303E@nashville.com> On 8 May 1996, Steve Lee wrote: > Here's what he's doing. He has a Cobra 148F and a Firestik 2 antenna. Humm ... this sounds, as if your friend only installed half the antenna. The other half of that antenna would be the car; the Firestick and the car give a complete antenna system (i.e. form a groundplane) .... I guess, he would need to add radials like it is the rule for each decent groundplane. > He can't have an outdoor antenna where he is at. So, he mounted the > antenna in his attic. The antenna is 3 feet tall just below his roof > inside the attic. He's using 50 feet of RG58 coax , new from Radio > Shack. This is a mobile style antenna, but he is using his radio as a base ******************** here you say it yourself... From amsoft@epix.net Sun May 19 13:43:53 1996 Newsgroups: rec.radio.amateur.antenna From: n4lq@iglou.com (Steve Ellington) Subject: Re: Horizontal HF loops Message-ID: References: <317CF945.31D2@ldp.com> <4lteku$6aq@consolidated.ccinet.net> <4mfqhj$ijd@everest.vol.it> <4mjua9$n3f@nnrp1.news.primenet.com> <31959790.3AA5@mbox.vol.it> Date: Mon, 13 May 1996 20:39:08 GMT I have tried using things like eyebolts and insulators but even the softest wire won't pull through them with a lot of effort. The pully idea sounds great as long as they swivel and the wire doesn't jump off and jam beside the pulley. -- Steve Ellington N4LQ@IGLOU.COM Louisville, Ky From amsoft@epix.net Sun May 19 13:43:56 1996 From: P Tyers Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew Subject: Re: HOW DO U CONNECT COAX TO QUAD???????? Date: Fri, 10 May 1996 14:08:58 +1100 Message-ID: <3192B34A.6EF1@trl.oz.au> References: <318c1477.108916@news.atl.mindspring.com> Monty Wilson wrote: > > billp8@atl.mindspring.com (Bill Poston) wrote: > >I am attempting to homebrew a quad antenna. I have read Cubical Quad > >Antennas by W6SAI and the ARRL Antenna Book. Neither answers my question. > > > >How do I connect one coax feedline to the multiple loops on the driven > >element? > > > >Please explain in detail so that a dummy can understand. > Have another read of Cubical Quads. What you actually end up doing is producing a multiple gamma match, one for each loop. Of course they interact to all heck while being adjusted.I seem to recall that the preferred order of adjustment was from smallest loop to largest loop for minimum interaction - BUT I COULD BE TOTALLY WRONG ON THIS. Another source of information is a series of articles published in the Wireless Institute of Australia magazine "Amateur Radio" about 15 +/- 5 years ago on multiband quads which had several column inches on the care and feeding of these gamma matches. Hope this helps! -- P Tyers, Tel. +61-(0)3-92536794 AARnet: p.tyers@trl.telstra.com.au CSnet: p.tyers@trl.oz.au HAM: VK3KTS MAIL: Telstra Research Laboratories,P.O. Box 249, Clayton,VICTORIA 3168,AUSTRALIA From amsoft@epix.net Sun May 19 13:43:57 1996 From: mluther@tamu.edu Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew Subject: Re: HOW DO U CONNECT COAX TO QUAD???????? Date: 11 May 1996 05:45:45 GMT Message-ID: <4n19i9$ie4@news.tamu.edu> References: <318c1477.108916@news.atl.mindspring.com> <3192B34A.6EF1@trl.oz.au> Reply-To: mluther@tamu.edu In <3192B34A.6EF1@trl.oz.au>, P Tyers writes: >Monty Wilson wrote: >> >> billp8@atl.mindspring.com (Bill Poston) wrote: >> >I am attempting to homebrew a quad antenna. I have read Cubical Quad >> >Antennas by W6SAI and the ARRL Antenna Book. Neither answers my question. >> > >> >How do I connect one coax feedline to the multiple loops on the driven >> >element? >> > >> >Please explain in detail so that a dummy can understand. >> > >Have another read of Cubical Quads. What you actually end up >doing is producing a multiple gamma match, one for each loop. >Of course they interact to all heck while being adjusted.I >seem to recall that the preferred order of adjustment was >from smallest loop to largest loop for minimum interaction - >BUT I COULD BE TOTALLY WRONG ON THIS. > > Another source of information is a series of articles >published in the Wireless Institute of Australia magazine >"Amateur Radio" about 15 +/- 5 years ago on multiband quads >which had several column inches on the care and feeding of >these gamma matches. > >Hope this helps! > >-- >P Tyers, Tel. +61-(0)3-92536794 >AARnet: p.tyers@trl.telstra.com.au >CSnet: p.tyers@trl.oz.au HAM: VK3KTS >MAIL: Telstra Research Laboratories,P.O. Box 249, > Clayton,VICTORIA 3168,AUSTRALIA You're right on target! Highest to lowest frequency. It takes some juggling. However, once done, the match stays done. I've used the gamma match feed system on quads (and virtually everything else I can reasonably adapt it to. It works on the quads VERY well. Another tip. In stead of chasing all over heck and back for big variable capacitors as you get down to 40 and 80 meter quads, use a chunk of RG-8 coax cable as a capacitor. It has capacity and a nice hefty dialectric that will let you use the inner conductor as one arm of a capacitor and the outer shield as the other arm. You get it too long by a foot or so for the total capacity you need. You whackem off an inch or so at a time at lower power to trim away the capacitance. You use a much smaller air variable for the trimmer. When done, presto, BIG heavy cap for 40 and 80 meter versions heap cheapo. Be sure to trim away some of the braid and leave an inch or so of the inner conductor and insulation extended to avoice arcing at high power.... Tape the end up to excude water. Smile all the way to the bank. :) Mike W5WQN as a guest at leviathan.tamu.edu (No mail address there) From amsoft@epix.net Sun May 19 13:43:58 1996 Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew From: "Al Koblinski (W7XA)" Subject: Re: HOW DO U CONNECT COAX TO QUAD???????? Message-ID: To: billp8@atl.mindspring.com References: <318c1477.108916@news.atl.mindspring.com> Date: Thu, 9 May 1996 23:56:14 GMT I use a 1:1 balun for each loop (Bencher, but any brand is OK). Where needed I used a coax matching section to match. On 20mtr, my 3 el on 26' boom was 49 ohms so no matching was needed for 50 ohm coax. Ditto for 5 el on 15 mtrs with same boom. 10 meters, 5 elements came out to near 90 ohms impedence and I used a section of 75 ohm coax between the balun and the 50 ohm feedline. Each element is fed seperately through a switchbox. I have used a variety of other feed methods in the past, such as gamma matching (cumbersome) and found that the simple balun approach works great and is mechanically the most simple. 73, Al From amsoft@epix.net Sun May 19 13:43:59 1996 From: dvoges@mail.global.co.za (David Voges) Newsgroups: rec.radio.amateur.antenna Subject: Info required for Telescoping mast Date: Mon, 13 May 1996 17:02:19 GMT Message-ID: <4n70t7$3ll@dodo.global.co.za> Reply-To: dvoges@mail.global.co.za Hi I have a telescopic mast (pump-up type) which has the name CLARKE engraved on it. Can someone tell me where I can find information on this mast ?. I need to service it and and also replace all the O-rings. From amsoft@epix.net Sun May 19 13:44:00 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: ISOTRON Antenna Information Date: 8 May 1996 14:15:21 GMT Message-ID: <4mqa9p$c2@itnews.sc.intel.com> References: <4mogau$mh9@clark.zippo.com> blazar@ea.net wrote: >Any information will be greatly apreciated. TIA. Hi Barry, IMO you would be a lot better off running $10 worth of wire in your attic. Have you seen any radiation efficiency specs on the Isotrons? 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Sun May 19 13:44:01 1996 From: blazar@ea.net (Barry LaZar) Newsgroups: rec.radio.amateur.antenna Subject: Re: ISOTRON Antenna Information Date: Thu, 9 May 1996 06:34:43 +1000 Message-ID: References: <4mogau$mh9@clark.zippo.com> <4mqa9p$c2@itnews.sc.intel.com> In article <4mqa9p$c2@itnews.sc.intel.com> Cecil Moore writes: >From: Cecil Moore >Subject: Re: ISOTRON Antenna Information >Date: 8 May 1996 14:15:21 GMT >blazar@ea.net wrote: >>Any information will be greatly apreciated. TIA. >Hi Barry, IMO you would be a lot better off running $10 worth of >wire in your attic. Have you seen any radiation efficiency specs >on the Isotrons? >73, Cecil, KG7BK, OOTC (not speaking for my employer) > Cecil, Thanks for the response. All I know about the antenna(s) is what I have read in a couple of 73 articles. 73 /Barry, K3NDM From amsoft@epix.net Sun May 19 13:44:02 1996 From: raiar@inlink.com (Gary V. Deutschmann, Sr.) Newsgroups: rec.radio.amateur.antenna Subject: Re: J-pole vs. half wave dipole. Date: Thu, 16 May 1996 21:55:40 GMT Message-ID: <4ng8j6$9m4@news2.inlink.com> References: <4mnq2r$1dq@news.indy.net> <4mnu2v$1gg6@info4.rus.uni-stuttgart.de> moritz@ipers1.e-technik.uni-stuttgart.de () wrote: >>Thinking of putting up simple vertical for 6M. The J-pole was initial choice >>but then I wondered if the 1/4 wave, non-radiating, matching section was >>really worth the trouble. How much better is the J-pole than a simple 1/2 wa ve >>dipole fed with 75 ohm coax and a ferrite decoupler on the outside of the co ax >> at the feed point? >Hi John, >The J-pole better? definitely not. First the 1/4 wave section radiates to >some extent, because one side is loaded by tha antenna and it is not >strictly symmetrical, and this degrades antenna gain. Second in a J-pole the >impdeance is transformed to very high values at the feed point, which in >most cases will introduce extra losses. Third, you need to worry about >a symmetric feed with both antennas, else the feed line radiates. >The J-pole is am electrically poor design, but it has its followers. >Fortunately it is our privilege to be irrational. >73, Moritz DL5UH Not everyone has room for a counterpoise! TTUL Gary From amsoft@epix.net Sun May 19 13:44:03 1996 From: jgozzo@mitre.org (James S. Gozzo) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.equipment Subject: Re: Larsen glass mount antennas Date: Thu, 16 May 1996 08:17:51 -0500 Message-ID: References: <5e7cc$11271c.2ce@NEWS> I've had a Larsen 2m glass mount since 1989. The antenna works fine and the adhesive has been great. When I got a new car I removed the antenna (much work with acetone, a putty knive and lots of elbow grease) and wrote to Larsen about how to re-install the antenna. They sent me a re-installation kit gratis - contained the glass cleaner, the double-sided adhesive and isntructions. Follow the instructions and make sure the mounting surface is clean and dry. I've never had a problem with the adhesive coming loose. 73, es cul Jim, WG1Y p.s. I have no connection with Larsen. They just seem to be a good company. -- Jim Gozzo jgozzo@mitre.org From amsoft@epix.net Sun May 19 13:44:04 1996 From: EJVJ40A@prodigy.com (George Deamicis) Newsgroups: rec.radio.amateur.antenna Subject: Long Wire Date: 18 May 1996 17:14:10 GMT Distribution: world Message-ID: <4nl0h2$1bja@usenetp1.news.prodigy.com> I have the oppittunity to run two long wires about thiry feet up. One would be approx 175 to 200 feet the other about 120 feet. I can use either #12 or 14 insulated wire. I 'm using a ICOM 736 with an auto tune and I also have a MFJ 948. I have access to Belded 8214 and some twin lead. I would like to operate 80 and 160 my questions is what problems will I run into, should I invest in anothe balun? and most importanly any suggestions or ideas? Thanks. 73 GEORGE N1JGE From amsoft@epix.net Sun May 19 13:44:05 1996 Newsgroups: rec.radio.amateur.antenna From: Monty Wilson Subject: Re: Looking for plans for a small QRP tuner Message-ID: Date: Thu, 16 May 1996 14:53:24 GMT References: <4nek5v$o83@news1.slip.net> <4neogk$pov@crash.microserve.net> The thing you want to watch out for in QRP work is the addition of too many reactive components that cancel each other out, giving you a great match but using up what little power you have in the tuner. I heard at a Dayton forum several years ago that you can build a very simple matching device just by putting the braid straight through and attaching the center conductors to either end of an air variable. This only works if the antennas in question are on the long side; ie., if the only reactance to be compensated is inductive rather than capacitive. For example, he described a dipole cut for the bottom end of 80, and for 75 work you just open the air variable a little. But you can only have this luxury if you are at liberty to cut your antennas a little long. This raises an interesting question (well maybe interesting): if you put 20w into a tuner but only get 5w out of it, does it still count as QRP? -- .........Monty. mwilson@flex.net From amsoft@epix.net Sun May 19 13:44:06 1996 From: bjohn@cris.com Newsgroups: rec.radio.amateur.antenna Subject: MFJ 10 Band Antenna performance? Date: Mon, 13 May 96 15:11:37 GMT Message-ID: References: <4mq4ka$eeu@news1.demos.su> <831646102snz@microvst.demon.co.uk> Is anyone familiar with the performance of the MFJ-1798 Half-wave vertical antenna with coverage from 75/80 40,30,20,17,15,12,10,6 & even 2 meters? Thanks, Ben Johnson, KF4JEB From amsoft@epix.net Sun May 19 13:44:08 1996 From: p.sanders@groupz.net (Mica Sanders) Newsgroups: rec.radio.amateur.antenna Subject: Re: Mobile Antenna for 27Mhz Date: Tue, 07 May 1996 20:12:39 +0300 Message-ID: References: <4kpti6$jmd@news.ios.com> <317E5AD3.3483@gteais.com> <4lsa7q$ld7@news.ios.com> In article <4lsa7q$ld7@news.ios.com>, brianv1@village.ios.com wrote: > aor wrote: > >brianv1@village.ios.com wrote: > >> > >> I am trying to build a beam type of antenna for a 27Mhz mobile. Does > >> anyone have any models of this or ideas??? Even if you have formulas or > >> theory I would be very interested. > >> > >> Thanks > > > > > >One of the easiest ways to do this is by using two > >antennas and phasing them. One example would be to > >buy two 9' whip antennas and mount them 9' feet > >apart (1/4 wave on 27 MHz). Feed them in phase by > >using two equal runs of (odd 1/4 wave) 75 ohm coax > >from a tee-connector on your radio. The pattern > >will be broadside to the two antennas. With about > >3db of gain over a single antenna. > > > >You see truck drivers with two antennas, you don't > >see the phasing harness, and the pattern favors the > >front and back (broadside) by 3 db (double your > >radiated power) at the expense of side radiation > >(end-fire). The principles are the same. > > > >There are a lot of other things to consider > >assuming you can put two antennas 9' apart on a > >car, have good grounding, and a good ground plane. > >There are other methods by using 90 degrees phasing > >and 1/4 wave spacing... but that is another story. > >This resembles a 2-3 element beam pattern. > > > >It is a lot of fun to do, 75 ohm coax is cheap, and > >one centrally mounted antenna is usually better > >than multiple antennas for 99% of the population. > >Besides, how did you plan on turning this "beam" > >??? Hi Hi > > > >For 30 bucks, order the ARRL Antenna Handbook and > >read up on the subject. > > > >See ya, > > > >Al NW2M > > Thanks for the info. I'll look into that. I had heard that you can make > one of the antennas the hot and another the ground or backdoor. > Suppossedly the backdoor should act like a reflector. Al, I invested in the ARRL Antenna Book (several years ago) and (IMHO) found it to be of minimal value except in low band antenna designs. It is sorely lacking in phasing harness design and applications. I have yet to find a formula (or person) to describe how Decibel Products (premier supplier of commercial antennas) phases multiple folded dipoles (as many as 16 on UHF). I built an 8 dipole 465 MHZ unit using a DB-420 as a model and it performed exceptionally well (VSWR 1.05). I did not consider frequency/cable Velocity factor when building the harness but made sure that all 8 elements were fed using equal line lenghts from the feedpoint (total of 7 "tees" including feedpoint which was positioned at the center of the array). IMHO, it would seem logical that if the RF signal arrived at each element at the same time, all elements would resonate "in-phase" and the way to accomplish this is by equal lenghts of coax to each element from the feedpoint. Could you lend some insight on why the cable lenghts have to be in multiples of the frequency (even if center fed?), and what the "odd multiple" does for the design? Thanks, Paul WNQN319 From amsoft@epix.net Sun May 19 13:44:08 1996 From: micro@prometheus.hol.gr (George Micros) Newsgroups: rec.radio.amateur.antenna Subject: Need help! Fm Antenna and dipole construction. Date: 10 May 1996 00:52:48 GMT Message-ID: <4mu410$5ir@newsflash.hol.gr> I am looking for any plans for an FM Antenna or co-linear antenna with at least four dipoles. Need dipole distances and anything that might help me build it, (mathematical types will do). For use with a 500W fm transmitter. (for now). Any help will be appreciated. If possible please e-mail me at micro@prometheus.hol.gr From amsoft@epix.net Sun May 19 13:44:09 1996 From: w5gyj@primenet.com (Jim Bromley, W5GYJ) Newsgroups: rec.radio.amateur.antenna Subject: Re: Need source for antenna elements Date: 14 May 1996 01:59:03 -0700 Message-ID: <4n9i0n$k7j@nnrp1.news.primenet.com> References: <4n3b03$l7i@newsbf02.news.aol.com> Reply-To: w5gyj@primenet.com history67@aol.com (History67) wrote: >Can anyone tell me who carries alum, copper, or brass rods suitable for >use in the construction of 2 meter beam antennas? I have resorted to coat >hangers and old car antennas for my first few, but this will not due for >permanant uses. I have found that small-diameter brass and steel rods can be found at model-airplane hobby shops. The steel is referred to a "piano wire", is strong and flexible, but is not stainless so it needs to be painted. Just a hint. Jim Bromley, W5GYJ Glendale, Arizona From amsoft@epix.net Sun May 19 13:44:10 1996 From: Doyle Newsgroups: rec.radio.amateur.antenna Subject: Re: Need source for antenna elements Date: Tue, 14 May 1996 07:35:43 -0400 Message-ID: <3198700F.4FB3@ix.netcom.com> References: <4n3b03$l7i@newsbf02.news.aol.com> <4n9i0n$k7j@nnrp1.news.primenet.com> Jim Bromley, W5GYJ wrote: > > history67@aol.com (History67) wrote: > > >Can anyone tell me who carries alum, copper, or brass rods suitable for > >use in the construction of 2 meter beam antennas? I have resorted to coat > >hangers and old car antennas for my first few, but this will not due for > >permanant uses. > > I have found that small-diameter brass and steel rods can be found at > model-airplane hobby shops. The steel is referred to a "piano wire", > is strong and flexible, but is not stainless so it needs to be > painted. Just a hint. > > Jim Bromley, W5GYJ > Glendale, Arizona---------------------------------------- reply from jim KD4HUR IN FLORIDA John : check out your local welding supply house, I use aluminum welding rod for most of my 2 and 440 antennas at very reasonable cost also, they can be had in most diamaters you would usually want. Other metals brass , stainless ect are also avail this way... 73' KD4HUR From amsoft@epix.net Sun May 19 13:44:11 1996 From: norsan@bright.net Newsgroups: rec.radio.amateur.antenna Subject: Re: Need source for antenna elements Date: 16 May 1996 01:54:26 GMT Message-ID: <4ne1si$f1m@cletus.bright.net> References: <4n3b03$l7i@newsbf02.news.aol.com> <4n9i0n$k7j@nnrp1.news.primenet.com> To: news:4n9i0n$k7j@nnrp1.news.primenet.com w5gyj@primenet.com (Jim Bromley, W5GYJ) wrote: >history67@aol.com (History67) wrote: > >>Can anyone tell me who carries alum, copper, or brass rods suitable for >>use in the construction of 2 meter beam antennas? I have resorted to coat >>hangers and old car antennas for my first few, but this will not due for >>permanant uses. > >I have found that small-diameter brass and steel rods can be found at >model-airplane hobby shops. The steel is referred to a "piano wire", >is strong and flexible, but is not stainless so it needs to be >painted. Just a hint. > > >Jim Bromley, W5GYJ >Glendale, Arizona > Jim...I have found that for antenna elements the aluminum tubing found in hardware stores that is used to hold up clothes lines is perfect. It comes in 7 ft lengths, and cost less than $2 each. Cut of the "U" shaped wire at the end thats ment to hold up the line. May be a tad big for 2M but is great for 6 and lower Norm N8RGR From amsoft@epix.net Sun May 19 13:44:12 1996 From: RJD Newsgroups: rec.radio.amateur.antenna Subject: Re: No CODE No CW on HF Date: Sun, 12 May 1996 09:48:05 -0400 Message-ID: <3195EC15.7D5C@imperium.net> References: <4n3ugh$1936@mule2.mindspring.com> sco@sco-inc.com wrote: > > I might propose a rule change that says ... "If you want to operate > CW on the HF bands you must first pass a code test to update your > license. HOWEVER if you do NOT intend to operate CW then you do NOT > need to take or pass a code test." > > KE4IKT@sco-inc.com I'm sorry - are you referring to Ham Radio, or the proposed "Personal Radio Service"? I'm sure Radio Shack, KenComSu would support you wholeheartedly. So, I'm sure, would Technics, Pioneer, Sanyo, JVC, and anyone else who might have a vested interest in selling LOTS of HF rigs to unqualified "PRSers". I'm tired of everything being dummied down in this country. After memorizing the code, it took me just 45 minutes of receiving practice to pass the 5 WPM Novice code test. It just isn't that hard. Lets keep SOME standards in this country. God knows, the written test has become a joke. RJD From amsoft@epix.net Sun May 19 13:44:13 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: No CODE No CW on HF Date: 13 May 1996 02:03:37 -0400 Message-ID: <4n6jbp$ovn@newsbf02.news.aol.com> References: <3195EC15.7D5C@imperium.net> In article <3195EC15.7D5C@imperium.net>, RJD writes: >I'm tired of everything being dummied down in this country. After >memorizing the code, it took me just 45 minutes of receiving practice to >pass the 5 WPM Novice code test. It just isn't that hard. > >Lets keep SOME standards in this country. God knows, the written test >has become a joke. > >RJD Amen to that. The exams are all much easier now than they were earlier, including the code test. Look at what has happened to the USA edge on education thanks to "dumbing down" our schools. It seems the easier something is made, the more people whine about making it easier still. What's wrong with showing the little effort required? 73 Tom From amsoft@epix.net Sun May 19 13:44:14 1996 From: burch@netline.net (Burch Akin) Newsgroups: rec.radio.amateur.antenna Subject: Opinion? Date: Mon, 13 May 1996 13:57:10 GMT Message-ID: <4n7f4m$mik@tesla.netline.net> I am going to be moving to a new location soon. I have found an area that has no antenna restrictions. The only problem I see is there is a big warehouse/building to the west of me. It is about 1/3 of a mile away. All the other directions from the house are free from any tall structures within a couple of miles. Does anyone have an opinion about how this structure will effect my singal? I opperate mainly on 6 meters, 2 meters, 222, 432 and 1296. My antennas will be up about 50' or so and I really don't know the height of the building. I am hoping that my take-off angle will be overcome the building. I live on the west coast of Florida and the only thing I can work west of me is on the other side of the Gulf which takes some type of special conditions (tropo, e-skip, etc.) Any opinions would be greatly appreciated. KE4ZQV From amsoft@epix.net Sun May 19 13:44:15 1996 From: moritz@ipers1.e-technik.uni-stuttgart.de () Newsgroups: rec.radio.amateur.antenna Subject: Re: Opinion? Date: 14 May 1996 11:21:26 GMT Message-ID: <4n9qbm$20dm@info4.rus.uni-stuttgart.de> References: <4n7f4m$mik@tesla.netline.net> >Does anyone have an opinion >about how this structure will effect my singal? Noone who has not seen the building will really be able to help you there. As a rough guideline, if the building is higher than your antenna, on 50 the attenuation will be not too serious, but 1296 gets wiped out much in the same way as light. 73, Moritz DL5UH From amsoft@epix.net Sun May 19 13:44:16 1996 From: lavallee@island.net (Gerry Lavallee) Newsgroups: rec.radio.amateur.antenna Subject: Question-railroad antennae Date: 10 May 1996 04:38:44 GMT Message-ID: I was wondering if someone could enlighten me. I am a rail fan and have noticed different radio antennae on locomotives. I am curious why different shapes are required as the frequencies used by railroads are in the same bandwidth (around 160 megahertz) I understand how a "whip" antenna radiates out a signal & captures a signal. I have an idea why a base plane is used underneath a whip antenna. Anyway, in the past & now in the present I have seen; 1. An antenna shaped like a gong type bell 2. " " " " a railing along the loco hood (induction?) 3. " " " " a fire cracker 4. " " " " an ice skate (called "Sinclair" type) 5. " " " " a tin can The Sinclair type is almost universally used in Canada but in the states the antennae used seem almost random, even on the same railroad From amsoft@epix.net Sun May 19 13:44:17 1996 Newsgroups: rec.radio.amateur.antenna From: n4lq@iglou.com (David Chamberlin SLIP/PPP) Subject: Re: R7000? Message-ID: References: <4nhqhe$k2b@ecuador.it.earthlink.net> Date: Sat, 18 May 1996 02:53:45 GMT I saw the R7000 today at Dayton. All I can tell you is that it appears to be heavier in construction. The traps are enclosed now and look more substantial but who knows? That's a lot of bux for a vertical. Roger J. Buffington; AB6WR (rogerjb@earthlink.net) wrote: : Has anyone used the new Cushcraft R7000? I'm curious as to how it : performs. I'm also interested in knowing how it handles high power at a : near 100% duty cycle, as for SSTV or digital operations (Amtor/Pactor/RTTY). : The R-7 was notorious for blowing traps at even modest power levels. (The : R5 does not suffer from this problem, in my experience.) Did the R7000 : cure this problem? : And how is performance? Anyone compare it to other verticals? : Roger J. Buffington : AB6WR : USC Law School Class of '97 : rogerjb@earthlink.net : "I want to die peacefully, in my sleep, like my grandfather. : Not screaming, and in terror, like his passengers." -- Steve Ellington N4LQ@IGLOU.COM Louisville, Ky From amsoft@epix.net Sun May 19 13:44:17 1996 From: Rich Griffiths Newsgroups: rec.radio.amateur.antenna Subject: Re: Radio Shack Tandy Coax any good? Date: Thu, 16 May 1996 12:29:33 -0400 Message-ID: <319B57ED.3476@monmouth.com> References: <4ndvve$d0g@mule1.mindspring.com> David L. Thompson wrote: > > "John T. Young" wrote: > > >Anyone have any opinions on the quality of Tandy RG8/U coax compared to > >the other main brands such as Belden, etc.? Thanks de John, KI7JB > > According to my contacts at Tandy HQ in Dallas the RS coax since the > early 90's is 96% braid and close to Belden etc. I use their RG8 on > two antennas with good success. They also have a parts division Tandy > national Parts. > > Dave K4JRB I bought RG-58 and RG-59 from RS a couple of years ago that couldn't have been more than 60% coverage. I haven't checked the RG-8, but then "Fool me once, shame on you ...." I won't make that mistake again. I don't fault RS on everything, as some do. I think they do sell some good stuff. But coax is not on the list. Rich W2RG From amsoft@epix.net Sun May 19 13:44:18 1996 From: bstevens@slate.Mines.EDU (Brian D. Stevens) Newsgroups: rec.radio.amateur.antenna Subject: Re: Request comments - Larson mag-mounts Date: 16 May 1996 15:04:43 GMT Message-ID: <4nfg6b$11ca@magma.Mines.EDU> References: <4ndrjl$c6u@excelsior.flash.net> : I am requesting comments about Larson Antenna mag-mounts. I have : experienced with two different NMO-MM mag-mounts that corroded inside and : became disconnected (electrically) from the capacitive coupling surface : on the base - resulting in high SWR. Anyone else experience this? Mine kept falling off at highway speeds and were destroyed before they had time to corrode. B From amsoft@epix.net Sun May 19 13:44:19 1996 From: "Michael C. Maguire" Newsgroups: rec.radio.amateur.antenna Subject: Request for Info on M2 Antenna Controller Date: 7 May 1996 18:48:39 GMT Message-ID: <4mo5u7$lme@client2.news.psi.net> I have a Model RC2800-PRK Dual Controller from a company called M2 or M-square d (depending on how you read the logo). The controller connects to an az/el mount suitable for coarse pointing of a helical antenna for satellite tracking . Unfortunately, I do not have a complete manual set for either the controller o r the az/el drives. Does anyone have contact information for either M2 or a sales rep for M2? Any combination of corporate address, phone, fax, email or WWW address would be appreciated. Thanks in advance. Regards, mcm -- Michael C. Maguire Systems Engineer Earthwatch Inc. - http://www.digitalglobe.com/ Tel: 510-417-2044 Fax: 510-417-2045 Email: mmaguire@ewi.com From amsoft@epix.net Sun May 19 13:44:20 1996 Newsgroups: rec.radio.amateur.antenna From: ao779@torfree.net (CB Smith) Subject: Rogers Antenna System Message-ID: Date: Sun, 12 May 1996 00:19:19 GMT Does anyone have details on this antenna ? Apparently built by the US military in the 1930's and is static-free. Any ideas ? de Brian ve3ex ao779@torfree.net From amsoft@epix.net Sun May 19 13:44:21 1996 From: Ed Guzis Newsgroups: rec.radio.amateur.antenna Subject: Re: RS telescoping masts? Date: 13 May 1996 03:54:25 GMT Message-ID: <4n6bph$k5a@tribune.concentric.net> References: <4n54i5$ki0@omnifest.uwm.edu> > >Does anyone out there have any personal experience with those telescoping >masts from Radio Shack? > >TNX ES 73, > >Rick WB9GYT >Milwaukee, WI Rick, Suggestion --- buy one 10 feet longer than you need and discard the top section -- the Radio Shack push ups are a little light duty -- using only the lower sections helps. Regards, Ed Guzis W9TW From amsoft@epix.net Sun May 19 13:44:22 1996 From: Clint.Bradford@bbs.woodybbs.com (Clint Bradford) Date: 07 May 96 19:38:00 Newsgroups: rec.radio.amateur.antenna Subject: Sale Message-ID: <6b0_9605080929@woodybbs.com> >>Hi Tom here... I have for sale 2 Regency 16ch programable mobiles. INTERNET TIP #4 - If the Conference/Newsgrou doesn't have the word, "SALE," in its title, it is probably inappropriate to post FOR SALE messages in it. There -IS- a very active FOR SALE area for you on the same system you posted this message. Please prepare for a little flack from those who will not-as-gently-as-I-have remind you of the Conference Posting rules. clint.bradford@atdbbs.com ... ATTENTION to Details BBS - 909-681-6221 - REACT/GMRS/AMATEUR RADIO --- * TLX v4.00 * * wcECHO 4.1 ~ AR-Net: ATTENTION to Details * Mira Loma, CA * 909-681-6221 -- |Fidonet: Clint Bradford 1:2619/228 |Internet: Clint.Bradford@bbs.woodybbs.com | | Standard disclaimer: The views of this user are strictly his own. From amsoft@epix.net Sun May 19 13:44:22 1996 From: Clint.Bradford@bbs.woodybbs.com (Clint Bradford) Date: 11 May 96 02:00:00 Newsgroups: rec.radio.amateur.antenna Subject: Sale Message-ID: <6e2_9605111440@woodybbs.com> >>Hi Tom here... I have for sale 2 Regency 16ch programable mobiles. INTERNET TIP #4 - If the Conference/Newsgrou doesn't have the word, "SALE," in its title, it is probably inappropriate to post FOR SALE messages in it. There -IS- a very active FOR SALE area for you on the same system you posted this message. Please prepare for a little flack from those who will not-as-gently-as-I-have remind you of the Conference Posting rules. clint.bradford@atdbbs.com ... ATTENTION to Details BBS - 909-681-6221 - REACT/GMRS/AMATEUR RADIO --- * TLX v4.00 * * wcECHO 4.1 ~ AR-Net: ATTENTION to Details * Mira Loma, CA * 909-681-6221 -- |Fidonet: Clint Bradford 1:2619/228 |Internet: Clint.Bradford@bbs.woodybbs.com | | Standard disclaimer: The views of this user are strictly his own. From amsoft@epix.net Sun May 19 13:44:23 1996 From: billv21572@aol.com (BillV21572) Newsgroups: rec.radio.amateur.antenna Subject: Re: shortend radials Date: 9 May 1996 02:02:45 -0400 Message-ID: <4ms1q5$7dp@newsbf02.news.aol.com> References: <4mqp0u$5ok@nadine.teleport.com> I've got 4 little kids and a dog, and if I laid my radials out directly on the surface of the lawn, they would hand me a ball of wire at the end of one weekend. Unfortunately, I have a "multi-use" backyard, and even though Daddy loves his hobby, my kids don't love me much ;) Bill ka9hln Bill Vanstralen KA9HLN St. Paul, MN (612)688-2552 billv21572@aol.com From amsoft@epix.net Sun May 19 13:44:24 1996 From: Lennart Nilsson Newsgroups: rec.radio.amateur.antenna Subject: Re: shunt fed crank up? vs inverted L? Date: 13 May 1996 10:33:28 GMT Message-ID: <4n735o$rnp@simba.lejonet.se> References: <4mqv8l$s2d@news1.t1.usa.pipeline.com> To: ke6ber@usa.pipeline.com I would start with she shunt feed. Why not use a length of old detoriated coax cable, RG-8 or RG-11, using the shield as a fat conductor. Connect to the tower at the top below the rotor and let the coax run down through holes in isolating material attached to one ft spacers. When the tower is all the way up you can tighten the bottom end of the coax to a feedthrough isolator and have the matching components in a waterproof box. You will get impedance transformation because the gamma "rod" is much thinner than the tower. Expect several hundred ohms on 160 m, and that will keep your ground losses down. I have had such an arrangement on a 65 ft fixed tube mast loaded with a 2 el Quad. Don=B4t forget radials! 73 de Lennart, SM5DFF From amsoft@epix.net Sun May 19 13:44:26 1996 From: grhosler@mmm.com (Gary Hosler - KN0Z) Newsgroups: rec.radio.amateur.antenna Subject: Re: Shunt load a tower Date: Wed, 08 May 1996 13:45:19 GMT Message-ID: <4mq8or$pau@dawn.mmm.com> References: <3180288D.1693@p30.s501.c41.k12.wv.us> a_simons@p30.s501.c41.k12.wv.US (Anthony Simons) wrote: >Hello all, Where can I find the best info on shunt loading a tower. I have >a ROHN BX-64 (64' self supporting) with a 3 Ele tri-bander with a dual band >2m/70cm vertical on top. The tower is grounded on all three legs with an 8' >rod with 1/2 copper tubing to each leg. I would like to use the system on >40/80 Meters. Any and all suggestions appreciated. > Thanks & 73, de Anthony KC8BK Sorry to have taken so long to respond to your post but I knew I had an article stashed away on a similiar installation. The August 1990 issue of CQ Magazine had an article (on page 46) by Gary Nichols - KD9SV, and Lynn Gerig - WA9GFR. The article described shunt feeding a 70 foot tower with a TH6-DXX on top. Sounds like a VERY similiar instalation to what your are proposing, and this article also included the 160M Top Band. I plan to shunt feed my 100 foot Rohn 25G (with 15 feet of mast out the top) this Summer in preperation for the Fall/Winter season on Top Band. Good luck on your project. 73 & GUD DX OM de KN0Z Gary in Wyoming, MN Opinions expressed herein are my own and may not represent those of my employe r. From amsoft@epix.net Sun May 19 13:44:26 1996 Newsgroups: rec.radio.amateur.antenna From: John Van Subject: Simple 17M 3ele Yagi Message-ID: Date: Sat, 18 May 1996 13:53:44 GMT Can anyone give me a simple design layout for a 3ele 17M antenna? I've looked thru my past issues of QST and all I find are multi-band 12-17 or those requiring Traps.....Not what I'm looking for. Thanks in advance for any help........John / N1ONM From amsoft@epix.net Sun May 19 13:44:27 1996 From: Edward Oros Newsgroups: rec.radio.amateur.antenna Subject: Re: Simple 17M 3ele Yagi Date: Sat, 18 May 1996 10:51:39 -0400 Message-ID: <319DE3FB.7FE0@ix.netcom.com> References: Yes... Try http://www.4w.com/ham/antenna you can have an antenna designed there. Ed-- AC3L John Van wrote: > > Can anyone give me a simple design layout for a 3ele 17M antenna? I've > looked thru my past issues of QST and all I find are multi-band 12-17 or > those requiring Traps.....Not what I'm looking for. > > Thanks in advance for any help........John / N1ONM From amsoft@epix.net Sun May 19 13:44:28 1996 From: William R Liporace Newsgroups: rec.radio.amateur.antenna Subject: TH6 Info Date: Thu, 16 May 1996 10:24:46 -0400 Message-ID: Is there a number for Telex/HyGain ?? I would like to check out prices of their SS hardware for the TH6 or maybe an upgrade kit to a TH7. I am getting ready for that first tower project and I want everything to be ready to go up. TNX 73 Will KB2HUN William Liporace KB2HUN kb2hun@wizvax.net 325 Mountain Street KB2HUN @ K2TR (yccc packet cluster) Albany, NY 12209 KB2HUN @ WA2PVV (NEDA) 518-449-1397 home 518-471-2837 From amsoft@epix.net Sun May 19 13:44:29 1996 From: aor Newsgroups: rec.radio.amateur.antenna Subject: Re: Tracking Line Noise * one solution ! Date: Sun, 12 May 1996 15:28:17 -0400 Message-ID: <31963BD1.5072@gteais.com> References: <4n2p31$rbv@crl9.crl.com> To: "Henry B. Smith" > > I want to track down some line noise. > > I have seen the power company folks using a receiver with a small yagi. > > Anybody know what frequency they use for tracking noise? What kind of > receiver is best for tracking line noise? > > Smitty, NA5K > -- > Henry Smith (hbs@crl.com) Henry, We had the power company come to one of our meetings to discuss this subject. It was a packed house!!! They have a tool, which is on the end of a 10' PVC tube, that has two sensors on the top. One is a microphone and the other a simple AM detector. All powered by an internal battery, so nothing conductive comes even close to the operator. The sound travels down this tube to the operator who can 'hear' what's going on. Really neat!! I use a simple $10 AM radio tuned to 530 AM. Each power pole has a gound wire running into the soil. I hold the radio next to the ground wire, and on really bad poles, you hear lots of noises. I simply record the number stamped on the pole and make a telephone call to the interference staff at the power company. 73, and best of luck. Al NW2M From amsoft@epix.net Sun May 19 13:44:30 1996 From: darrellk@internetland.net (Darrell kimball) Newsgroups: rec.radio.amateur.antenna Subject: variable capacitor Date: Tue, 14 May 1996 14:39:35 GMT Message-ID: <31989ab5.12385328@news.internetland.net> anyone know where I can buy or "get" a 3 section, 100 pf variable capacitor? High voltage not needed.Thanks E-Mail darrellk@internetland.net From amsoft@epix.net Sun May 19 13:44:31 1996 From: Miguel Angel Simoes Santiago Newsgroups: rec.radio.amateur.antenna Subject: Vertical 40M antenne Date: Mon, 13 May 1996 19:07:03 +0000 Message-ID: <31978857.9900D46@mail.telepac.pt> Is it possible to use my tower as a 1/4 Lambda vertical antenna? I was thinking to match impedance with a GAMMA Match, but I'm not really sure it will work. Any suggestions? / / / / /| / | | | | | || || GAMMA -------------------/ Gound Radials sticked on the earth Miguel Santiago CT2GDD radimprensa@mail.telepac.pt From amsoft@epix.net Sun May 19 13:44:32 1996 From: tomb@lsid.hp.com (Tom Bruhns) Newsgroups: rec.radio.amateur.antenna Subject: Re: Very small Antennas Date: 8 May 1996 18:29:28 GMT Message-ID: <4mqp68$gep@hpcvsnz.cv.hp.com> References: <31900CAA.3671@ibm.net> Doug Person (ki6bq@ibm.net) wrote: : Now I want to reduce a 40 meter antenna to about 25 ft. That's all the spac e I : have, if I want 40, it must fit in the 25 foot available in the attic. I gu essed : lucky with the 20. How can I calculate the loading coils for the compact 40 ? : I made one using aluminum tubing and fiberglass coil forms hoping to have so mething : I can run my 600 amplifier into. My guess was way off - 16ft #14 on 1.25od form and : about 10 ft of 1" tubing per leg - resonates at 9.745. I can continue to mo dify : deminsions until I get it right - but that is a a lot of attic climbing. An y : suggestions? Yes, my standard reference for just this sort of thing is an old "Ham Radio" magazine article by Joseph Boyer, "The Antenna-Transmission Line Analog." It was in the April and May, 1977, issues. It goes into exactly how to make good engineering-accuracy calculations of loading coils anywhere along the antenna, and gives you a lot of appreciation for how linear antennas work, and why one loading-coil position is better than another. Since you likely will have trouble finding these issues of Ham Radio, I have a standing offer to send photocopies of the article for a SASE and photocopy costs. It's 24 pages, including some relevant pages of one of the references which plots antenna impedance versus length and wire diameter (necessary info to fully use the Boyer article). Send me email if interested. (Design of very short vertical + matching network deleted.) : Here's the bottom line: I have no education in this stuff. I'm just guessi ng at what works. : Does this really do something or am I just tuning a coax longwire? Can I do anything to improve : this concept? Anyone have suggestions, thoughts, ideas, anything at all the y wish to contribute? I'm impressed that it looks like basically a pretty decent design for easy duplication by hams. Things to consider: the feedpoint impedance of a very short antenna is a very small resistance in series with quite a bit of capacitive reactance. That means you need a lot of current to get radiation (from the low resistance), and a high voltage, to get the current through the capacitive reactance. It's hard to make a low loss matching network for that; pay attention to anything that will be lossy. Look up info on optimum coil geometry. Avoid insulations at the high impedance points which might be lossy (hint: Teflon or polystyrene are much, much less lossy than Nylon). Provide _some_ kind of reasonably low loss ground system (several heavy radial wires across the roof?), and make the actual antenna radiator as long as you can (to raise the resistance) and as large diameter as you can (to cut losses from the high current flowing on the surface of the antenna). (Another hint: the matching network, if it's low loss, will be rather high Q, which implies narrow bandwidth. If you are getting much bandwidth, it's a clue that you have a lot of losses besides the radiation from the antenna...) I'd like to encourage you to keep learning. You are making some good early guesses, and with some understanding behind the guesses, you will probably come up with some really neat -- and reasonably efficient -- designs. -- Cheers, Tom tomb@lsid.hp.com From amsoft@epix.net Sun May 19 13:44:34 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Very small Antennas Date: Thu, 09 May 96 09:25:09 GMT Message-ID: <4msdjf$nr@nadine.teleport.com> References: <31900CAA.3671@ibm.net> <4mqp68$gep@hpcvsnz.cv.hp.com> In article <4mqp68$gep@hpcvsnz.cv.hp.com>, tomb@lsid.hp.com (Tom Bruhns) wrote: > [lots of excellent advice]. . . >. . . (hint: Teflon or polystyrene are much, much >less lossy than Nylon). . . I was looking in some references recently for other low-loss materials, and polypropylene looks from the specs to be very good also. And it has a relatively low dielectric constant. One big minus is that it's very susceptible to UV deterioration, so I wouldn't use it outside for an extended period unless you can keep the sunlight off of it. Does anyone have any experience with it as a high-quality insulator or have any information that would confirm or refute the premise that it's good? (This is the stuff you can buy at any discount store as "floating rope".) Roy Lewallen, W7EL From amsoft@epix.net Sun May 19 13:44:36 1996 From: graham@southlin.demon.co.uk (Graham Seale) Newsgroups: rec.radio.amateur.antenna Subject: Re: Very small Antennas Date: Thu, 09 May 1996 20:38:39 GMT Distribution: world Message-ID: <19960509.203839.14@southlin.demon.co.uk> References: <31900CAA.3671@ibm.net> Reply-To: graham@southlin.demon.co.uk In message <31900CAA.3671@ibm.net> Doug Person wrote: > I have made a 20 meter dipole that is 22 ft instead of the usual 33 ft to > fit between two conveniently located trees. This gives me a second antenna > for 20, 90 degrees from the original favoring north/south signals. I used s ome > pvc pipe and about 8 ft of #14 insulated stranded wire close wound to make a > loading coil for each leg - mounted more or less in the legs center. With 1 00 > watts it works great. SWR on the full size 20 is under 2:1 edge to edge. On the > loaded 20 I loose about 100 khz of bandwidth and otherwise find it comparabl e. Hi Doug Before you get too entangled in dissipating the highest current contributions from your antenna in loading coils, try a very simple approach. An antenna shorter than resonance will still deliver radiation energy, but will appear capacitive at the feedpoint. To match a feed to it you need to add inductance to tune out the capacitive component leaving you with something like a unity power factor. This "matcher" is your loading coil. My instinct would be to duck the need for such lossy narrow band things. I would leave the full 33ft of wire in the dipole, but arrange the middle 22ft to be horizontal, and let 5.5 feet dangle down vertically at each end. If this be inconvenient, then fold back the 5.5 foot dangly into a loop back to the support insulator. Do not let the high voltage end connect back to support point. The idea is to force the current to go the distance down the wire the full 33ft. The folded back bit is the beginnings of an *end* loading coil, and will affect the resonant length a bit, but we resist madly making it any more of a loading coil than we absolutely have to. This way, you only mourn the loss of the very little contributions from the ends. If they dangle down, they provide a little vertical component. If you fold them back, the folded part cancels some in the descending part anyway. In practice you will probably find you can fold up the ends of a resonant dipole with very little effect on the tuning, but do it as you would any new dipole - start with a bit extra splaying off the ends, and tune it to resonance by cutting off some inches each side and checking the resonance with a dip meter/noise bridge or somesuch. 73's G4WNT -- Graham Seale From amsoft@epix.net Sun May 19 13:44:37 1996 From: labenz@ix.netcom.com(David M. Arruzza) Newsgroups: rec.radio.amateur.antenna Subject: WB3U/W7EL/W7XC & OTHERS Date: 18 May 1996 15:36:06 GMT Message-ID: <4nkqp6$93g@dfw-ixnews3.ix.netcom.com> need your input: due to rearrangement of shack i cannot feed my center fed hertz antennas directly at the link coupled tuners. I may have to go to a remote balun and an spc,L or T net coupler. Operating position is 20 feet from access point. Antennas to be used: 270' center fed with 450 ohm line 160/80/40 88' center fed with 600 ohm line 40/30/20/17 130' center fed with 450 ohm line 80-20 70' center fed with 450 ohm line 40-10 feedline lengths are 85' power output 110 watts 830S Gentlemen your comments and suggestions 73 Dave WA1UUD I am not crazy about the remote balun/coax/tuner combo but i need some more options. I have tried bringing the feedline all the way to the tuners but i have had reports of RF on the signal and rf floating around the shack. Operating power is 110 watts output with an 830S From amsoft@epix.net Wed May 22 18:46:12 1996 From: Elitecon@cris.com (ELITECON) Newsgroups: rec.radio.amateur.antenna Subject: pro-2037(radio shack) Date: 20 May 1996 09:37:34 GMT Distribution: 99 Message-ID: <4npegu$f5n@tribune.concentric.net> Summary: for cellular receptions Keywords: whats the best transportable antenna please help From amsoft@epix.net Wed May 22 18:46:13 1996 From: @wtp.net (MSBF) Newsgroups: rec.radio.amateur.antenna Subject: MFJ Hi-Q Loop antenna Date: 20 May 1996 03:43:50 GMT Message-ID: <4noppm$olg@wtpprod1.wtp.net> Has anyone used this antenna and if so, what do you think of it? WT5C Jim Edlin From amsoft@epix.net Wed May 22 18:46:14 1996 From: jyfourri@simplet_3.univ-lr.fr (FOURRIER Jean-Yves) Newsgroups: rec.radio.amateur.antenna Subject: plot a nec calculation Date: 17 May 1996 17:10:21 GMT Message-ID: <4nibtt$ljd@hpuniv.univ-lr.fr> Hello , i am looking for a prog to plot the nec calculation (bandwith,elevation and azimut pattern) , i you know a freeware with this possibility , please send me a E-mail thanks Dominique F1DOQ From amsoft@epix.net Wed May 22 18:46:15 1996 From: eiringo@aol.com (EIRINGO) Newsgroups: rec.radio.amateur.antenna Subject: Stereo radio antenna quiry Date: 17 May 1996 16:02:47 -0400 Message-ID: <4nim17$j9s@newsbf02.news.aol.com> Reply-To: eiringo@aol.com (EIRINGO) I have a SWR and scanner fed thru an AlfaDelt antenna switch and grounded 50 ohm coax. No problems. Question, how to connect a stereo receiver with holes for 75 and 300 ohms? Why does connecting both ends of a FM dipole decrease sensitivity? Any help appreciated. Cody From amsoft@epix.net Wed May 22 18:46:15 1996 From: drw1@aol.com (DRW1) Newsgroups: rec.radio.amateur.antenna Subject: Re: 80mtr loop (cloud warmer) Date: 19 May 1996 10:54:30 -0400 Message-ID: <4nncn6$52u@newsbf02.news.aol.com> References: <4ngmqn$1br@news.paonline.com> Reply-To: drw1@aol.com (DRW1) I installed a full wave 80 mtr loop about 2 months ago. It loads well (with a tuner) form 80 - 10. If it ever goes down I will replace it with on cut to 40 mtr., it takes up a little less space, but, as it stands now, I wish I would have discovered this thing a long time ago. Don From amsoft@epix.net Wed May 22 18:46:16 1996 From: David Rice Newsgroups: rec.radio.amateur.antenna Subject: Fomula to get SWR from foward and reflected power Date: Mon, 20 May 1996 17:08:19 -0700 Message-ID: <31A10973.1899@wsi.net> Reply-To: dave@wsi.net I have a watt meter that reads foward and reflected power. The meter does not measure SWR nor does the manual offer any way to calculate SWR. Is there a formula that given foward and reflected power would give me SWR. From amsoft@epix.net Wed May 22 18:46:17 1996 From: Edward Lawrence Newsgroups: rec.radio.amateur.antenna Subject: Re: DDRR antenna - reference: RE flagpole antennas Date: 20 May 1996 16:08:16 GMT Message-ID: <4nq5dg$dqk@fcnews.fc.hp.com> References: <4nfi1d$imv@mksrv1.dseg.ti.com> <4nii04$pq2@lynx.unm.edu> Last I knew, DDRR stood for 'Dual Discontinuity Ring Radiator'. The basic antenna was a DRR, or Discontinuity Ring radiator, which is what Jim is describing. The theory is idiotic! However, this antenna does work, which just shows that you can get practical results even with a faulty theory. This antenna is really a variation of a slot antenna, bent into a circle. From amsoft@epix.net Wed May 22 18:46:18 1996 From: brown@auburn.campus.mci.net (Phil Brown) Newsgroups: rec.radio.amateur.antenna Subject: Using 2m Colinear for Base Antenna? Date: Fri, 17 May 1996 21:49:10 GMT Message-ID: <4nil7v$g6o@news.campus.mci.net> Reply-To: brown@auburn.campus.mci.net After several inactive years, I am getting back into hamming. I have forgotten most of what I knew about antennas, it seems. I have an unused 2 meter Hustler coaxial colinear antenna, formerly used mobile. Has anyone had any success using this antenna as a vertical base antenna? How did you mount it, and did you use any counterpoise? Thanks. -Phil N4COD From amsoft@epix.net Wed May 22 18:46:19 1996 From: anthonys@ix.netcom.com(Anthony Severdia) Newsgroups: rec.radio.amateur.antenna Subject: Re: Need plans for SHORT 40 meter antenna Date: 21 May 1996 08:39:08 GMT Message-ID: <4nrvfc$jcq@dfw-ixnews4.ix.netcom.com> References: <4nrel3$qvn@wormer.fn.net> In <4nrel3$qvn@wormer.fn.net> lebbin@mail.fn.net (Mark Lebbin) writes: > >I am moving into a duplex and I need a very short antenna so I can stay >on the ham bands. Any suggestions? > Yah ...looking for a Magic Answer? ...with no criteria? Ya better pound the the books a bit! ...to see what fits. From amsoft@epix.net Wed May 22 18:46:20 1996 From: travisp@ix.netcom.com (Gerald Phillips) Newsgroups: rec.radio.amateur.antenna Subject: Plans wanted for an inexpensive 2m antenna to go outside. Date: Tue, 21 May 1996 22:47:29 GMT Message-ID: <4nth5q$78c@dfw-ixnews8.ix.netcom.com> I am looking for plans/information for an inexpensive 2m antenna that can be mounted outside. Please email me if you have anything. Thanks. KE4MBD - Travis From amsoft@epix.net Wed May 22 18:46:20 1996 From: daddydavid@aol.com (DaddyDavid) Newsgroups: rec.radio.amateur.antenna Subject: Re: 80mtr loop (cloud warmer) Date: 22 May 1996 08:54:19 -0400 Message-ID: <4nv2pr$fg4@newsbf02.news.aol.com> References: <4ngmqn$1br@news.paonline.com> Reply-To: daddydavid@aol.com (DaddyDavid) There is a good practical discussion in W1FB Antenna NB. I've built several. Simply. PVC insulated wire allows one to reduce the size by .66. Full size is better. Very forgiving. Symmetry is impt. Use a Johnson Match Box for best multibad performance. Give it a try! de N9PVF From amsoft@epix.net Wed May 22 18:46:21 1996 From: ebuchanan@gnn.com (Ed Buchanan) Newsgroups: rec.radio.amateur.antenna Subject: 6 M Antenna Tested Date: Sun, 19 May 1996 20:19:07 Message-ID: <4nop5l$7t6@news-e2c.gnn.com> Saturday 5-18-96 Cubex Co. tested their new 4 element 6 meter quad which is designed to be a sideband antenna. This antenna has over 12 dbd gain, this is due to the relatively narrow bandwidth (50.0-51.0 Mhz.) vswr less than 1.7-1 and resonant at 50.3 the resonant point can be changed slightly (.5 Mhz) with the unique Cubex adjustable feed point. Front to back was 15-18 db with a clean pattern and no strange lobes. This antenna will be available by the first of June, 1996. "73" Ed KN6CL From amsoft@epix.net Wed May 22 18:46:22 1996 From: "Andrew D. Lawlor" Newsgroups: rec.radio.amateur.antenna Subject: Re: Info wanted on On-Glass Dual Band Ants. (Larson, Radio Shack, etc.) Date: Fri, 17 May 1996 16:13:46 -0500 Message-ID: <319CEC0A.F6@concentric.net> References: <4nhhn2$9h8@newsbf02.news.aol.com> Reply-To: adlawlor@concentric.net To: Cobra295 Regarding the Radio Shack "dual band" glass mount 2M/70cm antenna: It isn't. Well, okay, it is, sort of. You can only use it for one band or the other, not both. If you want to switch from 2m to 440 you have to add a radial & re-tune the antenna. I bought it and installed it before I realized that it wouldn't work on both bands without a modification each time. So, for 40 bucks you get one or the other. (And, as a side note, on 2M you lose an incredible amount of gain when compared to a 5/8 wave 2m mag-mount). I would give it two thumbs down. Spend the extra money and get a true dual band antenna. 73 KC6NMD Andy From amsoft@epix.net Wed May 22 18:46:23 1996 Newsgroups: rec.radio.amateur.antenna From: griffin@jgfl1.allcon.com (Jens Goerke) Subject: Re: Foil Shield Coax Message-ID: References: <0000121B00000CF7@prostar.com> Date: Sat, 18 May 1996 14:59:32 GMT Cougercat (cougercat@prostar.com) wrote: > Does anybody know where one can pick up coax that has a foil shield as well > as a copper braided shield? Something simular to Larsen Anttenna Co. > "Digi-Shield" coax but NOT from Larsen? I need it in RG-58 and RG-8 size. I've seen the RG-58 variety used for high-quality 10-base-2 EtherNet installations, so you might give it a try. It's kind of stiff, though. Hope that helps, Jens, DB9LL -- Do _YOU_ know where your towel is? From amsoft@epix.net Wed May 22 18:46:24 1996 From: Ed Sikorski Newsgroups: rec.radio.amateur.antenna Subject: WTB: Fiber Glass Pole for Boom Date: Wed, 22 May 1996 11:15:50 -0400 Message-ID: <31A32FA6.4F1@serv01.net-link.net> Thanks for taking the time to read this. I am looking for a fiber glass pole 1.5" or 2" in diameter and 32' - 35' long to be used as a boom. I want to build an 2 element 80m dipole paristic array that is describe d in the Low Band DXing book by ON4UN. If you know were I can purchase such an item please let me know via email at edsikor@serv01.net-link.net. If you have any options on boom material please let me know via email. 73 ed AA8PA From amsoft@epix.net Wed May 22 18:46:25 1996 From: eiringo@aol.com (EIRINGO) Newsgroups: rec.radio.amateur.antenna Subject: Stereo Antenna Date: 20 May 1996 12:03:06 -0400 Message-ID: <4nq53q$pob@newsbf02.news.aol.com> Reply-To: eiringo@aol.com (EIRINGO) By SWR I mean a short wave receiver (HF150). Connecting both ends of a300 ohm line FM dipole into a stereo's 300 ohm holes wipes out all but the strongest signals. Such radios have holes also for 75 ohms also, but no jacks. I wired a 239 jack and have tried straight to the 300 ohm leads inside the radio, as well as thru a standard 75/300 converter. In both cases no sound from the lead, only from a small AM loop, also commonly supplied with these stereo radios. Maybe such radios are easily overloaded? The mono FM on my RS2006 is very good, using the outside antenna setup. Cody From amsoft@epix.net Wed May 22 18:46:26 1996 From: ekays@harrahs.com (Eugene Kays) Newsgroups: rec.radio.amateur.antenna Subject: Mounting Advice Date: 17 May 1996 17:20:31 GMT Message-ID: <4nicgv$ooo@netserver.harrahs.com> I am recently purchased a new Dodge RAM pickup. I need ideas on how to get a mobile antenna mounted. The antenna I have and had planned to reuse is a Diamond 7900. I lillte taller than a 5/8 2M. I have a camper top on it and this means no edge area of the bed is available. I don't want to use a glass mount installation. My main operation in the mobile is on simplex and I do not want to give up on the range obtained by the Diamond. Any ideas would be welcome. Thanks es 73, Gene ekays@harrahs.com KA5ALN From amsoft@epix.net Wed May 22 18:46:26 1996 From: cmoore@scorpion.ch.intel.com (Cecil A. Moore~) Newsgroups: rec.radio.amateur.antenna Subject: Re: Testing a balun with a noise bridge question Date: 21 May 1996 15:44:52 GMT Distribution: world Message-ID: <4nsodk$1kod@chnews.ch.intel.com> References: <4noats$q2s@steel.interlog.com> <4np283$hvr@nnrp1.news.primenet.com> In article <4np283$hvr@nnrp1.news.primenet.com>, Cecil Moore wrote: >Your measurements look >reasonable and the balun will work just fine assuming a load >close to 50 ohms. Forgot to add that a balun has a lower frequency limit and an upper frequency limit. A balun designed for 30m may not have enough inductance on 80m and may have too much capacitance on 10m. A flat response from 3 to 30 MHz is extremely difficult to achieve (impossible for me :-) 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Wed May 22 18:46:27 1996 From: dteague@csc.com (Guy Teague) Newsgroups: rec.radio.amateur.antenna Subject: Re: Miracle Baby by Comet Date: 21 May 1996 04:02:45 -0400 Message-ID: <4nrtb5$q72@explorer.csc.com> References: <31A0D3F8.3B1@panix.com> Andrew Lin (mmorel@panix.com) wrote: : I have a Kenwood TH-79AD HT and I am looking for a smaller antenna to : replace the original one. I have the Miracle Baby by Comet in mind. : Any suggestions or comments would by appreciated. : Thanks in advance. : Andrew -------- Well ... it's small. -- Cheers 73 de dteague@csc.com "They're out there" K Kesey Guy KG5VT gteague@why.net "Hey don't eat that yellow snow" F Zappa From amsoft@epix.net Wed May 22 18:46:28 1996 From: Jake Brodsky Newsgroups: rec.radio.amateur.antenna Subject: DDRR antenna Date: Mon, 20 May 1996 16:16:24 -0700 Message-ID: <31A0FD48.7BB9@erols.com> References: <4nfi1d$imv@mksrv1.dseg.ti.com> I have seen the DDRR antenna in ARRL literature for years. I've read a lot about WHAT the DDRR is. I haven't seen anything about HOW it works or WHY it is built the way it is. Does anyone have performance data on this beast? What trade-offs does it have? Can one make concentric DDRR antennas for more than one band? If someone doesn't reply soon, my curiousity may get the better of me and I might just have to build one... 73, Jake Brodsky, AB3A Cessna Cardinal N30946 PP-ASEL-IA "Beware of the massive impossible!" From amsoft@epix.net Wed May 22 18:46:29 1996 From: h9502639@hkusua.hku.hk (Mak Wai Han Maria) Newsgroups: rec.radio.amateur.antenna Subject: yagi antenna question Date: 21 May 1996 13:51:37 GMT Message-ID: <4nshp9$gjg@hkusuc.hku.hk> hello eveyone, recently i bought a yagi 5 element 50w 144-146mhz antenna it works fine unforturnately, one of the director(the one closest to the emitter) is broken into 2 pieces. i wonder whether it is possible i just use some super glue to glue them together? is the director need to be conducted?('coz if i use glue it will not conduct) if anyone knows it , please email me!! Thanks! VR2ZPM 5/21/96 From amsoft@epix.net Wed May 22 18:46:30 1996 Newsgroups: rec.radio.amateur.antenna From: Monty Wilson Subject: Re: 80mtr loop (cloud warmer) Message-ID: Date: Wed, 22 May 1996 13:53:05 GMT References: <4ngmqn$1br@news.paonline.com> Siegfried Rambaum wrote: >On 17 May 1996 vjkunesjr@fingerlake3.com wrote: > >> Looking to build a 80mtr loop about 20' off the ground... > >*thinking* ... I just cannot imagine how you would get a sensible loop >for eighty with just 6 meters above the ground.... I can't explain it myself, but my loop is about 20' up on one end and about 30' up on the other side, and I'm getting great reports on 75m from all around Texas. Best of luck with your loop. And by the way, you might consider trying it with just a balun before you hook up your tuner. You might be surprised what it can do without tuning. -- .........Monty. mwilson@flex.net From amsoft@epix.net Wed May 22 18:46:31 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: WB3U/W7EL/W7XC & OTHERS Date: 21 May 1996 16:21:03 GMT Message-ID: <4nsqhf$2u7@itnews.sc.intel.com> References: <4nkqp6$93g@dfw-ixnews3.ix.netcom.com> <4nqu4m$1tm@itnews.sc.intel.com> Cecil Moore wrote: >I have a Ladder-Line Length Selector >remotely switched with 6 4PDT relays that gives me 0-63 ft variable >lengths in increments of one foot. For anyone looking for cheap relays for ladder-line switching, there's a good one in the latest All Electronics catalog (1-800-826-5432). Omron LY2-0-DC24 are DPDT rated at 12 amps at 240vac. Their dielectric strength is rated at 2000vac. They are priced at $2 each Cat# RLY-145. Using 12 of these relays, one can build a 0-63 ft. Ladder-Line Length Selector for $24 (plus ladder-line and 6 remote toggle switches). IMO, these relays will handle 150 watts with no problem. I'm going to try them at 600 watts. Anyone interested in details, email me at kg7bk@primenet.com 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Wed May 22 18:46:32 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: Coax cable shielding - Help please Date: 20 May 1996 12:29:53 -0400 Message-ID: <4nq6m1$q0k@newsbf02.news.aol.com> References: <832518360.13942.0@tfaloon.demon.co.uk> There is magnetic (and electric) field coupling between the shield and the center conductors. It causes the center conductor (if the center is floating without a return path from end to end) have equal in phase voltages with the shield area next to each area of the center conductor. The result is there is no potential difference between the center and the shield, Faraday is happy with that mode. Imagine we are flea sized people crawing in the cable with a RF voltmeter. We could NEVER measure any potential difference with our meter IF the center conductor is unterminated at both ends and we confine our measurements to things INSIDE the cable. We can't measure current or voltage INSIDE the cable with our little meter. If we crawl back on the outside, we will measure exactly the same voltage end to end on the center as on the shield. The coax (twisted or coiled, straight or bent) is indeed a transformer. How the cable behaves depends more on what we do with our outside world connections than how many "shields" we have. 73 Tom From amsoft@epix.net Wed May 22 18:46:33 1996 Newsgroups: rec.radio.amateur.antenna From: Monty Wilson Subject: Re: 11 meter antenna for 10 meters Message-ID: Date: Tue, 21 May 1996 20:32:29 GMT References: <4nsr4t$efk@news.campus.mci.net> brown@auburn.campus.mci.net (Phil Brown) wrote: >Getting back into hamming after several years lapse. Got an old 1/4 >wave CB mobile fiberglass antenna left by my father in law. Anyone >ever use one of these for 10 meters? Lots of folks will tell you that there's no point in making a ground plane for 10m unless it's 5/8 wave. I caution against such a blanket statement. I picked up a CB ground plane cheap when I first got back into radio several years ago. I shortened the radial elements, and removed the loading coil from the driven element and shortened that also. Yes I think it works much better if you have all the radial elements at 1/4 wave. I worked several countries on it, and had loads of fun until I got the Butternut and didn't need the ground plane anymore. I ended up getting the same $20 back out of it that I had originally paid. Back when I was converting CB rigs for 10m and 12m use, I did make some 10m mobile antennas by shortening CB antennas, but always the whip types, never fiberglass. -- .........Monty. mwilson@flex.net From amsoft@epix.net Wed May 22 18:46:34 1996 From: ifindem@fia.net (Mike Obermeier) Newsgroups: rec.radio.amateur.antenna Subject: Re: Foxhunt antenna? Date: Wed, 22 May 1996 05:58:39 GMT Message-ID: <4nua7n$de7@news.htp.net> References: <4nfm8j$7nh@moe.virtual.org> dave@curly.virtual.org (David Black) wrote: >I'm looking for information on how to build foxhunt/T-hunt >handheld antennas for 2m, 440 and 1.2. We have some creative >people here in the Bay Area who've sent along some idears, >and I'm told there is a book by the ARRL available too. >I'd like to build something that's small enough to use while driving >around in a car, while attached to an HT. >Cheers, >Dave KE6AJC If hunting while mobile is your goal you'll get great results with any version of the build it yourself quad. Rig yourself a window mounted mast with the quad on top. Put an attenuator inline to knock down the signal as you get closer to the fox. You could even build multi-band quad ( tuned elements for each band mounted on the same mast). This arrangement could be stored in the trunk when your not using it. If you plan to hunt with your HT prepare yourself for lots if intermod, a helical filter may be in order. "Transmitter Hunting- Radio Direction Simplified" by K0OV/WB6UZZ is a very good reference and has some simple & easy to build antenna projects. Happy Hunting! 73 de KD6SNE Mike Obermeier , ARRL O.O. From amsoft@epix.net Wed May 22 18:46:35 1996 From: tomb@lsid.hp.com (Tom Bruhns) Newsgroups: rec.radio.amateur.antenna Subject: Re: J-pole vs. half wave dipole. Date: 17 May 1996 18:10:08 GMT Message-ID: <4nife0$o2t@hpcvsnz.cv.hp.com> References: <4ng8j6$9m4@news2.inlink.com> Gary V. Deutschmann, Sr. (raiar@inlink.com) wrote: (re: feeding a half-wave vertical against a counterpoise instead of using a J-pole) : Not everyone has room for a counterpoise! It doesn't take much. I did some modeling of feeding a halfwave against minimal radial systems, and found as I recall that even feeding against two, three or four 1/8 wave radials yielded slightly higher gain than a J-pole. Each assumes perfect decoupling from the feedline; the halfwave-over-radials system also assumes lossless impedance matching. One of the most attractive things about the J-pole design is that there are no insulators under tension; the end-fed halfwave-over-radials looks like it's going to need an insulator for the radiator, unless it's perhaps the extension of the center conductor of a quarter wave coaxial stub which is below the radials... that might not be a bad mechanical design to duplicate in a ham's workshop. -- Cheers, Tom tomb@lsid.hp.com From amsoft@epix.net Wed May 22 18:46:36 1996 From: guenter.koellner@oen.siemens.DE (Koellner, Guenter) Newsgroups: rec.radio.amateur.antenna Subject: ? Inductance for 5/8 lambda Date: 15 May 96 19:21:00 GMT Message-ID: <319A2F1A@SmtpGate.Oen1.Oen.Siemens.De> Hello all, I want to build a 5/8 wavelength vertical for 29.250MHz and 14.200MHz as I got a flexible length military antenna. freq wavelength 5/8 29.250 10.256m 6.4m 14.200 21.127m 13.2m Now a question: what is the value of the coil to be added on the base for each system to match it to a 50ohm cable? What is the inductance that is needed to use the 6.4m long antenna on 14.200MHz? That if I do not want to change the length of the antenne while QSY? All would lead to an coil with two taps: - full coil for using the 6.4m long antenna on 20m - next tap to use the 13.2m long antenna as 5/8 on 20m - shortest tap to use the 6.4m long antenna on 10m Do you agree? Can anyone tell me the inductance needed for that? Would you please send a copy of your answer to my personl email? vy 73, Guenter, DL4MEA@DB0KCP.#BAY.DEU.EU (AX.25) dl4mea@amsat.org (Internet) http://www.scn.de/~koellner (WWW) From amsoft@epix.net Wed May 22 18:46:39 1996 From: zliangas@compulink.gr (Zacharias Liangas) Newsgroups: rec.radio.amateur.antenna Subject: questions on loop antenna Date: Tue, 21 May 1996 10:21:49 GMT Distribution: world Message-ID: <4ns4v4$s4q@venus.compulink.gr> Reply-To: zliangas@compulink.gr Friends These last days I have made some experiments with my new loop antenna. It is made in a woodenbut relatively sensitive frame as two points of it have crashed due to use of very long (9 cm) nails ( and of thickness 1.4 mm ) These rods are of 1.5 m X type in which the wire forms a square area rather than the 'classical' rhombic. After this i have put a wire of 1.0 mm hard type for 11 windings on the wooden fame (non standed) which not 100 % formed a coil as some wounds had a tolerance from the exact square of max .6 cm Finally after building it I tested it with and without capacitor for its main use in MW To my surprise the antenna did not show resonace with capacitor but inly without capacitor and at the first 2-3 wounds ! Its results were s not so satisfactory for me as the LOwe HF150 in its ATT position, together with 8 m of RG 59 and clips to the antenna's zero and 2 nd wound showed lower signals than of mine AIWA J150 The nice of the antenna is that it showed good results with its nulls. IN less than 5 degrees the antenna could null out many signals except of the two local stations of 50 kW I do not know why the antenna does not work properly ( ie with the capacitor in paralell ) What do you think I need? To change the wire with a flexible so that geometry can be 99.5% accurate ? Or I need anything other ? I have tried the same project two years ago with a rhombic frame in which the antenna worked properly with the variable capacitor Zakaria Liang! (namanya untuk kawan sahaja!) From amsoft@epix.net Wed May 22 18:46:40 1996 From: boardman@cobra.unm.edu (Bob Boardman) Newsgroups: rec.radio.amateur.antenna Subject: Re: DDRR antenna - reference: RE flagpole antennas Date: 17 May 1996 18:53:56 GMT Message-ID: <4nii04$pq2@lynx.unm.edu> References: <4nfi1d$imv@mksrv1.dseg.ti.com> Reply-To: boardman@cobra.unm.edu In article <4nfi1d$imv@mksrv1.dseg.ti.com>, jafl@msg.ti.com (Jim Flanders) writes: > >When I answered the article - flagpole antenna - many people emailed >me with a question on what is a DDRR antenna. See ARRL Antenna manual >page 6-9.DDRR is short for Directional Discontinuity Ring Radiator. >First described in Electronics, Jan 1993. Later research described in >July 1972 by W2WAM. Imagine the antenna as a small ring insulated just >above a ground plane. Distance above the ground plane is 0.0069 wave >length. Ring diameter is 0.078 wavelength. The coax feedpoint is 0.25 >of distance above ground plane. The far end from the feed is tuned >with a capacitor to ground. The diameter of the conductor is large; i.e >40 meters is 2 inches. I recently built one for 40 meters, and it is >mounted to look like a car carrier on top of my VAN. I had a muffler >shop bend and weld the 2" pipe. It is first mounted on a plywood frame >that is covered with copper screen. A motor (from tanner electronics) >tunes the capacitor. The whole thing is topped with a fibreglass cover, >and the unit is demountable from the van, and can be operated while >placed on my outshed. Size of the plywood is 5' X 11'. >Jim W0oog/5 in Plano on 147.180 > OK, let me work this out. 40m * .078 = 10 ft 3 in diameter, and 40m * .0069 = 10.87 inches. The 10' 3" diameter would make it kind of wide for most vehicles. But the circumference would be 10'3" * 3.14159..., about 32 ft., and you say you used a 5' x 11' plywood base, which would have a "circumference" of 11+11+5+5= 32 ft., so I guess your "ring" is actually a 5' by 11' rectangle, mounted 10.87" above the ground plane? And you say the correct pipe diameter is 2" for 40m - is this calculated as 2"/40m = .0013 wavelength, for other wavelengths? But the big question is, How well does it work compared to other mobil 40m antennas? 73, -Bob =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- = | Bob Boardman, Albuquerque, New Mexico - KC5SFW - ARRL, Upper Rio FM Society | | PGP 2.6.2 public key available | =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- = From amsoft@epix.net Wed May 22 18:46:41 1996 From: chideste@xvnews.unconfigured.domain (Dale Chidester) Newsgroups: rec.radio.amateur.antenna Subject: Re: Plans wanted for an inexpensive 2m antenna Date: 22 May 1996 12:49:20 GMT Message-ID: <4nv2gg$luq@igate2.pt.cyanamid.com> References: <4nth5q$78c@dfw-ixnews8.ix.netcom.com> Reply-To: chideste@xvnews.unconfigured.domain They don't come much cheaper than this one! 73, Dale Plumber's Special 2 meter Vertical Dipole A number of years ago, I built a 2 meter vertical dipole antenna out of plumbi ng parts. This antenna has been mounted on the chimney ever since and withstood all onslaughts from the weather, including 70+ mph winds, record snowfalls, su b zero temperatures, etc. The following shows the basics, although certainly no t to scale: 10' 1" OD PVC Pipe ________ 20" Cu Pipe _________ 20" Cu Pi pe __ __________________________| |______________| |__________ ___| | ______________________________________________________ | COAX ______________________________________________________--------\ | ___________________________ _______________/ _\_________ ___ | |________| |___ ___| |__| | | | | _| |_ | | |_____| PVC Coupling PVC Tee w/ stub End Cap and end cap Two 20" pieces of 1" OD Cu (copper) pipe are cut for the dipole part of the an tenna. I soldered the center conductor of the coax (52 ohm) to the upper piece and the shield to the lower piece. Pay attention to how things are strung together! I used a PVC Tee for the center insulator so I could inspect the coax while assembling and then sealed it with a short stub and end cap. A plain coupling could be used for t he center insulator. End caps, Tee and joints between the Cu pipe and PVC parts were ep oxied for mechanical strength and weather sealing. Two holes were drilled at the bo ttom of the 10' section of PVC pipe and a wire tie used to secure the coax to the pipe for strain relief. The 10' PVC pipe is mounted to the chimney and the coax lays o n the roof. SWR is < 1.3:1 from 144 to 148 MHz. Overall appearance is not too bad, either. From amsoft@epix.net Wed May 22 18:46:43 1996 From: py3crx@sp-gw.py2bjo.ampr.ORG Newsgroups: rec.radio.amateur.antenna Subject: RE: Coaxial Cable Shielding Date: 15 May 96 01:12:41 GMT Message-ID: <38660@SP-gw.ampr.org> Adding some comments to the msg posted by... graham@southlin.demon.co.uk (Graham Seale).... Last year we did a small research concerning some different coaxial cables brands and some different connectors/manufacturers. This rehearse was done using CATV items, so the impedances was 75 ohm. The set-up used was not too much controlled and scientific but for our purpouses was enough. At the CATV industry, as every operator intend to use it's plants at both ways, one concern is the called "ingress" and, at the other side, the law is worried about the "leakeage". The return path at most of the CATV plants falls between 5MHz and 30MHz. This part of the spectrum don't need too much expanation about. The CATV coaxial cable providors have several models and sizes with different braid amount: so we find standard shielding (67% braid coverage), dual shield (claimed 90% or so), tri-shield, quad-shield and hard-line. So we pick 4 samples, different braid amounts, RG59 cables. We used the same "F" connector (same apparent lay-out), one type for each cable diameter. All cables were terminated by a standard 75 ohm load. This cables were placed at one small tower, vertically, lenght abt 25'. The detector was a Tektronix 2714 spectrum analyzer with a built-in pre-amp(20dB gain). The results: The 67% braid cable allow an "ingress" of some locals broadcasts (FM band) that are about 3 to 5 kilometer apart. I don't know the field strenght so... The absolute measured level, worst case, was something about -52dBmV. Some "clinic eye" can realize about an interference at this level, since the minimun signal we use at the TV set (here, at least) is 0dBmV. The other cables didn't allow any measurable signal, even setting the spectrum analyzer to the "worst case" FM signal and trimming the span/div and IF resolution/video filter to an optimal set-up. BUT: when we lose the spectrum side "F" connector abt 1/4 turn, all exist ing signal at the 67% braid cable increase 20...30dB! At the other cables, this signal appear from the noise floor at the same set-up (loose connector). The amount was the same:20 to 30dB. Nothing scientific but we realize that in a practical situation, the connector we were using was not the guilty. The cable, in certain areas. But the assembly care...this item had the heaviest influence. Times-Fiber, Trylogy, Comm-Scope, Belden and other brands normally have some papers concerning the ingress/leak at those cables, normally considering the age and the "number of times that some piece of cable was bent", due to temperature changes. Most of them claim that a 90% braid covereage cable still having a -100...-115dB EMI. Note: at this set-up, the commom mode problem was avoided(we tried) using some ferrite blocks, close to the spectrum analyzer). We still using the same 67% braid covereage cable and only when a specific path become interfered we search the source/spans affected and c change it by a dual shield span. Best regards. Marcus. PY3CRX@SP-GW.PY2BJO.AMPR.ORG - S.aulo - Brasil. From amsoft@epix.net Wed May 22 18:46:45 1996 From: n0nas@hamlink.mn.org (Doug Reed) Newsgroups: rec.radio.amateur.antenna Subject: 2.4 Ghz antennas Message-ID: <832577357.AA06389@hamlink.mn.org> Date: Mon, 20 May 1996 07:21:39 -0100 TG>In article <4mtfa8$loh@crash.microserve.net> TG> jackl@pinetree.microserve.com "WB3U" writes: TG>> Not at all. These antennas are available in omnidirectional TG>> patterns ranging from 11.5 dBi (8-bay) through 16.0 dBi (24-bay). TG>> Physically, they resemble a vertical pipe 5" diameter with a TG>> length ranging from about 3' to 10'. When they are top-mounted on TG>> a tower, visualization of the pattern would produce something akin TG>> to a pancake on a stick. TG>Perhaps you live in a two-dimentional world. The array you described TG>sounds very far from omni-directional to me. TG>Regards, TG> Tony - G3SKR / AA2PM email: tgold@panix.com Hi Tony. It sounds to me like Jack is describing a stacked set of Alford Slot antennas. These are one of the most common forms of omni-directional horizontally polarized antennas made. I'd go so far as to say that most TV stations use this form of antenna, although much larger because of the lower frequency. The Alford Slot antenna doesn't get much press in the common ham handbooks. You will find references to them in the ham TV publications and it was mentioned in the ARRL UHF projects manual as an easy antenna for a UHF beacon system. Of course most ham antennas wouldn't be 16 bays long either. If you want to visualize the Alford slot, think of a section of 4" aluminum vent pipe. This stuff comes from the hardware store with a seam down the side and you clip the edges together to make the pipe. To make an Alford slot you would add metal braces at the top and bottom to hold the seam edges apart about 1/2 inch. The total length of the slot would be 1/2 wave length from short to short. You then feed it in the middle with a 200 ohm (?) balanced feed. The other critical length is the circumference of the tube since it has to be about 1 wavelength at the frequency of operation. If you think of it as a 1 wavelength wire loop stretched to make a 1/2 wave cylinder, you will not be too wrong. For antenna theory, I think the Alford slot was a derivation of the plain old slot antenna where the plane surface was changed to a cylinder. As I said, these antennas are very common in TV applications because the TV station wants a very uniform horizontal pattern. Ham TV repeaters want similar patterns and simple Alford slots made from 1/2" galvanized hardware cloth have been described in ATVQ magazine. The problem with building the antenna is making a good low loss balun. Particularly if you want to stack them for more gain. Another common antenna for ham TV and VHF SSB is the Big Wheel or Little Wheel antennas. They were developed in the early 60's and have almost disappeared from the current ham handbooks. But they had good omni directional patterns and a little gain over a dipole. Fairly easy to build but also pretty large. They consist of three 1 wavelength loops formed into three petals like clover. The three loops are paralleled and matched to coax with a simple stub. Take a look in a 1968 VHF Antenna book. It might be listed in the new ARRL antenna handbook but I don't have one so I don't know. Olde Antenna Labs makes and sells Little Wheels for 432 and up. Hope this helps. 73's. Doug Reed, N0NAS email: n0nas@hamlink.mn.org * SLMR 2.1a * Hello, I am part number |||||||>|||||||| From amsoft@epix.net Wed May 29 23:38:52 1996 From: brown@auburn.campus.mci.net (Phil Brown) Newsgroups: rec.radio.amateur.antenna Subject: 11 meter antenna for 10 meters Date: Tue, 21 May 1996 18:31:25 GMT Message-ID: <4nsr4t$efk@news.campus.mci.net> Reply-To: brown@auburn.campus.mci.net Getting back into hamming after several years lapse. Got an old 1/4 wave CB mobile fiberglass antenna left by my father in law. Anyone ever use one of these for 10 meters? Do I have to have 1/4 wave radials to get it to load up. Thought I would just cut it to length and mount it on a pole on the roof. Thoughts? Thanks. Video Production by MEDIASSOCIATES Like Flowers? Check out our home page at www.tigerweb.com From amsoft@epix.net Wed May 29 23:38:53 1996 From: "Anthony R. Gold" Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: Fri, 24 May 96 14:00:04 GMT Message-ID: <832946404snz@microvst.demon.co.uk> References: <4mq4ka$eeu@news1.demos.su> <4nc11f$pk8@crash.microserve.net> <4ncnfu$7df@panix2.panix.com> <4nd6gd$7ne@crash.microserve.net> <4ne64l$d0f@play.cs.columbia.edu> <4non4l$dq@panix2.panix.com> <31A59CCB.24A5@ozemail.com.au> Reply-To: tgold@microvst.demon.co.uk In article <31A59CCB.24A5@ozemail.com.au> a47186@ozemail.com.au "Steve Richards" writes: > We have two antennas to choose from; a 12.5dbi and a 16dbi. Both have a ve ry > flat much like a "pancake" pattern but they do give the wide coverage. In th is > way the WaveLAN transceivers from a number of buildings can interconnect > providing a radio WAN. Also, these antennas only cost about $A700. Maybe I > should suggest to our supplier to raise his price; US$10000 is unbelievable. Well we now know what to use and a propective user for it in Russia. I'll send him your comments and see what he wants to do. Maybe you could find someone willing to ship one there, if that's the way he wants to go. BTW, I think that the $10,000 rig mentioned before was probably rated at well over 10kW and also perhaps designed to survive 70MPH winds on top of a 75m high tower :-) Regards, -- Tony - G3SKR / AA2PM email: tgold@panix.com tgold@microvst.demon.co.uk packet: g3skr@n0ary.#nocal.ca.usa.na From amsoft@epix.net Wed May 29 23:38:54 1996 From: Steve Richards Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: Fri, 24 May 1996 21:56:03 +1030 Message-ID: <31A59CCB.24A5@ozemail.com.au> References: <4mq4ka$eeu@news1.demos.su> <4nc11f$pk8@crash.microserve.net> <4ncnfu$7df@panix2.panix.com> <4nd6gd$7ne@crash.microserve.net> <4ne64l$d0f@play.cs.columbia.edu> <4non4l$dq@panix2.panix.com> Anthony Gold wrote: > > Jerry B. Altzman (jbaltz@news.cs.columbia.edu) wrote: > > : Indeed, omnidirectional (as I understand it) means omnidirectional on the > : horizon. Jack's respondent is confusing it with >isotropic<. > > Jack's respondent was confusing everyone by answering the question posed > by the first post in this thread. I understand that this was a mistake > and apologise. > > The start of this thread in <4mq4ka$eeu@news1.demos.su> was the question > of "where can I buy an `omnidirectional' [poster's choice of words] > antenna to add to a 2.4 GHz WaveLAN tranceiver in order to boost it's > performance by over 11dB." I said no-way, you'll need amplifiers. But > Jack, who also followed-up that same original posting, gave a quite > different reply. > > Perhaps Jack would email his proposals to the original poster, who is > Shabanov Sergey and give him the good news. > > Regards, > > -- > Tony - G3SKR / AA2PM email: tgold@panix.com > tgold@microvst.demon.co.uk > packet: g3skr@n0ary.#nocal.ca.usa.na This discussion is all very interesting and to some degree shows a knowledge challenge for this area. I've been working with the WaveLAN 2.4GHz product in Australia for the last 3 years, and we have had to develop an antenna that had a wide coverage area (hence not omnidirectional in all planes). This, I think, was what the original posting was all about. We have two antennas to choose from; a 12.5dbi and a 16dbi. Both have a very flat much like a "pancake" pattern but they do give the wide coverage. In this way the WaveLAN transceivers from a number of buildings can interconnect providing a radio WAN. Also, these antennas only cost about $A700. Maybe I should suggest to our supplier to raise his price; US$10000 is unbelievable. Anyway, I hope that I haven't upset the apple cart on this subject, and would gladly welcome what else is said Regards Steve Richards From amsoft@epix.net Wed May 29 23:38:55 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: Fri, 24 May 96 21:53:09 GMT Message-ID: <4o5faj$3an@crash.microserve.net> References: <4mq4ka$eeu@news1.demos.su> <4nc11f$pk8@crash.microserve.net> <4ncnfu$7df@panix2.panix.com> <4nd6gd$7ne@crash.microserve.net> <4ne64l$d0f@play.cs.columbia.edu> <4non4l$dq@panix2.panix.com> <31A59CCB.24A5@ozemail.com.au> <832946404snz@microvst.demon.co.uk> "Anthony R. Gold" wrote: >BTW, I think that the $10,000 rig mentioned before was probably >rated at well over 10kW and also perhaps designed to survive 70MPH >winds on top of a 75m high tower :-) The power rating is approximately 500 watts, with somewhat higher ratings available on special order at additional cost. You're pretty close on the wind survival; many of these are top-mounted on towers at heights of 500-750'. They are used primarily for multi-channel video transmission, often 30 adjacent channels split between two antennas. The power rating is appropriate for this use, even at 100 watts peak output per channel, due to typical losses in the combiners, jumpers and flexible waveguide. The patterns generated by these antennas are exceptionally precise, with a certain amount of null fill and electrical beamtilt being standard features. The latter are required in order to provide coverage to close-in receive sites. I'm very curious about antenna designs claiming similar performance at significantly reduced cost. 73, Jack WB3U From amsoft@epix.net Wed May 29 23:38:55 1996 From: ebuchanan@gnn.com (Ed Buchanan) Newsgroups: rec.radio.amateur.antenna Subject: 6 M antenna revised Date: Sun, 26 May 1996 22:42:24 Message-ID: <4o8uth$o09@news-e2c.gnn.com> Cubex Co has re-tested and re-tuned their 4 element 6 meter antenna. We have re-tuned this antenna to provide 22 db front to back while still retaining over 10 dbd gain, this also impvoved the pattern slightly and makes the antenna shorter (8'X 1-1/2") boom. This is an additional benefit for shipping purposes. "73" Ed KN6CL From amsoft@epix.net Wed May 29 23:38:56 1996 From: aor Newsgroups: rec.radio.amateur.antenna Subject: Re: 6 M Antenna Tested - really???? Date: Wed, 22 May 1996 15:03:18 -0400 Message-ID: <31A364F6.234B@gteais.com> References: <4nop5l$7t6@news-e2c.gnn.com> With all due respect, this sounds a little larger than life. Boom length has the greatest effect on gain for antennas with proper boom illumination (number of elements for a given boom length). Even on short booms, where quads really shine over yagis, a 12dbd (14.1dbi) would require a 1.25-1.50 wavelength boom, about 21-27 feet, and require 5-6 elements. The added gain in a quad comes from the narrowing of the E plane due to self-stacking effects. Without even looking, I suspect that the boom length is only 120" long (40" between spreaders). The gain for this antenna is the same for 6 meters, 2 meters, or 440. About 9dbi or 7dbd for full-size quad elements with .15-.20 wavelength spacings. You would have to double the boom length to get a 3db improvement, taking you back to the 21 foot mark (stated above). What method did they use to measure gain? Two antennas pointed at each other, pattern integration, or E and H plane -3db values? This just reminds me of the 1975 CB radio days, where 4 element antennas had 14dbd gain, and were less than 1/2 wavelength long. It just does not happen. Thanks for the note just the same. Al, NW2M >Ed Buchanan wrote: > > Saturday 5-18-96 Cubex Co. tested their new 4 element 6 meter quad > which is designed to be a sideband antenna. This antenna has over > 12 dbd gain, this is due to the relatively narrow bandwidth > (50.0-51.0 Mhz.) vswr less than 1.7-1 and resonant at 50.3 the > resonant point can be changed slightly (.5 Mhz) with the unique > Cubex adjustable feed point. Front to back was 15-18 db with a > clean pattern and no strange lobes. This antenna will be available > by the first of June, 1996. > "73" Ed KN6CL From amsoft@epix.net Wed May 29 23:38:58 1996 From: ddenter@nortel.ca (Dean Denter) Newsgroups: rec.radio.amateur.antenna Subject: Re: 6 Meter Antenna Recommendation/Question ??? Date: 28 May 1996 13:59:30 GMT Message-ID: <4of0s2$sur@bcarh8ab.bnr.ca> References: <31AAE542.7BA5@staffnet.com> Reply-To: ddenter@magi.com In article <31AAE542.7BA5@staffnet.com>, Bob Lewis writes: >Richard G. Jean Jr. wrote: >> >> Hello Everyone, >> >> I'm looking for recommendations for 6 meter antennas (homebrew) both >> omni directional and directional varieties.. Also, what polarization >> is being used for FM work on 6 meters; I would guess vertical. >> >Vertical polarization for FM and Horizontal for SSB is the standard. >When you get a rig be sure to get SSB too, I think that's the most fun. >A "halo" antenna makes a good horizontal, omni-directional, zero gain >antenna. > haven't seen a 'halo' before, are there plans around for it somewhere? regards, Dean. -- Dean Denter work -> ddenter@nortel.ca VA3CDD play -> ddenter@magi.com [[[[[[[[[[[[[[I speak only for myself]]]]]]]]]]]]]] From amsoft@epix.net Wed May 29 23:38:58 1996 From: jean@pubs15.si.COM (Richard G. Jean Jr.) Newsgroups: rec.radio.amateur.antenna Subject: 6 Meter Antenna Recommendation/Question ??? Date: 23 May 96 18:32:47 GMT Message-ID: Hello Everyone, I'm looking for recommendations for 6 meter antennas (homebrew) both omni directional and directional varieties.. Also, what polarization is being used for FM work on 6 meters; I would guess vertical. I'm going to pick up a 6 meter rig "real" soon (soon as I can find one) and start experiencing some 6 meter activity...... Might try my luck at the Ten Tec 6 meter transverter kit for 2 meters, that way I could mess with it in the mobile without to much fuss. Thanx In Advance !!! Rich - N8PFK From amsoft@epix.net Wed May 29 23:39:00 1996 From: drted@ix.netcom.com(Ted Viens ) Newsgroups: rec.radio.amateur.antenna Subject: Re: Adcock antenna Date: 25 May 1996 04:22:17 GMT Message-ID: <4o61tp$gr7@dfw-ixnews3.ix.netcom.com> References: In sscalsk@atc.ameritel.net (Stan Scalsky) writes: > >Has anyone studied Adcock or Wullenweber antennas? In all the papers I've >managed to find they all mention goniometers but dont really go into much >detail concerning their construction? Are they still made or have they >been replaced by an electronic equivalent? Any pointers? > >-= stan > What a strange bit of serendipity... Monitoring Times had a small article on the WullenWeber a couple of months ago and the June issue had a blurb in the letters section answering these questions. Wullenwebers are massive circular arrays of dipoles. The goniometer is an originally mechanical complex rotary switch which allows you to sweep around the circle of the array. These have by now been replaced by an electronic equivalent. The letter gives the document numbers of several Naval manuals which are claimed to be the best source of info on the Wullenweber... -- Bye... Ted.. Deep in the Heart of the Armpits of Houston, Texas... From amsoft@epix.net Wed May 29 23:39:01 1996 From: Lennart Nilsson Newsgroups: rec.radio.amateur.antenna Subject: Adding 7 MHz to yagi beam Date: 24 May 1996 12:29:18 GMT Message-ID: <4o4a2u$e8d@simba.lejonet.se> I have a Fritzel FBDX-506 six-band yagi covering 10-28 MHz at a 60 ft tower and I want to extend operation to 7 MHz without losing performance on the original bands. What I have in mind is adding lightweight traps at the end of the already trapped 10 MHz-elements (34 ft long) and let stiff copper wires hang down some 10 ft or so from each end. The traps for 10 MHz would have to be made with a high L/C ratio to provide enough loading with such short extensions. The spacing between the 10 MHz dipole and reflector is 13 ft. Has anybody tried a similar idea and what was the result? I am afraid the spacing will be too short to make a decent match to 50 ohms, so the question is whether I shall be content with just modifying the driven element. If so, will it perform better than the quarterwave sloping guywire I am using now? Good advice is welcome. 73 de Lennart, SM5DFF From amsoft@epix.net Wed May 29 23:39:02 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna Subject: Re: Aluminiun Foil for Apartment Ground Plane? Date: 22 May 1996 00:49:23 GMT Message-ID: <4ntoaj$3p2@news.service.uci.edu> References: <4nhnm1$n9h@fcnews.fc.hp.com> In article <4nhnm1$n9h@fcnews.fc.hp.com>, eal says... >Ok, This may indeed be a 'wild hair'. Has anyone tried putting >Aluminum foil UNDER the carpet in an upper story apartment to act as a >local HF ground plane? It looks like I am going to be stuck in apartments >for a few years, and I would like to get a decent antenna in an apartment. >Can anyone recommend a good book on apartment antennas? WA5SWD Be careful to make sure that ANY places that you might have two different sheets of foil touching each other, you must make sure that they are joined solidly. Any movement will cause noise and possible arcing. If you decide to lay some under a carpet, make sure it's under any padding as well. It's not easy to solidly connect foil pieces together. Brian - N6ZAU From amsoft@epix.net Wed May 29 23:39:05 1996 From: "Anthony R. Gold" Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.equipment Subject: Re: Antenna Analysers Date: Thu, 23 May 96 11:06:14 GMT Message-ID: <832849574snz@microvst.demon.co.uk> References: <831505842snz@microvst.demon.co.uk> <832765677snz@microvst.demon.co.uk> <31A3B891.F26@interramp.com> Reply-To: tgold@microvst.demon.co.uk In article <31A3B891.F26@interramp.com> ir002126@interramp.com "Ken Neal" writ es: > My question is a little different-- I have the MFJ-208 for VHF and > the MFJ-247 for HF. Would I be gaining anything (other than a > single unit) by selling these two and buying the MFJ-259? I don't see the 247 in the current catalogue so I can't comment on that, but I note that the 208 shows VSWR but not an antenna's resistance at resonance. If you fancy knowing this, and it may be useful when say fiddling with gamma matches for instance, then the 259 will add that one feature. Unless you can get most of your money back from selling the older instruments or you do this for a living, it may not be worthwhile. Of course, if you've not been naughty, you might try asking Santa :-) Regards, -- Tony - G3SKR / AA2PM email: tgold@panix.com tgold@microvst.demon.co.uk packet: g3skr@n0ary.#nocal.ca.usa.na From amsoft@epix.net Wed May 29 23:39:06 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: Antennas Date: 24 May 1996 06:22:01 -0700 Message-ID: <4o4d5p$m2m@nnrp1.news.primenet.com> References: <31A5240A.37B@ugrad.ug.cs.oz.au> Peter Mackowiak wrote: : What are the basics of antenna design? Hi Peter, IMO one can learn the most about antennas in the shortest time by using an antenna modeling program like EZNEC. It is amazing to be able to perform cut-and-try experiments without leaving the chair at the computer. 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Wed May 29 23:39:07 1996 From: wa5dxp@mail.sstar.com (Jim Overstreet) Newsgroups: rec.radio.amateur.antenna Subject: Re: Anybody tried GAP Eagle DX vertical? Date: Mon, 27 May 1996 22:20:37 GMT Message-ID: <4od9td$1jcj@tetsuo.communique.net> References: <4o2oob$br6@news1.sunbelt.net> <4o4q0d$3saq@info4.rus.uni-stuttgart.de> moritz@ipers1.e-technik.uni-stuttgart.de () wrote: >>.... and know very little about verticals. Anybody have >>any first hand data on this antenna? Thanks. . . . >Gap antennas come with completely false and exaggerated advertizement >claims. They are easily beat by simple wire antennas. (there are test >reports.) It is true that the verticals take up less space though. >73, Moritz DL5UH I second that. I have a friend that bought a Titan, and it is a LOUSY performer, I think his window screen would work better. From amsoft@epix.net Wed May 29 23:39:07 1996 From: Martin Davies Newsgroups: rec.radio.amateur.misc,rec.radio.amateur.antenna Subject: Anyone know how to contact K9AY? Date: Tue, 28 May 96 21:37:13 GMT Message-ID: <833319433snz@amdavies.demon.co.uk> Reply-To: g0hdb@amdavies.demon.co.uk Hi, I'm trying to find a way to contact K9AY, Gary A. Breed, who is (or was in 1994) the Editor and Associate Publisher of the journal "RF Design", the address for which is 6300 S Syracuse Way, Suite 650, Englewood, CO 80111. I'm very interested in Gary's patent-pending design for closely-coupled-resonator antennas which was published in the Nov 1994 issue of the journal and would like to discuss several points with him; however so far I've been unable to find any email or packet radio addresses for him. Does anyone know how to get in touch with him (apart from snail-mail)? By the by, has anyone else tried the c-c-r type of antenna? I would be interested in hearing from anyone who has. 73 es TIA, -- Martin Davies, G0HDB BBS @ GB7GLO.#46.GBR.EU DXCluster > GB7DXC From amsoft@epix.net Wed May 29 23:39:08 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.misc,rec.radio.amateur.antenna Subject: Re: Anyone know how to contact K9AY? Date: Wed, 29 May 96 18:00:45 GMT Message-ID: <4oi3as$j2v@nadine.teleport.com> References: <833319433snz@amdavies.demon.co.uk> In article <833319433snz@amdavies.demon.co.uk>, Martin Davies wrote: >Hi, I'm trying to find a way to contact K9AY, Gary A. Breed, who >is (or was in 1994) the Editor and Associate Publisher of the >journal "RF Design" . . . Gary's no longer with RF Design. He's now with Noble Publishing. You might try their office in Georgia, telephone (404) 908-2320, fax (404) 939-0157. Roy Lewallen, W7EL From amsoft@epix.net Wed May 29 23:39:09 1996 From: jjmartin@ix.netcom.com (James J Martin) Newsgroups: rec.radio.amateur.antenna Subject: Anyone using a TET antenna? Date: Fri, 24 May 1996 12:49:15 GMT Message-ID: <4o4b8i$pa@dfw-ixnews6.ix.netcom.com> I have a model HB33sp (3 ele tri-bander) and over the years the minium SWR point has moved from the middle of the bands to just below the low end. I tried shorting up the elements which worked on 20 meters not on 15 or 10. I would like to hear from anyone also using TET. Jim W8AC From amsoft@epix.net Wed May 29 23:39:10 1996 From: chideste@xvnews.unconfigured.domain (Dale Chidester) Newsgroups: rec.radio.amateur.antenna Subject: Re: Balun for 2M mobile dipole? Date: 22 May 1996 12:47:21 GMT Message-ID: <4nv2cp$luq@igate2.pt.cyanamid.com> References: <4nsnln$tj7@galaxy.cybergate.net> Reply-To: chideste@xvnews.unconfigured.domain The following describes the antenna I use. No balun is required and material costs are a minimum. 73, Dale Plumber's Special 2 meter Vertical Dipole A number of years ago, I built a 2 meter vertical dipole antenna out of plumbi ng parts. This antenna has been mounted on the chimney ever since and withstood all onslaughts from the weather, including 70+ mph winds, record snowfalls, su b zero temperatures, etc. The following shows the basics, although certainly no t to scale: 10' 1" OD PVC Pipe ________ 20" Cu Pipe _________ 20" Cu Pi pe __ __________________________| |______________| |__________ ___| | ______________________________________________________ | COAX ______________________________________________________--------\ | ___________________________ _______________/ _\_________ ___ | |________| |___ ___| |__| | | | | _| |_ | | |_____| PVC Coupling PVC Tee w/ stub End Cap and end cap Two 20" pieces of 1" OD Cu (copper) pipe are cut for the dipole part of the an tenna. I soldered the center conductor of the coax (52 ohm) to the upper piece and the shield to the lower piece. Pay attention to how things are strung together! I used a PVC Tee for the center insulator so I could inspect the coax while assembling and then sealed it with a short stub and end cap. A plain coupling could be used for t he center insulator. End caps, Tee and joints between the Cu pipe and PVC parts were ep oxied for mechanical strength and weather sealing. Two holes were drilled at the bo ttom of the 10' section of PVC pipe and a wire tie used to secure the coax to the pipe for strain relief. The 10' PVC pipe is mounted to the chimney and the coax lays o n the roof. SWR is < 1.3:1 from 144 to 148 MHz. Overall appearance is not too bad, either. From amsoft@epix.net Wed May 29 23:39:11 1996 From: ckollai@cybergate.net (Craig D. Kollai) Newsgroups: rec.radio.amateur.antenna Subject: Balun for 2M mobile dipole? Date: Tue, 21 May 1996 17:53:39 GMT Message-ID: <4nsnln$tj7@galaxy.cybergate.net> Reply-To: Craig@Kollai.com I am planning to buy a 2M mobile transceiver soon as my first rig, and I am thinking about building my own verticly polorized 1/2 wave (or possably full wave) dipole antenna. Once I build it, I intend to connect to my SWR meter and then to my mobile by coax using an so-239 at my antenna and pl-259 connectors on both ends of the coax. My SWR has so-239 on in and out, and I assume my mobile transceiver will as well. I believe I shyould use 50-ohm impedance connections for everything, and plan to design my antenna as such. My question is, am I correct in my assumption that I'll need a balun between teh SWR and Antenna? If so, can anyone recommend a type, where to purchase it, and give me a good guess as to how much it will cost? I want to add a power booster eventqaully, but I'll probably keep this first setup under 200 watts, and would like a balun that can handle such, if I do indeed need one. Lastly, I'm taking my no-code technicain licenseon Saturday morning the 25th, so shortly I'll be adding my call sign to my sig file! -Craig D. Kollai E-mail: Craig@Kollai.com Visit my web page at:: http://www.cybergate.com/~ckollai/homepg1.htm From amsoft@epix.net Wed May 29 23:39:12 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Can I build my own ISOTRON Type Antenna? Date: Wed, 29 May 96 18:18:52 GMT Message-ID: <4oi4cr$j2v@nadine.teleport.com> References: <31AB3CF5.1BB@comm.hq.af.mil> <4oha1l$d44@dfw-ixnews2.ix.netcom.com> In article <4oha1l$d44@dfw-ixnews2.ix.netcom.com>, tmahanna@ix.netcom.com(Thomas R Mahanna) wrote: > >Hi: > I like the ISOTRON Antenna, but it is rather expensive. I would >like to build something similar for my tiny apartment. Where could I >find info on using large area 'plates' for a transmitting antenna. What >would the area of a single plate have to be for, say, 80 meters? To be efficient, a sizeable fraction of a wavelength on a side. You can make the plates smaller and smaller by putting in more and more loading inductance as a coil. This makes the antenna less and less efficient due to unavoidable losses in the coil. By the time you're at the size of the Isotron, the efficiency is very, very low. But you might get a percent or so of efficiency with a reasonable size, and lots of stations can be worked with a watt of radiated power. Roy Lewallen, W7EL From amsoft@epix.net Wed May 29 23:39:13 1996 From: jwc@col.hp.com (John Chapman) Newsgroups: rec.radio.amateur.antenna Subject: Re: DDRR antenna Date: 21 May 1996 21:06:58 GMT Message-ID: <4ntb9i$kpp@nonews.col.hp.com> References: <31A0FD48.7BB9@erols.com> <4nrnj7$ctp@newsbf02.news.aol.com> Sounds similar to M2 SQloop which has horz polarization. John, N0KIC From amsoft@epix.net Wed May 29 23:39:15 1996 From: graham@southlin.demon.co.uk (Graham Seale) Newsgroups: rec.radio.amateur.antenna Subject: Re: DDRR antenna Date: Thu, 23 May 1996 21:20:16 GMT Distribution: world Message-ID: <19960523.212016.56@southlin.demon.co.uk> References: <31A0FD48.7BB9@erols.com> <4nrnj7$ctp@newsbf02.news.aol.com> <4ntb9i$kpp@nonews.col.hp.com> Reply-To: graham@southlin.demon.co.uk In message <4ntb9i$kpp@nonews.col.hp.com> John Chapman wrote: > Sounds similar to M2 SQloop which has horz polarization. > > John, N0KIC > > The DDRR has featured in past issues of the ARRL Handbook, and was also described by W.E. English on pages 28-31 of the December 1971 issue of QST. Peter Dodd G3LDO published a study of the DDRR in "The Antenna Experimenter's Guide. The study was by Robert B. Dome who held 115 patents in the fields of transmitters, receivers and antennas at the time. The main conclusion was that simply by increasing the height of the vertical part of the DDRR structure to 3.5 ft (from 1 ft.) allows a spectacular improvement in efficiency. It changes the radiation resistance from 0.095 ohm to about 1.16 ohms which increases the efficiency from 2.75 percent to 25.8 percent (9.8dB increase in signal strength!). If you do try it, make it taller, reduce the size of the circular part to keep the thing tuneable on the band you want, and use *fat* tubing. Currents get to tens of amps and voltages at the end across the capacitor measure in kilovolts. I hope this helps.. 73's G4WNT -- Graham Seale From amsoft@epix.net Wed May 29 23:39:16 1996 From: pmarkham@sun.lssu.EDU (Peter Markham) Newsgroups: rec.radio.amateur.antenna Subject: design for 1/4 wave z xfmrs for 1/2" catv hardline? Date: 27 May 96 19:04:43 GMT Message-ID: <199605271904.PAA14453@sun.lssu.edu> Looking for a real world design/ideas for 1/4 wave coaxial linetransformers to be able to use catv 1/2" al catv hardline for 144 and 440 mhz, from a 52ohm source to a 52ohm load. So far a friend's attempts have been less than favorable, and I am out of ideas for using the hardware on hand to make the project fly. TIA, Pete/wa4hei . From amsoft@epix.net Wed May 29 23:39:17 1996 From: Dave Hand Newsgroups: rec.radio.amateur.antenna Subject: Re: design for 1/4 wave z xfmrs for 1/2" catv hardline? Date: Tue, 28 May 1996 13:07:18 -0400 Message-ID: <31AB32C6.62FE@microdes.com> References: <199605271904.PAA14453@sun.lssu.edu> <4oevht$pr@nnrp1.news.primenet.com> Cecil Moore wrote: > > Peter Markham wrote: > > : Looking for a real world design/ideas for 1/4 wave coaxial linetransfor mers > : to be able to use catv 1/2" al catv hardline for 144 and 440 mhz, from > : a 52ohm source to a 52ohm load. So far a friend's attempts have been > : less than favorable, and I am out of ideas for using the hardware on > : hand to make the project fly. > > Hi Peter, IMO save your effort. Catv cable is 75 ohms. A 52 ohm > load causes an SWR of 1.44, not enough to worry about on vhf > unless your run is super long in which case you should be using > twin lead. In addition, your load is probably not exactly 52 ohms. > > If you are really determined to achieve an SWR of 1:1, try > variable capacitive impedance dividers at both ends. > > 73, Cecil, KG7BK (W6RCA soon), OOTC Easier yet, just prune the cable length to a multiple of 1/2 wave On 2m the max you would have to cut off is less than 2.6 ft. Dave Wb4hyp From amsoft@epix.net Wed May 29 23:39:18 1996 From: mneverdosky@cycat.com Newsgroups: rec.radio.amateur.antenna Subject: design for 1/4 wave z xfmrs for 1/2" catv hardline? Date: 29 May 1996 13:49:22 GMT Message-ID: <4ohkl2$94c@news.dx.net> References: 199605271904.PAA14453@sun.lssu.edu On 27 May 96 pmarkham said: pm>Looking for a real world design/ideas for 1/4 wave coaxial pm>linetransformers to be able to use catv 1/2" al catv hardline for pm>144 and 440 mhz, from a 52ohm source to a 52ohm load. So far a Why not adjust the load to match the 75ohm hardline. Then try it without any xformer to see what happens. a 1.5:1 SWR is not that bad and you might be suprised at how well it works. Then compare with and matching networks you come up with. have fun Mike Neverdosky N6CHV mneverdosky@cycat.com `[1;33;41mNet-Tamer V 1.03 - Test Drive From amsoft@epix.net Wed May 29 23:39:19 1996 From: anthonys@ix.netcom.com(Anthony Severdia) Newsgroups: rec.radio.amateur.antenna Subject: Re: Do I need to ground attic antennas? Date: 24 May 1996 23:51:24 GMT Message-ID: <4o5i1s$lie@dfw-ixnews10.ix.netcom.com> References: <4o5chc$up@musky.state.wi.us> In <4o5chc$up@musky.state.wi.us> marxj@doa.state.wi.us (John Marx) writes: > >I'm building a home on a rural hilltop. The location alone will make it >lightning prone. Antennas (mine are receive only for FM, TV and Public >Safety bands) will be generally restricted to the attic. Will their >location in the attic reduce their tendency to build a charge and attract >lightning? How important is it to ground them? If it is important, >should I just tap the coax or is a separate grounding wire needed? > >Thanks for any advice. If the location itself is "prone to lightning" as you say, you'd best install an external (separate) lightning accumulator at a high point and well grounded. The antennas in an attic would be least of the problems! -=Tony=- From amsoft@epix.net Wed May 29 23:39:20 1996 From: marxj@doa.state.wi.us (John Marx) Newsgroups: rec.radio.amateur.antenna Subject: Do I need to ground attic antennas? Date: 24 May 1996 22:17:16 GMT Message-ID: <4o5chc$up@musky.state.wi.us> I'm building a home on a rural hilltop. The location alone will make it lightning prone. Antennas (mine are receive only for FM, TV and Public Safety bands) will be generally restricted to the attic. Will their location in the attic reduce their tendency to build a charge and attract lightning? How important is it to ground them? If it is important, should I just tap the coax or is a separate grounding wire needed? Thanks for any advice. From amsoft@epix.net Wed May 29 23:39:21 1996 From: Jonathan Helis Newsgroups: rec.radio.amateur.antenna Subject: Re: Do I need to ground attic antennas? Date: 25 May 1996 21:13:58 GMT Message-ID: <4o7t6m$f99@news.linknet.net> References: <4o5chc$up@musky.state.wi.us> <4o6145$c67@news.tamu.edu> To: marxj@doa.state.wi.us mluther@tamu.edu wrote: >In <4o5chc$up@musky.state.wi.us>, marxj@doa.state.wi.us (John Marx) writes: >>I'm building a home on a rural hilltop. The location alone will make it >>lightning prone. Antennas (mine are receive only for FM, TV and Public >>Safety bands) will be generally restricted to the attic. Will their >>location in the attic reduce their tendency to build a charge and attract >>lightning? How important is it to ground them? If it is important, >>should I just tap the coax or is a separate grounding wire needed? >> >>Thanks for any advice. > >If you are the natural target at a hilltop and are worried about this, put in >a formal lightning arrestor spike setup on the house. Phooyee on worrying >about the indoor receiving antennae. You have a LOT more to worry about >than that! > >Mike W5WQN as a guest at leviathan.tamu.edu (no mail address there) > When I was in school, I had an attic antenna for SWLing for nearly 5 years, and never had a problem. In another house I lived in for about the same amount of time, I had another attic antenna, and again, no problems there. The antenna was just a long wire that was connected to a reciever, and when I got my ham ticket, to a tuner, and I never had a lightening problem inside the house. The only problem I had was when the roof was wet, such as after a rain, the antenna wouldn't always load up on some bands like it normally did. I attributed this to the water making the roof conductive. I don't know if this is accurate, but it's as good a guess as any. Also to be noted is that some roofing materials are conductive, and will interfere with incoming and outgoing signals. In my experience, listening in the rain was difficult anyway, mainly due to electrical interference from lightening, and it's safter to unplug such appliances in electrical storms anyway. These are just my experiences, I didn't live on top of a hill at either house(we don't have many hills in Southern Louisiana), so my advice may not apply. Good luck! 73, Jon Helis, KB5IAV From amsoft@epix.net Wed May 29 23:39:22 1996 From: graham@southlin.demon.co.uk (Graham Seale) Newsgroups: rec.radio.amateur.antenna Subject: Re: Do I need to ground attic antennas? Date: Sat, 25 May 1996 11:17:30 GMT Distribution: world Message-ID: <19960525.111730.30@southlin.demon.co.uk> References: <4o5chc$up@musky.state.wi.us> Reply-To: graham@southlin.demon.co.uk In message <4o5chc$up@musky.state.wi.us> John Marx wrote: > I'm building a home on a rural hilltop. The location alone will make it > lightning prone. Antennas (mine are receive only for FM, TV and Public > Safety bands) will be generally restricted to the attic. Will their > location in the attic reduce their tendency to build a charge and attract > lightning? How important is it to ground them? If it is important, > should I just tap the coax or is a separate grounding wire needed? > Hello John Structures inside an attic will not "attract" lightning. Every single lightning arrestor scheme I have ever seen involved *very* sharp points mounted high outside, connected to a grounded strap, designed to cause a local corona discharge to reduce the potential of the whole structure. Presumably if a strike is imminent, it will go somewhere else. As explained to me, if a strike should happen it will do its damage tracking down the copper strap, lessening the risk of shock and fire in other parts of the building. Although (with cause!) I have had this lifelong lightning paranoia, and I soak up all that is ever discovered about it, I have yet to find really authoritative explanations and advice. The whole recipe for strike avoidance schemes seems to add up to "lightning attractors". A sailing friend once said to me.. "Plant a real *sharp* pole, then stay away from it, and you will be OK; but plant a real *blunt* pole and lean up against it while under an umbrella, then you are temptimg fate!" He also had a low opinion of those who would continue to play golf despite smelling ozone around the little flagpoles. Perhaps this thread will produce some nice credible stuff about lightning. 73's G4WNT -- Graham Seale From amsoft@epix.net Wed May 29 23:39:23 1996 Newsgroups: rec.radio.amateur.antenna From: xx@xx.net (xx) Subject: Dual Band Loop Antenna Reply-To: xx@xx.net Message-ID: Date: Sat, 25 May 1996 17:20:49 GMT I'm looking for information (plans, manufacturer's name, reference book, etc.) about the dual-band, portable, one-wavelength loop antenna shown on the bottom of page 23 in the May, 1996, Nuts & Volts magazine. Please post your replies here. Thanks. From amsoft@epix.net Wed May 29 23:39:24 1996 From: k1jc@empire.net (Joe Ciarcia) Newsgroups: rec.radio.amateur.antenna Subject: Eggbeater Plans Date: Fri, 24 May 1996 16:03:43 -0500 Message-ID: Has anyone ever seen plans to homebrew an antenna similiar to the M2 Eggbeater? Thanks in advance for info. 73, Joe k1jc@empire,net From amsoft@epix.net Wed May 29 23:39:25 1996 From: dougd@lrbcg.com (KC8CGX) Newsgroups: rec.radio.amateur.antenna Subject: EZNEC Software? Date: Fri, 24 May 1996 20:10:54 GMT Message-ID: <4o4qbm$hm4@news.dx.net> Reply-To: dougd@lrbcg.com Where could I purchase this antenna modeling software; approximate price? Thanks, Doug KC8CGX _____________________________________________ North Central Ohio Skywarn Info http://www.amnorth.com/redbone/skywarn.html http://www.amnorth.com/redbone/ham-page.html http://lrbcg.com/dougd From amsoft@epix.net Wed May 29 23:39:26 1996 From: armond@delphi.com Newsgroups: rec.radio.amateur.antenna Subject: Re: Fomula to get SWR from foward and reflected power Date: Thu, 23 May 96 02:15:30 -0500 Message-ID: <5xFsaga.armond@delphi.com> References: <31A10973.1899@wsi.net> <4nrg87$17il@chnews.ch.intel.com> Cecil A. Moore~ writes: >Hi David, I'm surprised you have a wattmeter but not an ARRL >Handbook. . From the IEEE Standard Dictionary: a metal radiating strusture that supports a line current distribution similar to that of a thin straight wire, a half wavelength long, so energized that the current has two nodes, one at each of the far ends." Cheers. From amsoft@epix.net Wed May 29 23:39:26 1996 From: "Anthony R. Gold" Newsgroups: rec.radio.amateur.antenna Subject: Re: Fomula to get SWR from foward and reflected power Date: Thu, 23 May 96 12:46:50 GMT Message-ID: <832855610snz@microvst.demon.co.uk> References: <31A10973.1899@wsi.net> <4nrg87$17il@chnews.ch.intel.com> <5xFsaga.armond@delphi.com> Reply-To: tgold@microvst.demon.co.uk In article <5xFsaga.armond@delphi.com> armond@delphi.com writes: > From the IEEE Standard Dictionary: a metal radiating strusture that supports > a line current distribution similar to that of a thin straight wire, a half > wavelength long, so energized that the current has two nodes, one at each of > the far ends." Then the IEEE have a sloppy definition. Is there any way to energise a metal structure (and of whatever length) such that, if it has only two current nodes, they in any other place than at its [far] ends? Regards, -- Tony - G3SKR / AA2PM email: tgold@panix.com tgold@microvst.demon.co.uk packet: g3skr@n0ary.#nocal.ca.usa.na From amsoft@epix.net Wed May 29 23:39:27 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: Fomula to get SWR from foward and reflected power Date: Fri, 24 May 96 04:52:03 GMT Message-ID: <4o3jfq$e4s@crash.microserve.net> References: <31A10973.1899@wsi.net> <4nrg87$17il@chnews.ch.intel.com> Gary Watts wrote: >I'm surprised that it is not a requirement to have one of those >books. -; > >It really dose not matter what year since IMHO it seems that the >information had been copied for year to year to year Ditto for the MISinformation. ;) 73, Jack WB3U From amsoft@epix.net Wed May 29 23:39:28 1996 From: schmooze@msn.com (Ariel Maiselman) Subject: RE: FS EQUIPOS DE MI ESTACION Date: 27 May 96 22:35:52 -0700 References: <31A9FD43.33D7@cesga.es> Message-ID: <00001fea+000022fd@msn.com> Newsgroups: rec.radio.amateur.antenna Estoy interesado en la anttena, pero no se cuanto es la pts. por Dollar, mas o menos dame la idea cuanto en Dollar. Mandar su respuesta Schmooze@msn.com N3OYK, Gracias From amsoft@epix.net Wed May 29 23:39:29 1996 From: Luis Newsgroups: rec.radio.amateur.antenna Subject: Re: FS EQUIPOS DE MI ESTACION Date: Tue, 28 May 1996 09:41:35 -0700 Message-ID: <31AB2CBF.399F@cesga.es> References: <31A9FD43.33D7@cesga.es> <00001fea+000022fd@msn.com> Ariel Maiselman wrote: > > Estoy interesado en la anttena, pero no se cuanto es la pts. por > Dollar, mas o menos dame la idea cuanto en Dollar. > > Mandar su respuesta Schmooze@msn.com > N3OYK, Gracias.. Aproximadamente 1$ USA = 128 Pts. EB1AKI&EC1ACJ, 73' From amsoft@epix.net Wed May 29 23:39:29 1996 From: jcleland@onramp.net (John cleland) Newsgroups: rec.radio.amateur.antenna Subject: Ground or not grounded Date: 23 May 1996 15:56:12 GMT Distribution: world Message-ID: <4o21qs$d8k@news.onramp.net> Reply-To: jcleland@onramp.net I will soon be finishing the installation of a full wave loop in the trees on some undeveloped land which is visited occasionally for camping and hamming. I have elected to not ground the antenna when not operating. It seems that grounding the antenna would encourage a lightning strike and there isn't a structure to protect. The trees get hit occasionally anyway. Anybody have an y thoughts on this? tnx es 73 John, KC5RYQ From amsoft@epix.net Wed May 29 23:39:30 1996 Newsgroups: rec.radio.amateur.antenna From: n4lq@iglou.com (Steve Ellington) Subject: Re: Ground or not grounded Message-ID: References: <4o21qs$d8k@news.onramp.net> <4o4pcg$pmk@crash.microserve.net> Date: Sat, 25 May 1996 11:05:03 GMT The antenna should be kept grounded at all times. This keeps static voltage from building up near the area of the antenna which is a prelude to lightning striking thus providing excellent protection to your property. If you don't ground it, lighting will be attracted to it and the huge current will find a path to ground through your feed line then through your rig. I recommend a resonant loop fed with a 4:1 balun, current balun preferred, coax to the shack and a good ground on the coax's shield before it enters the shack. -- Steve Ellington N4LQ@IGLOU.COM Louisville, Ky From amsoft@epix.net Wed May 29 23:39:31 1996 From: ve2rre@bbs.ve3fd.ampr.ORG Newsgroups: rec.radio.amateur.antenna Subject: Re: Ham-Ant Digest V96 #301 Date: 28 May 96 05:22:29 GMT Message-ID: <131878@bbs.ve3fd.ampr.org> References: <199605271130.EAA01087@.mail.ucsd.edu> Hi folks! I am looking for info on the MFJ 1796 halfwave multiband antenna. Is it any good or is it a very long dummy load? What about quality and performance? Has anyone compared it to other verticals like the r7? Many tnx and 73 de ve2rre@va3tcp.#eon.on.ca.noam Pierre Beaudin From amsoft@epix.net Wed May 29 23:39:32 1996 From: SteveP@Dartmouth.edu (Steve Peters) Newsgroups: rec.radio.amateur.antenna Subject: Help homebrewing a mobile GPS antenna (quadrifilar?) Date: 28 May 1996 03:12:25 GMT Message-ID: Thanks for taking a few moments to read this, and maybe to respond... I am looking to build a homebrew antenna that will function in the band used to receive GPS signals. Basically, I have an inexpensive GPS receiver that I occasionally use in my vehicle. The vehicle roof and all the other metal provides a darn good shield, so no signals are rx. Commercial units are available (for $150!) that purport to receive these frequencies. I've seen one , and they're small round, and since I didn't own it, I couldn't crack it open to take a look see. So if you have any advice, hints, directions, or references I could look up, I'd be most appreciative. You can either post here, or email direct to SteveP@dartmouth.edu. If I get a good response, I'll compile the information neatly, and repost here, and place it on the WWW. Thanks and 73s Steve Peters N1TYE Lebanon, NH From amsoft@epix.net Wed May 29 23:39:33 1996 From: "Vincent D'Elia, Jr" Newsgroups: rec.radio.amateur.antenna Subject: HF antenna for apartment Date: Tue, 28 May 1996 13:50:45 -0400 Message-ID: <31AB3CF5.1BB@comm.hq.af.mil> I'm thinking of putting my hf on the air and was wondering I should use as a antenna. I'm using aYeasu FT-901 and a MFJ tuner Any suggestions? Vince KC6ISS -- In God we trust, everyone else must show I.D. From amsoft@epix.net Wed May 29 23:39:34 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: HF Mobile Antenna type/placement Date: 24 May 1996 12:51:56 -0400 Message-ID: <4o4pfc$cmj@newsbf02.news.aol.com> References: <4nvemj$ikp@newsbf02.news.aol.com> Subject: VISALIA MOBILE ANTENNA TRIALS From: Jesse Touhey Date: 30 Apr 1996 12:38:13 GMT CONVENTIONAL CALL FS/DB COMMENTS WA6JPR 62.6 Cntr loaded "Bugcatcher",4"coil, 13.5' K6UMB* 62.6 Cntr Loaded "VE7BOC" coil, 13.5' K6IXL 62.3 Cntr Loaded "VE7BOC" coil 13.3' VE7BOC* 62.2 Cntr Loaded "VE7BOC" coil 13.4' K7POF 61.5 Cntr Loaded "Homebrew" coil, 13.5' WB6RVR 61.3 Cntr Loaded "Bugcatcher" coil, 13.4' W6MMA 60.8 BB3 (screwdriver) 64"whip, 12.9' WA6QJX* 60.1 Base Loaded "Homebrew" coil 13.4' WA6SNF 60.1 DK3 (screwdriver) 66"whip, 13' WB6HQK 59.2 Base Loaded 102" CB whip, 13' KA6TAY* 57.7 "High Sierra" (screwdriver) 102"whip, 14' VE7BOC* 57.1 "Hustler High Power system" KA6TAY* 55.3 "High Sierra" 67"whip instead of 102"whip UnConventional WA6QJX* 66.1 4'cap hat+two 8'horiz wires on Van K7POF* 64.4 Large Cap hat, 6"dia coil#10 wire, 13.6' K6ATP 64.1 Large Cap hat, 3"dia coil, 13.6' VE7BOC* 64.1 Cap hat, VE7BOC coil, 13.4' K6SDQ 63.5 Cap hat, Cntr Loaded, 12'11" KG7BK 59.8 Bent over 108"whip on 40m Hamstick * Tested more than one antenna type Conventional: No cap hats,bent over wires etc. Non Conventional: Cap hats, bent over wires, any config other than "conventional". The above trials were held 4/20/96 on 3995kc at the U.S. Towers field range. Distance from equipment was 0.3 miles. Readings is db above zero signal thermal noise of the metering system....73s Jesse (W6KKT) ------------------- Headers -------------------- Path: newsbf01.news.aol.com!newstf01.news.aol.com!news-e2a.gnn.com!howland.resto n.ans.net!news.sprintlink.net!kern.com!news From: Jesse Touhey Newsgroups: rec.radio.amateur.antenna Subject: VISALIA MOBILE ANTENNA TRIALS Date: 30 Apr 1996 12:38:13 GMT Organization: Kern Internet Services Lines: 46 Message-ID: <4m51jl$d8v@ns.kern.com> NNTP-Posting-Host: 204.212.38.199 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 1.22 (Windows; I; 16bit) From amsoft@epix.net Wed May 29 23:39:35 1996 Newsgroups: rec.radio.amateur.antenna From: Bob Lewis Subject: Re: HF Mobile Antenna type/placement Message-ID: <31AAE6AA.67DB@staffnet.com> Date: Tue, 28 May 1996 07:42:34 -0400 References: <4nvemj$ikp@newsbf02.news.aol.com> <4o4pfc$cmj@newsbf02.news.aol.com> W8JI Tom wrote: > > Subject: VISALIA MOBILE ANTENNA TRIALS > From: Jesse Touhey > Date: 30 Apr 1996 12:38:13 GMT > > CONVENTIONAL > > CALL FS/DB COMMENTS > > WA6JPR 62.6 Cntr loaded "Bugcatcher",4"coil, 13.5' > K6UMB* 62.6 Cntr Loaded "VE7BOC" coil, 13.5' > K6IXL 62.3 Cntr Loaded "VE7BOC" coil 13.3' > VE7BOC* 62.2 Cntr Loaded "VE7BOC" coil 13.4' > K7POF 61.5 Cntr Loaded "Homebrew" coil, 13.5' > WB6RVR 61.3 Cntr Loaded "Bugcatcher" coil, 13.4' > W6MMA 60.8 BB3 (screwdriver) 64"whip, 12.9' > WA6QJX* 60.1 Base Loaded "Homebrew" coil 13.4' > WA6SNF 60.1 DK3 (screwdriver) 66"whip, 13' > WB6HQK 59.2 Base Loaded 102" CB whip, 13' > KA6TAY* 57.7 "High Sierra" (screwdriver) 102"whip, 14' > VE7BOC* 57.1 "Hustler High Power system" > KA6TAY* 55.3 "High Sierra" 67"whip instead of 102"whip > > UnConventional > > WA6QJX* 66.1 4'cap hat+two 8'horiz wires on Van > K7POF* 64.4 Large Cap hat, 6"dia coil#10 wire, 13.6' > K6ATP 64.1 Large Cap hat, 3"dia coil, 13.6' > VE7BOC* 64.1 Cap hat, VE7BOC coil, 13.4' > K6SDQ 63.5 Cap hat, Cntr Loaded, 12'11" > KG7BK 59.8 Bent over 108"whip on 40m Hamstick > > * Tested more than one antenna type > > Conventional: No cap hats,bent over wires etc. > > Non Conventional: Cap hats, bent over wires, any config other than > "conventional". > > The above trials were held 4/20/96 on 3995kc at the U.S. Towers field > range. Distance from equipment was 0.3 miles. Readings is db above zero > signal thermal noise of the metering system....73s Jesse (W6KKT) > > > ------------------- Headers -------------------- > Path: > newsbf01.news.aol.com!newstf01.news.aol.com!news-e2a.gnn.com!howland.resto > n.ans.net!news.sprintlink.net!kern.com!news > From: Jesse Touhey > Newsgroups: rec.radio.amateur.antenna > Subject: VISALIA MOBILE ANTENNA TRIALS > Date: 30 Apr 1996 12:38:13 GMT > Organization: Kern Internet Services > Lines: 46 > Message-ID: <4m51jl$d8v@ns.kern.com> > NNTP-Posting-Host: 204.212.38.199 > Mime-Version: 1.0 > Content-Type: text/plain; charset=us-ascii > Content-Transfer-Encoding: 7bit > X-Mailer: Mozilla 1.22 (Windows; I; 16bit) The "shoot-out" tests are true for 75 meters but I would suspect less of a difference in antennas as you go higher in frequency (i.e. 40 and 20 meters). I'd like to see similar tests on other bands. From amsoft@epix.net Wed May 29 23:39:36 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: High SWR problems Date: 23 May 1996 19:56:01 -0700 Message-ID: <4o38g1$3ik@nnrp1.news.primenet.com> References: <4o3353$89@mtinsc01-mgt.ops.worldnet.att.net> Bob Fetter wrote: : I don't have any idea what else to do. Does anyone have any ideas as to : what is wrong? Bob, do you have a ground plane? Without one, you have only half an antenna. Try three or four radials at the base of the antenna. You've probably seen fixed CB ground plane antennas - make it look like that. 73, Cecil, KG7BK (W6RCA soon), OOTC From amsoft@epix.net Wed May 29 23:39:38 1996 From: billn@PEAK.ORG (Bill Nelson) Newsgroups: rec.radio.amateur.antenna Subject: Re: High SWR problems Date: 24 May 1996 04:52:30 GMT Message-ID: <4o3fae$jfg@odo.PEAK.ORG> References: <4o3353$89@mtinsc01-mgt.ops.worldnet.att.net> Bob Fetter (rfetter@worldnet.att.net) wrote: : This will most likely be a simple one for most of you hams out there, but it : has me stumpted. I am using a CB radio for a base station to keep in : touch with our mobil neighborhood watch patrollers. I've got a 102" whip : antenna mounted on the edge of my roof. I'm using RG-58/U coaxial cable, : and I've tried to keep the length of the coax to multiples of 11'10" as best I : could. I've done all this and still I have almost 25% reflected power : showing on my SWR tester. I've tried to tune it by clipping off about 1 - 2" : pieces of the RG-58 at a time and testing it again, but this hasn't helped : any. : I don't have any idea what else to do. Does anyone have any ideas as to : what is wrong? The problem is that you are trying to solve your problem the wrong way. Changing the coax length will NOT affect the VSWR, although it may change the meter reading you get. The only way to actually affect the VSWR is by changing the impedance of the antenna. This is usually done by adjusting the length of the antenna. In your case, the problem is probably due to your using a mobile antenna as a fixed station antenna. Such antennas are NOT designed to operate without a groundplane. You can probably improve the match by providing some ground radials. A better solution would be to get an antenna designed for base use. Bill From amsoft@epix.net Wed May 29 23:39:39 1996 From: marxj@doa.state.wi.us (John Marx) Newsgroups: rec.radio.amateur.antenna Subject: How much does FM polarity shift over 75 miles? Date: 24 May 1996 22:25:44 GMT Message-ID: <4o5d18$up@musky.state.wi.us> I'm interested in improving reception of a distant FM station (about 75 miles away). The station transmits a vertical and horizontal signal of about 15kw. The terrain is generally low rolling hills. I have a six foot FM band antenna and a good receiver with narrow filters (150khz). My questions are: how much does the polarity shift over that distance? If the signal is arriving at an angle, does it result in a significant loss of gain? And, of course, is there anything I can do about it? Any advice appreciated. From amsoft@epix.net Wed May 29 23:39:40 1996 From: hamop@aztec.asu.edu (CHARLES J. MICHAELS) Newsgroups: rec.radio.amateur.antenna Subject: Re: How to connect coax to a quad antenna ??? Date: 22 May 1996 03:38:15 GMT Message-ID: <4nu277$7es@news.asu.edu> Robert G. Strickland rcrgs@regcon.syr.servtech.com said, in response to a queastion about connecting a common feed line to the several driven elemtns of a quad - I have done some modeling of common feed quads using EZNEC, and the general picture is that on 10m, the pattern is semi-useless. Also, for a five band quad, all feeds tied together with one 2:1 balun, there are significant drive impedance mismatches. My conclusion is that each band is best driven separately, with matching adjusted for each band. Robert, Wouldn't this modeling in EZNEC be subject to the requirements shown in the *Crossed dipole* model shown on page 29 of the EZNEC manual? The required minimum length of .02 wavelengths for the wire containing the source would seem to distort the quad from its real length and shape. I have run into this problem before trying to model some of the multiband verticals etx.../ charlie, W7XC -- From amsoft@epix.net Wed May 29 23:39:41 1996 From: Louis Bertrand Newsgroups: rec.radio.amateur.antenna Subject: Re: Larsen glass mount antennas Date: Wed, 22 May 1996 12:59:40 -0400 Message-ID: <31A347FC.4630@tor.comm.mot.com> References: <319d1a33.3929389@news.dxnet.com> <4nqe7c$qge@hpcvsnz.cv.hp.com> <4nqts7$4cqi@news-s01.ny.us.ibm.net> srwhite@ibm.net wrote: > > > I suppose that the 242 may not be as sensitive, and it may also have to do w ith > the fact that he side-mounted the antenna, in other words didn't want to put > it on the center of windshield or back window (due to defroster lines), so h e put it > on a side window on the back of his mini-van... > I was concerned about the effectiveness of glass mount antennas through the shading pattern on my 92 Chev Corsica, so I bought a cheapo Midland glass-mount dual band and did an experiement (naw, that's too easy! It's better to talk it to death...) I applied the antenna to the side window, then to the back window, both times using masking tape to hold everything in place. I then measured the transmit SWR with a good Bird meter. I couldn't measure receive signal strength because I'm using a recycled commercial mobile. To my surprise, the SWR was slightly better on the back windshield (1.4:1 vs. 1.5:1 typically). My conclusions: 1) the shading has no effect; 2) the height of the antenna above the car roof is important (that would explain the performance of the antenna on the side window of your friend's van). 3) alignment of the inside and outside portions is very important. I'll probably ditch the cheapo Midland when Larsen re-issues their KG dual-band antenna later this year. Ciao! --Louis (ve3vhw) -- The usual disclaimers apply. Louis Bertrand, Senior Engineer Motorola Canada LMPS Toronto Design Centre 3900 Victoria Park Avenue SMTP: louisb@comm.mot.com North York, Ontario, Canada From amsoft@epix.net Wed May 29 23:39:42 1996 From: doc@dxnet.com (Anthony O. Cardenas ~ WA6IGJ) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.equipment Subject: Re: Larsen glass mount antennas Date: Sat, 18 May 1996 00:46:28 GMT Message-ID: <319d1a33.3929389@news.dxnet.com> References: <5e7cc$11271c.2ce@NEWS> <4nd2v8$3m2@dfw-ixnews4.ix.netcom.com> Truth is... The 'thru-the-glass' antenna(s) uses two plates as capacity-coupling between the coax and antenna. It will never equal the efficiency of a direct connection to the active element (period). Tony WA6IGJ From amsoft@epix.net Wed May 29 23:39:43 1996 From: Barry Williams Newsgroups: rec.radio.amateur.antenna Subject: re:Log Periodic Antennas Date: Wed, 22 May 1996 19:52:55 -0500 Message-ID: <31A3B6E7.4373@wt.net> I have been using the KLM 10 to 30 Mhz. 7 element LPDA for a couple of years. I had a problem initially with the insulator on the longest element. KLM says that they have changed the materials and that the new insulators are much stronger. I made an aluminum plate to support mine, and it has been O.K. I did notice the reduced front to back ratio when comparing to the TB6EM I had been using. I also noticed that this antenna is very sensitive to metallic objects in the near field. It is on a 67' Rohn 45G fold over. It is guyed at 43', about 30 feet below the antenna. When rotating the antenna the SWR goes up and down. I am checking with the MFJ analyser through 50' of RG213 and about 80' of 9913. I planned to put a vee on this tower but decided to move it to another tower after seeing the SWR variations. 73 Barry From amsoft@epix.net Wed May 29 23:39:44 1996 From: sarosiw (sarosiw) Newsgroups: rec.radio.amateur.antenna Subject: Re: Log Periodic Antennas Date: 24 May 1996 19:11:06 GMT Message-ID: <4o51ka$hsq@niven.ksc.nasa.gov> References: <199605200336.UAA06267@.mail.ucsd.edu> <31A0D9C9.344B@ideanet.doe.state.in.us> In article <31A0D9C9.344B@ideanet.doe.state.in.us>, gianotti@ideanet.doe.state.IN.US says... > >Has anyone ay experience with log antennas for HF -- especially the >Cushcraft Log periodic. >-- >. . . 73 and type to you later > ____. .__ > | | ____ | |__ ____ > | |/ _ \| | \ / \ >/\__| ( <_> ) Y \ | \ >\________|\____/|___| /___| / > \/ \/ > ______________________________________________________________ >| John L. Gianotti KF9GW gianotti@ideanet.doe.state.in.us | >| Dir Computer Services VOICE: (219) 365-8551 x260 | >| Lake Central School Corp. FAX: (219) 365-6414 | >|______________________________________________________________| > Hi John, I built a ten element LPDA, 22 feet long, with ten elements. Best antenna I every had and built. It covers 13.5 to 30 MHz. I used it extensively during the Desert Storm (USAF/MARS). -WS KB4YLY From amsoft@epix.net Wed May 29 23:39:45 1996 From: Richard Kiefer Newsgroups: rec.radio.amateur.antenna Subject: Re: Log Periodic Antennas Date: Sat, 25 May 1996 11:17:04 -0700 Message-ID: <31A74EA0.702B@athena.csdco.com> References: <199605200336.UAA06267@.mail.ucsd.edu> <31A0D9C9.344B@ideanet.doe.state.in.us> John L. Gianotti wrote: > > Has anyone ay experience with log antennas for HF -- especially the > Cushcraft Log periodic. > -- > . . . 73 and type to you later > ____. .__ > | | ____ | |__ ____ > | |/ _ \| | \ / \ > /\__| ( <_> ) Y \ | \ > \________|\____/|___| /___| / > \/ \/ > ______________________________________________________________ > | John L. Gianotti KF9GW gianotti@ideanet.doe.state.in.us | > | Dir Computer Services VOICE: (219) 365-8551 x260 | > | Lake Central School Corp. FAX: (219) 365-6414 | > |______________________________________________________________| Hi John, Yes I have used a 10 element Tennadyne LPDA extensively on 14-30 Mhz. It worked fine for what it is. For example, it is not a high gain antenna, maybe 2-4 dbd depending on band. Only a couple of elements are active on any one band. As best I could tell F/B ratio was about 14-18 db, not to bad. I was ver light weight for a 5 band antenna, about 55 lbs, and very easy to put up. I used a bead balun of about 15 bead sliped over the coax at the feed point, Fairite # 43 material. The only real advantage to a LPDA is wide bandwidth. If you want gain use something else like a quad or yagi. Do not know anything about the Cuchcraft unit but most anything should work ok since the basic concept is very non critical. The main concern is mechanical durability. Good luck. If you put up the Cushcraft let me know the results. Dick, K0DK From amsoft@epix.net Wed May 29 23:39:47 1996 From: dbwillia@uci.edu (Brian Williams) Newsgroups: rec.radio.amateur.antenna Subject: Re: Miracle Baby by Comet Date: 22 May 1996 01:05:46 GMT Message-ID: <4ntp9a$3p2@news.service.uci.edu> References: <31A0D3F8.3B1@panix.com> In article <31A0D3F8.3B1@panix.com>, mmorel@panix.com says... >I have a Kenwood TH-79AD HT and I am looking for a smaller antenna to >replace the original one. I have the Miracle Baby by Comet in mind. >Any suggestions or comments would by appreciated. >Thanks in advance. >Andrew As long as you don't mind performance that seems to be only half that of a regular rubber duck, the Miracle Baby is great. Other than it's small size, there is no advantage of using it. Soooo, if you are so close to the repeaters that you want to use, or are so close you can easily work simplex, it's best stick with as high a gain (actually as low a loss) portable antenna as you can find. Brian N6ZAU From amsoft@epix.net Wed May 29 23:39:47 1996 From: landers@vitek.com (Rod Landers) Newsgroups: rec.radio.amateur.antenna Subject: Re: Miracle Baby by Comet Date: Wed, 22 May 1996 13:38:54 GMT Message-ID: <4nv58o$doj@news.starnet.net> References: <31A0D3F8.3B1@panix.com> Andrew Lin wrote: >I have a Kenwood TH-79AD HT and I am looking for a smaller antenna to >replace the original one. I have the Miracle Baby by Comet in mind. >Any suggestions or comments would by appreciated. >Thanks in advance. >Andrew I heard someone say that if that antenna worked it was a Miracle baby 73, Rod WI0T From amsoft@epix.net Wed May 29 23:39:48 1996 From: Harv Shore Newsgroups: rec.radio.amateur.antenna Subject: Mobile Antenna - Screwdriver vs Tuner and Non resonant antennas Date: 22 May 1996 00:34:22 GMT Message-ID: <4ntnee$hmv@zook.lafn.org> The vehicle is a Dodge Conversion Van with an extended top made of fiberglass. The radio will probably be the ICOM 706. Now for the antenna considering the "screwdiver" class -- brand TBD any ideas? also using an automatic tuner with a fixed length radiator. One friend suggested the antenna could be horizontal and hinged so it could be vertical when we are at the camping grounds. Your opinion Your experience Harv K6EXO From amsoft@epix.net Wed May 29 23:39:49 1996 From: Jack Cronn Newsgroups: rec.radio.amateur.antenna Subject: Re: Mobile Antenna - Screwdriver vs Tuner and Non resonant antennas Date: 23 May 1996 23:58:23 GMT Message-ID: <4o2u2v$md@news.zynet.com> References: <4ntnee$hmv@zook.lafn.org> To: af006@lafn.org I use a 'screwdriver' type antenna and can report nothing but good luck. I do almost 100% of my operating mobile and have received many fine reports. I use a TS50. I've never used any other type, but cannot imagine having any other type, since this has so much convenience. Good luck and hope to meet you on the Air. 73's Jack/N9VLO From amsoft@epix.net Wed May 29 23:39:50 1996 From: wx8l@vtc.tacom.army.mil (Sean McCarthy) Newsgroups: rec.radio.amateur.antenna Subject: Multi-banding a bug catcher? Date: Tue, 28 May 96 05:48:59 GMT Message-ID: <4oe427$t10@vtc.tacom.army.mil> Has anyone ever multi banded a bug catcher by shunting out a portion of the coil? Seems like a good idea for easy band change mobiling. Comments? Sean From amsoft@epix.net Wed May 29 23:39:52 1996 From: Jonathan Helis Newsgroups: rec.radio.amateur.antenna Subject: Re: Need plans for SHORT 40 meter antenna Date: 22 May 1996 01:49:08 GMT Message-ID: <4ntrqk$f9d@news.linknet.net> References: <4nrel3$qvn@wormer.fn.net> To: lebbin@mail.fn.net If your thinking of a commerical antenna, I have used the MFJ-1621 with some success. This is a 54 inch whip that works 40-10 meters. It won't work as well as a full size antenna, but it will radiate. It's only around $80 new, although I've seen them for $50 used at hamfests. You may want to get a copy of the W1FB Antenna Book from the ARRL or another ham books dealer. It has some good ideas for shortened antennas you may want to try. For the ultimate in simplicity(or stupidity, depending on your point of view), you may want to do what I did in my first apartment: I put a square loop on the balcony, set it up so that it could be operated as either a closed or open loop, fed it with twinlead to a homebrew antenna tuner, and tried loading up anywhere I could. This antenna's resonant frequency was around 22 mhz(it will vary depending on the size of the balcony. I have a larger one now, and plan to put one of thes up again soon), and was able to load it up on 40-10. It even loaded up on 80, but I didn't try it there. I did have some luck on 40 CW in the daytime, working nearby states with a fairly good signal. One Friday night, I loaded it up on 20 CW, heard a DL calling CQ, and decided to call him just to see what would happen. He came back to me! I was very surprised. This just goes to show that you can still work HF in a limited area, with a little skill, creativity, and willingness to try anything. Good Luck! 73, Jon Helis, KB5IAV From amsoft@epix.net Wed May 29 23:39:53 1996 From: cmoore@vegas.ch.intel.com (Cecil A. Moore~) Newsgroups: rec.radio.amateur.antenna Subject: Re: Off-centre fed dipole theory question. Date: 25 May 1996 13:52:57 GMT Distribution: world Message-ID: <4o73bp$nrs@chnews.ch.intel.com> References: <4nv5sv$l5u@vkhdsu01.hda.hydro.com> <4nvbbr$7qm@itnews.sc.intel.com> <4o5g50$3an@crash.microserve.net> In article <4o5g50$3an@crash.microserve.net>, WB3U wrote: >I'm very curious about this phenomenon. Why would the feed >location change anything besides the feed impedance? Hi Jack, just a guess. What would happen with a quarter wave vertical with one radial if you lengthened the radiating element and shortened the radial to keep the overall total length constant? My guess is the resonant frequency would change. 73, Cecil, KG7BK, OOTC (not speaking for my employer) From amsoft@epix.net Wed May 29 23:39:53 1996 From: mluther@tamu.edu Newsgroups: rec.radio.amateur.antenna Subject: Re: phased array antenna - ComTek Date: 26 May 1996 02:06:13 GMT Message-ID: <4o8eal$9ta@news.tamu.edu> References: <31A75DD0.2492@ozemail.com.au> <4o744b$quh@nw101.infi.net> Reply-To: mluther@tamu.edu In <4o744b$quh@nw101.infi.net>, Karl Oyster writes: >Paul, > >If you get responses, please post a summary to the list. >I'm close to being "in the market" for an 80M system like >this, but don't know the first thing about how to get it >done. > >Thanks..... > > >Karl, NQ1W > > With four plugs of concrete at more than a cubic yard each and four stalks of Rohn 25G at some 66 feet each, plus the DX Engineering phase box, the phase lines, the control line and feed line to the shack, as well as the radials that both sink the lightning and provide the RF return....... I can tell you it is a LOT of work....... :) Mike W5WQN as a guest at leviathan.tamu.edu (No mail address there) From amsoft@epix.net Wed May 29 23:39:54 1996 From: Jeff Hutchinson Newsgroups: rec.radio.amateur.antenna Subject: Phased B-nut Antennas Date: Sun, 26 May 1996 12:46:15 -0400 Message-ID: <31A88AD7.75DE@digital.net> Does anyone have experience with phasing Butternut vertical antennas? I have two antennas up, spaced 1/4 wave at 14mHz, fed in series with a 3/4 wavelength phasing oine between them. Any suggestions? 73, Jeff W4PBC From amsoft@epix.net Wed May 29 23:39:56 1996 From: jafl@msg.ti.com (Jim Flanders) Newsgroups: rec.radio.amateur.antenna Subject: Re: Phased B-nut Antennas Date: 28 May 1996 20:09:46 GMT Message-ID: <4ofmia$784@ganesh.mc.ti.com> References: <31A88AD7.75DE@digital.net> Jeff: If I read you right. You are feeding the 1/4 wave Verts. with 3/4 wave between them. This = 270 degrees which is effectively -90 degrees. | | A -90 degree phase difference with 1/4 wave feed------| | spacing results in a theoretical 3.1 db gain \ / in one direction, and a null in the oposite dir \ / \/<--3/4 wave You may want to switch the directivity. This can be achieved by feeding in the center with 1/4 wave coax running to the switchbox. Then switch in the 90 degrees to either side for +/- 90 degrees. |<-vert |<-vert | | \ / \ /\<-1/4wave coax /<-1/4 wave coax \ \ \ / \ \ / / ----------------------- feed-------| switch box | One thing I read about, but ------------------------ did not hit home til I did it, is the antennas have to be as identical as possible, otherwise the expected pattern is not achieved. Jim W0oog/5 In article <31A88AD7.75DE@digital.net>, w4pbc@digital.net says... > >Does anyone have experience with phasing Butternut vertical antennas? I >have two antennas up, spaced 1/4 wave at 14mHz, fed in series with a 3/4 >wavelength phasing oine between them. Any suggestions? >73, Jeff W4PBC From amsoft@epix.net Wed May 29 23:39:57 1996 From: Jeff Hutchinson Newsgroups: rec.radio.amateur.antenna Subject: Phased B-nut Verticals Date: Sat, 25 May 1996 23:17:01 -0400 Message-ID: <31A7CD2D.2DDF@digital.net> I have erected two Butternut vertical antennas, spaced 16.5 feet apart (1/4 wave at 20m), and am feeding them in series, with a 3/4 wavelength phasing line between them. Does anyone out there have any experience with using arrays of Butternut antennas? I have some questions. 73 Jeff W4PBC From amsoft@epix.net Wed May 29 23:39:58 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: PLANS FOR DUALBAND JPOLE (Binary file, Graphics) Date: Mon, 27 May 96 16:49:43 GMT Message-ID: <4ocqmf$pk5@crash.microserve.net> References: <4nth5q$78c@dfw-ixnews8.ix.netcom.com> <4o5365$4b3@news1.halcyon.com> <4ob4u4$mcf@chnews.ch.intel.com> xx@xx.net (xx) wrote: >cmoore@vegas.ch.intel.com (Cecil A. Moore~) wrote: >>Hi Randy, are you ignoring the rec.radio.amateur.* guidelines >>or haven't you read them? Binaries are against the guidelines. >Stick it, Cecil, the rest of us appreciated the post---and tell >your Dad to use some of his hard-earned social security >money to buy a 28.8 modem. No, the rest of us did not appreciate the post. This is a discussion group, not a binary group, and you should learn the difference. Besides, with a name like "xx", your opinion isn't worth much. 73, Jack WB3U From amsoft@epix.net Wed May 29 23:39:59 1996 Newsgroups: rec.radio.amateur.antenna From: rooster@iglou.iglou.com (Rooster) Subject: Re: Plans wanted for an i Message-ID: Date: Sun, 26 May 1996 18:11:21 GMT page 18-37, ARRL antenna book, 15th ed. "groundplane antennas for 144, 220, and 440 MHz". these are made from a so-239 connector, brass rod, just your basic inexpensive stuff. Four radials bent down as 45 deg, a vertical 1/4 wave. similar design pg. 20.59, 1995 ARRL handbook for radio amateurs. --- ž OLX 2.1 TD ž The Large Print Givith, and the Small Print Taketh Away -- rooster From amsoft@epix.net Wed May 29 23:39:59 1996 From: Jeff Hutchinson Newsgroups: rec.radio.amateur.antenna Subject: Re: Plans wanted for an inexpensive 2m antenna to go outside. Date: Sat, 25 May 1996 23:10:18 -0400 Message-ID: <31A7CB9A.3B84@digital.net> References: <4nth5q$78c@dfw-ixnews8.ix.netcom.com> Gerald Phillips wrote: > > I am looking for plans/information for an inexpensive 2m antenna that > can be mounted outside. Please email me if you have anything. > Thanks. > > KE4MBD - Travis I am using the rubber ducky that came with my HT. I made up a little extension cable that allows me to put the antenna up a few feet in the room. It's sufficient to hit any of the local repeaters, which is all I wanted to do. Maybe it would work for you, too. 73 Jeff Hutchinson W4PBC From amsoft@epix.net Wed May 29 23:40:00 1996 From: Mark Saunders Newsgroups: rec.radio.amateur.antenna Subject: Re: R7000? Date: Tue, 21 May 1996 23:22:41 -0700 Message-ID: <31A2B2B1.47E@indirect.com> References: <4nhqhe$k2b@ecuador.it.earthlink.net> Roger J. Buffington; AB6WR wrote: > > Has anyone used the new Cushcraft R7000? I'm curious as to how it > performs. I'm also interested in knowing how it handles high power at a > near 100% duty cycle, as for SSTV or digital operations (Amtor/Pactor/RTTY). > > The R-7 was notorious for blowing traps at even modest power levels. (The > R5 does not suffer from this problem, in my experience.) Did the R7000 > cure this problem? Roger, I'm going to buy one with the R80 80m add-on kit next month. My old Hy-Gain AVT18 5 band vertical is 25 years old and in bad condition. I'll fix it up an d use it for Field Day and camping expeditions. I contacted Cushcraft via their home page http://www.cushcraft.com. Send the n an e-mail message from their page, and they will respond to you. I'm impresse d with the rapid responses I received. Regards, Mark Saunders - KJ7BS Glendale, AZ PACKET: KJ7BS@KC7Y.AZ.USA.NOAM INTERNET: tracker@indirect.com From amsoft@epix.net Wed May 29 23:40:01 1996 Newsgroups: rec.radio.amateur.antenna From: psoper@encore.com (Pete Soper) Subject: Re: Radio Shack Tandy Coax any good? Date: Tue, 28 May 1996 13:56:35 GMT Message-ID: References: <31a69ab2.14599252@news.interport.net> <4oaubn$q0g@newsbf02.news.aol.com> red5or7@aol.com (Red5or7) writes: >DOG LEASH! But, some time ago, they started improving their braid >coverage. Now, I think it's right up there with the other brands. Say, By coincidence last night I made a stub filter out of a piece of junk box RS RG8 that I bought around 2/95. The braid coverage looked fine to my eye. It's their prices that drove me to mail order suppliers long ago. Regards, Pete KS4XG From amsoft@epix.net Wed May 29 23:40:02 1996 From: John O'Brien Newsgroups: rec.radio.amateur.antenna Subject: Re: Request comments - Larson mag-mounts Date: Mon, 27 May 1996 03:23:20 -0400 Message-ID: <31A95868.3D19@ici.net> References: <4ndrjl$c6u@excelsior.flash.net> <4nfg6b$11ca@magma.Mines.EDU> Ken Harrison wrote: > > On 16 May 1996, Brian D. Stevens wrote: > > > : I am requesting comments about Larson Antenna mag-mounts. I have > > : experienced with two different NMO-MM mag-mounts that corroded inside an d > > : became disconnected (electrically) from the capacitive coupling surface > > : on the base - resulting in high SWR. Anyone else experience this? > > > > Mine kept falling off at highway speeds and were destroyed before > > they had time to corrode. > > > > B > > I've got a LM-MM and have NEVER had it fall off. It has sustained > continuous speeds of 85 MPH, also. You must be doing something wrong. > > Oh, oh... I know! Is your vehicle steel? greetings! i have a larson mag mount antenna, i've used it for about the last 4 years and have had no problems with it it hasn't fallen off yet, and i tend to travel a bit _too_ fast on the highway s ;) do you leave the antenna on the car at all times? when it's not in use it sits in the trunk, my dad has the same antenna <2m mag mount> and he never takes it off his truck , he's only had one problem with it so far and that was because the coax had sho rted at the feedpoint, i had a similar problem and replaced the coax comments? i think it is a very good antenna, my section of town is a major "hole" and th at lil antenna gets me out 73's John N1NJI ps.. i homebrew all my other antennas, i have a j-pole made out of copper pipe and a 1/4 groundplane made out of coat hangers antone know of any good, and cheap programs for the ibm/pc platform... design, testing, etc... tnx! ------------------------------------------------------------------------------ Radioactive cats have 18 half-lives. From amsoft@epix.net Wed May 29 23:40:03 1996 From: Bert - ns4w Newsgroups: rec.radio.amateur.antenna Subject: Rohn 25 limits Date: Tue, 28 May 1996 17:32:38 -0700 Message-ID: <31AB9B26.701C@tdsnet.com> Reply-To: ns4w@tdsnet.com Hi All, Assume a Rohn 25G tower, concreted base section, 3'X4'X3' hole. What windload ratings at 20' & at 30' ? Thanks, Bert - NS4W ns4w@tdsnet.com From amsoft@epix.net Wed May 29 23:40:04 1996 Newsgroups: rec.radio.amateur.antenna From: dts@senie.com (Daniel Senie) Subject: Re: RS telescoping masts? Message-ID: <4ob995$j8n@peanut.senie.com> References: <4n54i5$ki0@omnifest.uwm.edu> <4nv32g$fhs@newsbf02.news.aol.com> <4o1loa$o13@nnrp1.news.primenet.com> <31A59F24.41C67EA6@plhp002.comm.mot.com> Date: Mon, 27 May 1996 03:58:29 GMT In article <31A59F24.41C67EA6@plhp002.comm.mot.com>, Bruce Burke wrote: >n7tcf@primenet.com wrote: >> >> The Home Depot product is basically the same thing as the RS. Same >> cautions apply. Be sure to guy properly, don't walk it up, don't put much u p there. >> >> Jim N7TCF >> >> In <4nv32g$fhs@newsbf02.news.aol.com>, daddydavid@aol.com (DaddyDavid) writ es: >> >They look good , but I've not used them. A cheaper alternative at Home >> >Depot is a three section 15' tublar steel telescoping bird feeder pole. >> >I've had one up in 40+ winds with 7 lbs of wooden bird house at the top. >> >Very easy to Telescope. >> >de N9PVF > >Fifteen feet is a little much to transport. Most vans and Chevy Blazer style >vehicles will handle 10 feet. That's what roof racks were invented for! We regularly have 18 foot long kayaks on the roofs of our vehicles. (Yeah, it does look a little odd). Dan N1JEB From amsoft@epix.net Wed May 29 23:40:05 1996 From: cliffd@zetnet.co.uk (Cliff Davies) Newsgroups: rec.radio.amateur.antenna Subject: Re: T2FD Dimensions?? Date: Mon, 27 May 1996 12:07:11 +0100 Message-ID: <4oc69m$uqa@roch.zetnet.co.uk> References: <4obete$3to@sjx-ixn5.ix.netcom.com> In message <4obete$3to@sjx-ixn5.ix.netcom.com> eskaggs1@ix.netcom.com (Eric Skaggs) writes: > Anybody out their have dimensions for a 80-10 mtr. T2FD antenna > utilizing 50 ohm terminating resistor???? > Eric KI6EO Hi Eric, For 3.6 and up it's 91' 1" (27.76m) and a spacing of 2' 8"ins, Thats each side AND includes the spacing, I've only ever seen reference to using anything between a 300-600 ohm terminating resistor,... but I could be wrong:) Email me if you need more info. Cliff GI3HNM From amsoft@epix.net Wed May 29 23:40:06 1996 From: mcewenjv@songs.sce.COM (JAMES MCEWEN) Newsgroups: rec.radio.amateur.antenna Subject: test,do not bother to read Date: 23 May 96 16:38:05 GMT Message-ID: <9604238328.AA832865976@ccgateout.songs.sce.com> told U so! KA6TPR From amsoft@epix.net Wed May 29 23:40:08 1996 From: alexevon@abraxis.com (Alex Evonosky) Newsgroups: rec.radio.amateur.antenna Subject: Re: Tribanders?? Which to Buy??? Date: Wed, 22 May 1996 22:58:24 GMT Message-ID: <4o079r$gvo@clark.zippo.com> References: <4nne5t$g6s@useneta1.news.prodigy.com> <31A21E39.5AD2@prodigy.com> BJR wrote: >Peter Bealo wrote: >> >> Hi, I'm interested in a new tribander in the <=$600 range. Any opinions >> out there about which to consider?? >> >> I am replacing an old Telrex that did a great job for me, but alas is no >> more (didn't survive the last move we made). >> >> The new antenna will be up ~30 feet. >> >> How about the Mosley stuff?? Some friends like Cushcraft. WHat do you >> think? >> >> The antenna must be able to withstand tough New Hampshire winters. >> >> Peter WB2MJG Plaistow NH >Peter, >Take a look at Force 12, most notably the C3. I put one together >yesterday in about 2 hours. No hose clamps - antenna elements are >riveted together. You can actually put the thing together without a tape >measure as all element holes are pre-aligned at the factory. Like the >KLMs no traps either. As to performance, my C3 is still on the ground but >I have used others in the past and they work as advertised. >You can e-mail me if you would like to discuss in more detail, however >my Prodigy E-mail connection is intermittent so don't know if I can >receive any mail or not. >Bob R. (VE6KRR) You can try the KLM KT-34XA...Excellent performer and can be found priced around the 600 mark.. Excellent results and windload is abt 9sq ft. Alex-kb4lbx From amsoft@epix.net Mon Jun 03 17:22:57 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: PLANS FOR DUALBAND JPOLE (Binary file, Graphics) Date: 27 May 1996 14:27:01 -0700 Message-ID: <4od6n5$9kf@nnrp1.news.primenet.com> References: <4nth5q$78c@dfw-ixnews8.ix.netcom.com> <4o5365$4b3@news1.halcyon.com> <4ob4u4$mcf@chnews.ch.intel.com> xx wrote: : Stick it, Cecil, the rest of us appreciated the post---and tell : your Dad to use some of his hard-earned social security : money to buy a 28.8 modem. Too yeller-livered cowardly to post under your name, eh? Are you advocating violation of the r.r.a.* guidelines? If you're a ham, your're one of the rotten apples of amateur radio. Did you pass the Morse code test? :-) I gave my dad a 14.4 modem. The telephone lines in Madisonville, TX are so bad that the modem always reverts to 1200 baud. You can appreciate a binary posting just as well if it is posted where it belongs - on a binary group. And thousands of dollars of r.r.a.* bandwidth need not be wasted by posting it here against the guidelines. Can't bring myself to say 73 - doubt if you know the meaning anyway. Cecil, KG7BK From amsoft@epix.net Mon Jun 03 17:22:58 1996 Newsgroups: rec.radio.amateur.antenna From: xx@xx.net (xx) Subject: Re: PLANS FOR DUALBAND JPOLE (Binary file, Graphics) Reply-To: xx@xx.net Message-ID: References: <4nth5q$78c@dfw-ixnews8.ix.netcom.com> <4o5365$4b3@news1.halcyon.com> <4ob4u4$mcf@chnews.ch.intel.com> Date: Mon, 27 May 1996 15:17:28 GMT cmoore@vegas.ch.intel.com (Cecil A. Moore~) wrote: >In article <4o5365$4b3@news1.halcyon.com>, >Randy Seacat wrote: >> >>Here are the plans for a dualband copper catus (Jpole) that I put together >>in a graphical format. Wish we had a rec.radio.amateur.binaries or >>something. >Hi Randy, are you ignoring the rec.radio.amateur.* guidelines >or haven't you read them? Binaries are against the guidelines. >Simply post the binary to a binary group and do a descriptive >posting here telling everyone where you put it. >My dad doesn't appreciate having to spend his social security >to download your binary files at 1200 baud over long distance. >73, Cecil, KG7BK, OOTC (not speaking for my employer) Stick it, Cecil, the rest of us appreciated the post---and tell your Dad to use some of his hard-earned social security money to buy a 28.8 modem. From amsoft@epix.net Mon Jun 03 17:22:59 1996 From: mwalkdba@ezl.com (Mark Walker (N9HCI)) Newsgroups: rec.radio.amateur.antenna Subject: Re: 80mtr loop (cloud warmer) Date: Mon, 27 May 1996 17:13:31 GMT Message-ID: <4ocnhl$1eh@ns1.ccinet.net> References: <4nnmnv$bn7@news.asu.edu> Hello, all! You may have seen my earlier posts here, where I related my amazing DX success with a low horizontal loop. It's a killer antenna and if you want to know just why it's so great on 20-10, check out May 1990 QST on page 28. Complete with E and H-plane diagrams. I have been collecting info from other loop owners for several years, and at this point, I would have no other antenna connected to my shack. The debates on this subject, like any other in ham radio, could go on forever. All I can humbly suggest is that anyone with a little space try it out. There aren't many tricks involved, but I've already helped several guys with some info from earlier postings here and am glad to help again. Of course, I'd rather have monbanders at 90 feet, but short of that, I'll never own any other antenna. By the way, I rarely use it on 75 or 160, but the big bonus there is that its an extremely quiet antenna. 73, good DX to everyone, Mark N9HCI mwalkdba@ezl.com From amsoft@epix.net Mon Jun 03 17:23:00 1996 From: Jake Brodsky Newsgroups: rec.radio.amateur.antenna Subject: Re: DDRR antenna Date: Tue, 28 May 1996 12:32:17 -0700 Message-ID: <31AB54C1.6EEB@erols.com> References: <31A0FD48.7BB9@erols.com> <4nrnj7$ctp@newsbf02.news.aol.com> So in summary, a DDRR would be a very short vertical antenna with one heck of a capacity hat *real* close to the ground. Or is it something more like a loaded loop running real close to the ground? I'm also a bit curious as to why the emphasis on large pipe? Is it skin effect and high currents they need to overcome? 73, Jake Brodsky, AB3A "Beware of the massive impossible!" From amsoft@epix.net Mon Jun 03 17:23:01 1996 From: cooperjim@aol.com (CooperJim) Newsgroups: rec.radio.amateur.antenna Subject: Re: Need plans for SHORT 40 meter antenna Date: 28 May 1996 12:34:55 -0400 Message-ID: <4of9vf$dj5@newsbf02.news.aol.com> References: <4odo7p$6rr@nnrp1.news.primenet.com> Reply-To: cooperjim@aol.com (CooperJim) The ARRL Antennea Book has designs for small transmitting loop antenneas that cover 40 meters. These work well but have narrow bandwidth. From amsoft@epix.net Mon Jun 03 17:23:01 1996 From: gearloos@pacbell.net (Gyro) Newsgroups: rec.radio.amateur.antenna Subject: Butternut HF6v High noise Date: 28 May 1996 20:51:32 GMT Message-ID: <4ofp0k$a7m@news.snfc21.pacbell.net> I was given(so I thought) a hf6v 80 - 10 with the 160 coil added on it. Now I have been asked to buy it. It is about 3 years old and seems to work ok. Anyone know what this should be worth? Also...I have about 7-9 s units of noise most of the time. The antenna is up 30 ft. which is about 6 ft(base) above the roof. The mast goes down to a 200 ft long chainlink fence post and is attached there . What can I do about this. The noise is not much affected by band. I am in a commercial complex. Could the power be filtered differently? thanks in advance. 73..............KE6OTT From amsoft@epix.net Mon Jun 03 17:23:02 1996 From: NJC@WARWICK.NET (Nick J Chiarchiaro, AET / N2QXF) Newsgroups: rec.radio.amateur.antenna Subject: Re: HF antenna opinion Date: Tue, 28 May 1996 22:36:05 GMT Message-ID: <4ofvhu$62q@news1.warwick.net> References: <4ocnq6$n70@news1.warwick.net> <4oe8ni$edf@crash.microserve.net> jackl@pinetree.microserve.com (WB3U) wrote: > NJC@WARWICK.NET (Nick J Chiarchiaro, AET / N2QXF) wrote: >>I have aquestion to the group. I have recently 'liberated' a >>point on my roof for another antenna. >> >>I am trying to decide which avenue to pursue. A vertical or >>rotatable dipole. >> >>Currently I am using a set of paralell dipole 80-10 at 35'. Reults >>are not bad and I realize at 80-40 it is relatively omnidirectional. >> >>The mounting location is at 50' above ground on a rather sturdy >>mount. (it held a 13b2 2m beam and 2 phased 4 el 2m beams) >> >>I was thinking of getting the 40/20/15/10 world ranger dipole from >>cushcraft. While it would have 0db gain it would still have some >>directivity on the upper bands. However, the radiation angle I >>think would be rather high. >> >>Then I started thinking of a 80-10 vertical. The radiation angels >>all seem to be around 16dg. Being the height is kinda high I could >>probably get away with no to many radials or if I get a model that >>doesn't 'reuire' any. >Efficiency of multi-band verticals is usually much less than >full-size dipoles on 80 & 40 meters, due in part to the shortened >elements and losses in the multiband feed system. Also, verticals >are noisier than horizontal wires, so the choice may depend on >where you live. The problem of noise will obviously be worse in a >metropolitan area. >The difference in radiation angle that you mentioned is also a >factor. Generally speaking, the dipole will be superior at >distances of 1,000 miles and less, while the vertical will often >provide improved DX performance. >Despite it's somewhat reduced efficiency, I would probably add >the vertical. That way, you could switch in whichever type of >antenna is most effective for the prevailing conditions. I >wouldn't spend additional money for a vertical capable of 80M >operation though. The efficiency is likely to be very poor on >that band and it may not even perform as well as the dipole >you're already using. >73, >Jack WB3U Tnx jack, Most who have responded kinda like full size dipoles the best, as long as there is room for them. So with that in mind i would probably stay with the dipoles, and 'save' the money Nick From amsoft@epix.net Mon Jun 03 17:23:04 1996 From: anthonys@ix.netcom.com(Anthony Severdia) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew Subject: Re: need help with wire dipole Date: 29 May 1996 00:58:36 GMT Message-ID: <4og7fs$pjd@dfw-ixnews7.ix.netcom.com> References: In charlie@netdepot.com (Charlie Fortner) writes: > >I'm planning to put up a 250 ft (approx. full wave 80m) wire dipole and >feed it with ladder line for use as a multiband antenna. If the legs are >more than 90 degrees apart in the horizontal and veritical planes, will >the radiation pattern be substantially different that if it was 180 >degrees in each plane? Any other suggestions appreciated. Thanks. > >73 de KF4GJQ (Charlie Fortner) Charlie, you don't say how high at the apex! This makes a considerable difference too. Yes, the radiation pattern will be different at the fundamental freq and very different at the harmonics but if you put up such "long one" don't worry about it ...just use it and make your observations! Good luck -=Tony=- From amsoft@epix.net Mon Jun 03 17:23:05 1996 From: John O'Brien Newsgroups: rec.radio.amateur.antenna Subject: Re: Plans Needed for 2-Meter J-Pole (Plumbers Delight) Date: Wed, 29 May 1996 01:33:33 -0400 Message-ID: <31ABE1AD.2B93@ici.net> References: <31A8AD61.2BF@ix.netcom.com> zafod@ix.netcom.com wrote: > > Does anyone know where, _on the Net,_ I can find plans for a "Plumbers Delig ht" 2-meter > J-Pole? (The type I'm thinking about is made from 1/2" copper pipe.) > > [This is for a beginner---he's in a geographic location/situation that makes textbook > access difficult. It would be my intent to zip it up and e-mail it to him.. .he has > plenty of 1/2 copper pipe, tho!] > > 73 > > KJ6EF check out: ftp://ftp.funet.fi/pub/dx/txt/antennas/jpole.txt it has the plans for the "plumber's dream" i did a search using lycos, http://www.lycos.com/ searched for jpole and the first entry i found was this text file, there is another file in that directory for a jpole made out of 300ohm tv wire..... i use the copper pipe jpole, and my radio club has had some discussion over plans for the antenna, we've got two sets of plans, each one sugesting a different feed point, i have mine fed at one point, a friend of mine has his fed the opposite way, and both work fine as far as we can tell, i get a good match all across the 2m band....it's a big step up from the 1/4 wave groundplane i built out of coathangers :) -john... N1NJI --------------------------------------------------------------- disclaimer: signature file brought to you by the makers of prep-h "cause one asshole just isn't enough" -loading signature file- you've just been violated by: John W. O'Brien III poet, actor, lover,electrical engineering student, computer god, and all around genius. has been quoted as saying: -> "Quos amor verus tenuit tenebit" ->"Radioactive cats have 18 half-lives." ->"love is like dogshit, you don't 'fall in love' you step in it." From amsoft@epix.net Mon Jun 03 17:23:06 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: Multi-banding a bug catcher? Date: 29 May 1996 02:20:44 -0400 Message-ID: <4ogqbs$gg0@newsbf02.news.aol.com> References: <4ofres$euv@vtc.tacom.army.mil> In article <4ofres$euv@vtc.tacom.army.mil>, wx8l@vtc.tacom.army.mil (Sean McCarthy) writes: >Hi Cecil, > >I was thinking of a passive approach using parellel capacitance to shunt a >portion of the coil. Swan made an antenna like this called a 742 or 370-19. > >They used 2 varible and 2 fixed caps to shunt 2 portions of the coil, giving >75/40/20 operation. Their coil was 2" diameter, 10 tpi, 85 turns total. >A fixed 100pf 5kv in series with a 125pf varible was connected from the >10th turn to the 28th turn, and again from the 33rd to the 44th. > >Sean Hi Sean, That is a disasterious thing to do to a loading coil. It radically increases the circulating currents, makes the antenna become narrow-banded, and lowers the efficiency all in one swoop! That's one of the reasons a capacitance hat should never be mounted close to a loading coil. 73 Tom From amsoft@epix.net Mon Jun 03 17:23:07 1996 From: kb8jvh@nextek.net Newsgroups: rec.radio.amateur.antenna,rec.radio.homebrew Subject: Re: Need Source for Aluminum Tubing Date: Wed, 29 May 1996 03:50:28 GMT Message-ID: <4oghpq$9gn@news2.ee.net> References: <4nqb6l$3hl@newsroom.HITC.COM> <4o7h6s$r8@news.dca.net> Give Texas Towers a call Gerald can fix you up with all the aluminum you need. Tony pthompso@taratec.com (peter J thompson) wrote: >csmith1@ccgate.hac.com (Chris Smith, NR3O) wrote: >>Am looking for local (MD/DC area) or mail order source for aluminum >>tubing for antenna project. 1/2, 3/8 and 1/4" diameters in 5-6 ft >>lengths. >>73 and tnx de Chris >>Please respond here and to csmith1@ccgate.hac.com >Chris, > I think you can get Al. Tubing in the sizes you mentioned in most of >the larger >hardware stores (Eg.Hechinger here in DE). I'm pretty sure I saw some >while I >was looking >for some 2in diameter which, so far I have been unable to locate! I >need >about 12 to 15in >to replace the base of my Cushcraft R5 which got damaged. Please let >me know >if you find >out about any good sources. >73, Pete N3EVL From amsoft@epix.net Mon Jun 03 17:23:08 1996 Newsgroups: rec.radio.amateur.antenna Subject: Re: hacking a 2M 5/8 magmount installation thru hole in apartment Message-ID: <1996May29.042929.7479@grian.cps.altadena.ca.us> From: morris@grian.cps.altadena.ca.us (Mike Morris) Date: Wed, 29 May 1996 04:29:29 GMT References: <4nfi1d$imv@mksrv1.dseg.ti.com> <31A0FD48.7BB9@erols.com> n4jvp@ix.netcom.com (N4JVP) writes: >On Mon, 27 May 1996 01:55:46 GMT, wa2ise@netcom.com (Robert Casey) >wrote: >-snip- >>before. And the landlord won't see it, and probably wont see the 1/4 >>inch hole in the ceiling after I move out. A little spackle will >>take care of it anyway. >forget the spackle, try a dab of plain old dab of white toothpaste. >Toothpaste will not shrink either and its a lot cheaper than a small >can of spackle.... Or stick a Moly bolt in the hole and hang a $9.95 battery oeraated smoke detector on the Moly. -- Mike Morris morris@grian.cps.altadena.ca.us #include I have others, but this works the best. Looking for CDA-banned material? Try the bible: Genesis 19:30-38, or Ezeikel 23:20. From amsoft@epix.net Mon Jun 03 17:23:09 1996 From: kferguson@aquilagroup.com (Kevin AstirCS "1U" KO0B) Newsgroups: rec.radio.amateur.antenna Subject: Re: Phased B-nut Antennas Date: Wed, 29 May 1996 10:20:23 -0700 (PDT) Message-ID: <4ohted$o6b@blixen.aquilagroup.com> References: <31A88AD7.75DE@digital.net> >Does anyone have experience with phasing Butternut vertical antennas? I >have two antennas up, spaced 1/4 wave at 14mHz, fed in series with a 3/4 >wavelength phasing oine between them. Any suggestions? I envy the fact that you have the real estate to do such experimenting! I had a roof mounted Butternut bander up , 4 radials on 80 & 40, 6 on 20 & 15, and 12 on 10...untill it tangled with tornado associated winds & neighbors airborn tool shed (no exageration!) and expired. It was one excellent radiator in A/B comparison with dipoles. One big suggestion: Beg, buy, borrow or steal a copy of ARRL Antenna Book, and read everything on feeding of phased verticle arrays written by Roy Lewallen (W7EL). Then read it again and again untill it all sinks in. My Antenna book is a couple of years old..hopefully the material on phased arrays is still in the current book. Roy? The Readers Digest version: The Phase and magnitude of the radiation from a verticle is determined chiefly by the _current_ flowing at it's feedpoint. Unless it presents a 50ohm resistive load, (or whatever Z0 might be for the line you use) , then the current supplied to the radiator will _not_ be phase shifted by the electrical length of the line, and may be either greater or less than current in other element. The other radiator in the phased array disturbs the feedpoint impedance of the antenna, so that even an antenna which is perfectly matched by it's lonesome will not be so when used in the array. So the phase and magnitude of the currents is not determined soly by the lengths of the feedlines. (though it still matters) Connecting two identicle verticles with 3/4 wave line between them will _not_ result in quadrature current flowing in the elements. Roy Lewallan may not have been the first to figure this out, but he has done a magnificent job of presenting the material, and has come up with a very slick, simple way to deal with the problem. Compared to radials, mechanical considerations, etc, doing it right doesn't require a lot more effort, and very little expense. The data presented by W7EL indicate that this doesn't have much impact on forward gain, but has a _huge_ effect on F/B. With two verticles, you are looking at only ~3dB forward gain anyway, so the real motivation should be F/B improvement. W7EL does suggest that you stick to simple 1/4 wave radiators. Hinting that "shorteners" (Like the Butternut resonators) may cause some odd effects when used in an array. I would still be tempted to try to make it work, however. As 1/4 wave spacing will only be on one band, you could make up a "monoband Butternut" (1/2 wave on twenty, or 1/4 wave on 15 for example) and save the expense of a second "real" Butternut. Do the final tweaking with a test source ~ 1/2 mile off the back, and try to get a null. The ~1/4 wave (on 20) 75 Ohm section (I assume Butternut still doing this) will throw a wrench in W7EL's current forcing method. So it would be best to eliminate it and find some other way to get SWR down on 20. -73-, and If anything I said reduces you willingness to experiment, then by all means ignore me! ko0b I From amsoft@epix.net Mon Jun 03 17:23:11 1996 From: warasanz@correu.gencat.es (Lluis Arasanz i Nonell) Newsgroups: rec.radio.amateur.antenna Subject: Re: PLANS FOR DUALBAND JPOLE (Binary file, Graphics) Date: Wed, 29 May 1996 11:04:17 GMT Message-ID: <31ac2ee9.100427931@noticias.ibernet.es> References: <4nth5q$78c@dfw-ixnews8.ix.netcom.com> <4o5365$4b3@news1.halcyon.com> Reply-To: warasanz@correu.gencat.es ki7zd@coho.halcyon.com (Randy Seacat) wrote: +--->travisp@ix.netcom.com (Gerald Phillips) writes: +---> +--->>I am looking for plans/information for an inexpensive 2m antenna that +--->>can be mounted outside. Please email me if you have anything. +--->>Thanks. +---> +--->>KE4MBD - Travis +---> +---> +---> +--->Here are the plans for a dualband copper catus (Jpole) that I put together +--->in a graphical format. Wish we had a rec.radio.amateur.binaries or +--->something. +---> Which bands 2mts / 70 cmts ? thanks. From amsoft@epix.net Mon Jun 03 17:23:11 1996 From: adam@tbsa.com.au (Adam Maurer) Newsgroups: rec.radio.amateur.antenna Subject: 6MX eggbeater Date: 29 May 1996 11:54:11 GMT Message-ID: <4ohdt3$qvt@news.tbsa.com.au> Hi, Adam in Melbourne here. Has anyone had any experience with eggbeaters, particularly on 6MX? What's the performance like? Any there any good articles you could make me aware of? Please email me and let me know. 73, Adam VK3ALM From amsoft@epix.net Mon Jun 03 17:23:13 1996 From: jafl@msg.ti.com (Jim Flanders) Newsgroups: rec.radio.amateur.antenna Subject: Re: DDRR antenna Date: 29 May 1996 17:04:33 GMT Message-ID: <4oi031$8j0@ganesh.mc.ti.com> References: <4of131$5eg@fcnews.fc.hp.com> <4ofimj$1jv@newsbf02.news.aol.com> Tom: My next question is: What will give me more signal on 40 from my Van? Will it be a DDRR mounted on the roof - or will it be a Texas Bug Catcher? You don't have to answer the question. I am going to try to find someone In the N. TX or S. OK area that will loan me a TBC for a weekend test after I modify the DDRR for 2 ft spacing. Jim W0oog/5 in Plano TX on 147.180 & subvets net on 14.243 @ 1130 CST. In article <4ofimj$1jv@newsbf02.news.aol.com>, w8jitom@aol.com says... > >In article <4of131$5eg@fcnews.fc.hp.com>, Edward Lawrence writes: > >>Since I was the person who posted the "idiotic" comment, I will expand on >>the reason I said that. The first article I ever saw referred to a CB >>version, >>and the 'hula hoop' antenna was described as a DRR, or 'Discontinuity >Ring >>Radiator'. The name came from the originators idea that the thing >radiated >>because each little change in direction caused a 'discontinuity" ie: >>impeadance >>change, thus leaking RF at this supposed 'discontinuity". This is >hogwash! >>Granted, I did not read the original papers on this antenna, but I think >the >>name says it all. Thus I say "idiotic" theory! > >Many mystical antennas (like the DDRR) are based on incorrect or pie in >the sky theories. > >Correctly described, the DRR or DDRR is a short top loaded vertical. EM >radiation occurs primarily from the short vertical section. There is no >"magic" or unique theory involved. The DDRR doesn't behave at all like a >slot antenna, it behaves much more like a VERY short vertical section >inverted L with a folded flat-top. > >If you want to see a similar re-invention of the same inefficient design, >look at the ARRL Antenna Compendium. There is a "Magnetic Folded Loop" >that uses the same principle, rolled in with some wild theory about the >element being a low loss "magnetic radiator". It goes on to describe an >even wilder theory, how the folded element raises the radiation resistance >and efficiency. > >"Designers" bend the area that doesn't radiate a bit differently, and >claim a wild new magical high efficiency design. > >In reality, all of these antennas are very short low efficiency top loaded >verticals (like a **very short** inverted L), or small arrays of the same >low efficiency antenna designs. > >"Idiotic" may sound a bit harsh, but it is a correct description of >feebleminded or foolish theories surrounding these antennas. If you take >notes and look closely at their behavior, they follow all the rules of any >short radiator. > >73 Tom From amsoft@epix.net Mon Jun 03 17:23:13 1996 Newsgroups: rec.radio.amateur.antenna From: lloyd korb Subject: Dual Band Yagi Design Message-ID: <1996May29.192021.16947@picker.com> Date: Wed, 29 May 1996 19:20:21 GMT Has anyone tried to model any dual band yagi's with YA,YO, AO or YAGIMAX? I would like to model a 6 & 2 meter yagi on the same boom. Lloyd K8DIO korb@xraymkt.picker.com From amsoft@epix.net Mon Jun 03 17:23:14 1996 From: kamst39+@pitt.edu (Keith A Monahan) Newsgroups: rec.radio.amateur.antenna Subject: Antennas Date: 29 May 1996 20:19:04 GMT Message-ID: <4oibfo$l89@usenet.srv.cis.pitt.edu> I'm still rather new to the radio field, so you'll have to forgive any questions that many of you will consider basic. What is an ideal antenna for each band? ie, what is the relationship between frequency and length of antenna? Can an antenna be too long or too short? Whenever someone talks about a 1/4 wave or 5/8 wave antenna what do they mean? Which is better? And why? Is there some sort of basic principle that states, antennas will be more efficient if they are some even multiple of the wavelength? All size considerations excluded, would the BEST possible antenna be one that is the same length as the wave of the frequency? Thanks in advance. Keith From amsoft@epix.net Mon Jun 03 17:23:15 1996 From: Darrel Emerson <74010.2230@compuserve.com> Newsgroups: rec.radio.amateur.antenna Subject: Re: design for 1/4 wave z xfmrs for 1/2" catv hardline? Date: Wed, 29 May 1996 22:46:17 -0700 Message-ID: <31AD3629.A84@compuserve.com> References: <199605271904.PAA14453@sun.lssu.edu> To: Peter Markham Peter, here is an alternative to the quarter-wave matching section, to match 75-ohm to 50-ohm coax. Since you're matching 75 ohm cable to 50 ohm cable, you probably have spare lengths of each. From the 50-ohm cable, connect one twelth-wavelength (electrically) of 75-ohm cable. Then connect a one-twelth-wavelength of 50-ohm cable between the free end of this section of 75-ohm, and the final 75-ohm cable you're matching. e.g. ----------------++++----++++++++++++++++++ 50 ohm 75 50 75 ohm This avoids trying to find a length of 61-ohm coax to make a quarter-wave matching transformer. The bandwidth of this transformer is very reasonable (at least comparable to the true quarter-wave matching transformer.) The only disadvantage is that there's one more connection than in a simple quarter-wave transformer. If you plot this out on a Smith chart, allowing for the 1:5 SWR in each component of the matching transformer, it's fairly easy to see how this transformer works. (Strictly speaking it's not EXACTLY one-twelth sections, but it's close enough and easier to remember. You can use the Smith chart to show how close it comes.) Good luck, cheers, Darrel Emerson, aa7fv. From amsoft@epix.net Mon Jun 03 17:23:16 1996 From: carrjj@aol.com (CARRJJ) Newsgroups: rec.radio.amateur.antenna Subject: miniNEC software Date: 30 May 1996 02:02:28 -0400 Message-ID: <4ojdlk$gqn@newsbf02.news.aol.com> Reply-To: carrjj@aol.com (CARRJJ) Does anyone know where to download the BASIC for miniNEC (not EZNEC and ELNEC which are proprietary). Reply to carrjj@aol.com From amsoft@epix.net Mon Jun 03 17:23:17 1996 From: lstolz@freenet.columbus.oh.us (Lynn Stolz) Newsgroups: rec.radio.amateur.antenna Subject: Anybody using Fritzel Windoms? Date: 30 May 1996 08:35:21 -0400 Message-ID: <4ok4m9$145@acme.freenet.columbus.oh.us> I'd like to hear from anyone using the Fritzel OCF antenna(s). ...wondering how well you like or hate it. do you have it installed in the suggested inverted-vee configuration or not, etc... I am thinking of replacing my old separate 40 and 80 meter dipoles with one. Thanks, Lynn N8AJ -- Lynn Stolz N8AJ --lstolz@freenet.columbus.oh.us From amsoft@epix.net Mon Jun 03 17:23:18 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: DDRR antenna Date: 30 May 1996 10:10:59 -0400 Message-ID: <4oka9j$pb4@newsbf02.news.aol.com> References: <4oi031$8j0@ganesh.mc.ti.com> In article <4oi031$8j0@ganesh.mc.ti.com>, jafl@msg.ti.com (Jim Flanders) writes: >Tom: > My next question is: What will give me more signal on 40 from my >Van? Will it be a DDRR mounted on the roof - or will it be a Texas >Bug Catcher? You don't have to answer the question. I am going to >try to find someone In the N. TX or S. OK area that will loan me a TBC >for a weekend test after I modify the DDRR for 2 ft spacing. >Jim W0oog/5 in Plano TX on 147.180 & subvets net on 14.243 @ 1130 CST. > > That's an easy question to answer. It will be a DDRR. Remember this and you won't go wrong.... Antennas generate the EM (Electromagnetic) radiation effect from accelerating electrons. Other effects disappear rapidly as distance is increased. The only way that effect is canceled is when two separate groups of electrons are accelerated opposite directions. In the DDRR, the electrons in the short vertical section have no opposing electrons to cancel their effects. The short vertical section radiates freely. The horizontal section, being folded and near a groundplane, induces current in the groundplane that opposes the radiation effect of the electrons in the ring. That's why the ring area radiates poorly, and the antenna has little very horizontally polarized radiation. There is one tiny area where the useful radiation occurs in this antenna, the vertical conductor. That is why, if you look at the previous post about radiation resistance and efficiency, you will see the radiation efficiency increased by the square of the height increase. I'm afraid there is no magic involved in this antenna (as with any antenna). In this case, its radiation resistance is virtually the same as any conductor the same height carrying linear current over it's length. If you replaced it with short top hat loaded vertical with proper design, the vertical would win! The vertical would have less distributed loss in the hat than the DDRR has in the ring. 73 Tom From amsoft@epix.net Mon Jun 03 17:23:19 1996 From: w8jitom@aol.com (W8JI Tom) Newsgroups: rec.radio.amateur.antenna Subject: Re: Multi-banding a bug catcher? Date: 30 May 1996 10:11:47 -0400 Message-ID: <4okab3$pbi@newsbf02.news.aol.com> References: <4oipmv$86i@vtc.tacom.army.mil> In article <4oipmv$86i@vtc.tacom.army.mil>, wx8l@vtc.tacom.army.mil (Sean McCarthy) writes: > >Never thought about this. What do you recomend for 75-10 mobile opeation? >Do you reccomend skipping the cap hat or how far up from the coil would you >put it? >I have a GLA systems bug-catcher, 5' mast, #66 coil (3"x10", 6 T.P.I.) >Without a hat, I would need 8' of whip to resonate, I have a 12" hat. > >Lots-o-questions... > >Sean Hi Sean, An antenna radiates because of the electrons moving in the element. Those electrons stop moving (the current terminates) in a capacitance, the smaller the capacitance the move voltage appears at that point. If the hat has a lot of capacitance compared to the whip, most of the current flows into the hat. If the hat is below the top of the whip, the area of the whip above the hat is just waving in the breeze with no (or greatly reduced) current. If the hat is large (capacitance wise) you might as well snip the whip off above the hat and throw it away. The next time you see a long whip and a huge hat a few feet above the coil, remember this. Grin and remind yourself the whip must be a status symbol because it sure isn't radiating. The position of the hat is probably more important than the position or size of the coil in most cases. Remember three rules: The current entering and leaving the coil is essentially equal at both ends. The taper of the current above the coil is effected mainly by where the terminating capacitance is. The radiation resistance and efficiency are greatly increased when the current is as large as possible over the maximum length possible. Doubling the current area is equivilent to reducing losses four times! That's why I concentrate on linear current over the entire radiator, rather than a huge coil. 73 Tom From amsoft@epix.net Mon Jun 03 17:23:20 1996 From: Roland S Geter Sr Newsgroups: rec.radio.amateur.antenna Subject: Re: FS EQUIPOS DE MI ESTACION Date: 30 May 1996 11:09:49 GMT Message-ID: <4ojvlt$l5t@news1.goodnet.com> References: <31A9FD43.33D7@cesga.es> To: otero@cesga.es Si todavia tienes el KENWOOD TS=450SAT favor de explicar su precio in dolares U.S. Gracias Rolando From amsoft@epix.net Mon Jun 03 17:23:21 1996 From: Roland S Geter Sr Newsgroups: rec.radio.amateur.antenna Subject: Re: FS EQUIPOS DE MI ESTACION Date: 30 May 1996 11:11:32 GMT Message-ID: <4ojvp4$l5t@news1.goodnet.com> References: <31A9FD43.33D7@cesga.es> To: otero@cesga.es Si todavia tienes el KENWOOD TS-450SAT favor de explicar el precio en dolares U.S. Gracias Rolando From amsoft@epix.net Mon Jun 03 17:23:21 1996 From: Roland S Geter Sr Newsgroups: rec.radio.amateur.antenna Subject: Re: FS EQUIPOS DE MI ESTACION Date: 30 May 1996 11:12:44 GMT Message-ID: <4ojvrc$l5t@news1.goodnet.com> References: <31A9FD43.33D7@cesga.es> To: otero@cesga.es Si todavia tienes el KENWOOD TS-450SAT favor de explicar el precio en dolares U.S. Gracias Rolando From amsoft@epix.net Mon Jun 03 17:23:22 1996 From: Roland S Geter Sr Newsgroups: rec.radio.amateur.antenna Subject: Re: FS EQUIPOS DE MI ESTACION Date: 30 May 1996 11:12:46 GMT Message-ID: <4ojvre$mfc@news1.goodnet.com> References: <31A9FD43.33D7@cesga.es> To: otero@cesga.es Si todavia tienes el KENWOOD TS-450SAT favor de explicar el precio en dolares U.S. Gracias Rolando From amsoft@epix.net Mon Jun 03 17:23:23 1996 From: Roland S Geter Sr Newsgroups: rec.radio.amateur.antenna Subject: Re: FS EQUIPOS DE MI ESTACION Date: 30 May 1996 11:13:52 GMT Message-ID: <4ojvtg$mfe@news1.goodnet.com> References: <31A9FD43.33D7@cesga.es> To: otero@cesga.es Si todavia tienes el KENWOOD TS-450SAT favor de explicar el precio en dolares U.S. Gracias Rolando From amsoft@epix.net Mon Jun 03 17:23:24 1996 From: mpfb8@central.susx.ac.uk (Peter Reed) Newsgroups: rec.radio.amateur.antenna Subject: Reduced size HF QUAD - correction Date: 30 May 1996 11:58:38 GMT Message-ID: <4ok2he$3a6@infa.central.susx.ac.uk> In my posting the length of the bamboo spreaders should read 8 feet not 6. = = Peter G4BVH P.L.Reed@sussex.ac.uk From amsoft@epix.net Mon Jun 03 17:23:25 1996 From: sander@aud.alcatel.com (dick sander) Newsgroups: rec.radio.amateur.antenna Subject: 160m added to a 18HT Hytower Date: 30 May 1996 17:11:02 GMT Message-ID: <4okkr6$5gm@news01.aud.alcatel.com> Reply-To: sander@aud.alcatel.com I just picked up a used 40m trap for my Hygain 18HT hytower to operate 160 meters at a flea market. I don't have any instructions with it. Before I have to deal with HyGain, I'd thought I try the newsgroup. I attached the uncovered end (opposed to the black plastic cover on the other end) to the very top of my hytower. I attached 105ft of wire to the covered end and strung it up. The vswr on 75m stayed about the same. On 40m the vswr dip dropped down to 6.8 MHz. I tweaked the 105ft wire to 1.85 MHz vswr dip. I then removed the 90" 40m stinger from the top of the hytower. The vswr dip on 75m went up to nearly 4 MHz. On 40m the vswr dip moved up to 6.95 MHz. I retweaked the 105ft wire to 1.88 MHz. My questions are: Could I have the 40m trap backwards? Should I have not needed to remove the 40M stinger? Should the trap mount slightly below the top the tower? Could the trap be bad? Does anyone have anything to add that might help me with the installation of the trap? Thanks and 73, Dick Sander - K5QY From amsoft@epix.net Mon Jun 03 17:23:26 1996 From: username@shore.net (Your Name) Newsgroups: rec.radio.amateur.antenna Subject: 1/2 wave dipole vs. full wave question. Date: 30 May 1996 18:35:41 GMT Message-ID: <4okppt$ms2@shore.shore.net> Reply-To: cborg@tiac.net. Hello antenna folks: I have a question. Perhaps someone could share a little insight with me. The other day I set up my old CB radio (no flames please) which I hadn't playe d with since my highschool days - 10 years ago. I consulted my ARRL handbook, (I'm interested in HAM stuff) got about $3.50 worth of #10 guage copper wire, some RG-8 coax, constructed a 1/2 wave dipole antenna, and tuned it up using a VSWR meter (readings around 1.4:1 ). It seems to work pretty well from my house next to the ocean - last night I contacted a station in Newfoundland from my place in Massachusetts (!). The antenna is strung horizontally from the highest point on my house (about 28 feet) to a nearby tree. Rope is tied to the copper wire, and is what is tied to the house and the tree. (I figured that unless it rains , it should be a good enough insulator) Anyway, my question: All other things being equal, if I constructed my homebrew antenna version 2.0 as a full wavelength, instead of a 1/2, would there be any real measurable results? Would the impedence of the antenna change, necessitating some sort of a matching network? Just curious. Any guidance would be appreciated. If you would E-mail me your reply, I'd probably get it sooner. Thanks a bunch, and 73's Chris. From amsoft@epix.net Mon Jun 03 17:23:27 1996 Newsgroups: rec.radio.amateur.antenna From: cluett@mv.mv.com (Jim Cluett) Subject: Re: Anybody using Fritzel Windoms? Message-ID: Date: Thu, 30 May 1996 18:58:43 GMT References: <4ok4m9$145@acme.freenet.columbus.oh.us> In article <4ok4m9$145@acme.freenet.columbus.oh.us>, Lynn Stolz wrote: > >I'd like to hear from anyone using the Fritzel OCF antenna(s). >...wondering how well you like or hate it. do you have it installed >in the suggested inverted-vee configuration or not, etc... > >I am thinking of replacing my old separate 40 and 80 meter dipoles with one. > >Thanks, > >Lynn N8AJ >-- >Lynn Stolz N8AJ --lstolz@freenet.columbus.oh.us I'm using the FD-4. This is a fine antenna. I'm using it with a yaesu FT-900AT. I use it on all bands from 80 to 10. Working great DX on all bands, very good reports. I have no hesitation in recommending it. Very fine quality hardware. Be careful about having a good ground. Mine is about 45 feet in the air, straight across (not inverted V). hope this helps N1TOD From amsoft@epix.net Mon Jun 03 17:23:28 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: phased array antenna - ComTek Date: Thu, 30 May 96 19:11:16 GMT Message-ID: <4ol04l$oec@crash.microserve.net> References: <31A75DD0.2492@ozemail.com.au> <4o744b$quh@nw101.infi.net> <4o8eal$9ta@news.tamu.edu> <4o8r48$gu1@dfw-ixnews2.ix.netcom.com> <4oe0vi$nb8@news.tamu.edu> mluther@tamu.edu wrote: > There are worse forms of insanity. > > Try a full sized 3 element rotary array on 80 at 195 feet! I've seen that antenna! About 50 miles west of Houston, I think. ;) 73, Jack WB3U From amsoft@epix.net Mon Jun 03 17:23:29 1996 From: w7el@teleport.com (Roy Lewallen) Newsgroups: rec.radio.amateur.antenna Subject: Re: Antenna wire diameter important? Date: Thu, 30 May 96 19:42:30 GMT Message-ID: <4oktln$4v0@nadine.teleport.com> References: <4ok0h7$8lc_001@leeds.ac.uk> Keywords: wire In article <4ok0h7$8lc_001@leeds.ac.uk>, CBS5LD@leeds.ac.uk (L. DE BRUIJN) wrote: >Is the width of the wire used for an antenna important? I'm using 26SWG >(0.45mm) diameter wire at the moment for a long wire antenna. I can see how >it might make a difference at high power (increased temperature dissipation >problems) but does it matter for receive? TIA > > 73 de > Laurens The wire diameter affects the resonant frequency, bandwidth (the range of frequencies over which a specified maximum SWR is obtained), and loss (therefore efficiency). None of these is important for receiving at frequencies below VHF. Roy Lewallen, W7EL From amsoft@epix.net Mon Jun 03 17:23:29 1996 From: Chuck Bland Newsgroups: rec.radio.amateur.homebrew,rec.radio.amateur.antenna Subject: Just enough to hang my. . .antenna Date: 30 May 1996 19:54:16 GMT Message-ID: <4okud8$9st@mtinsc01-mgt.ops.worldnet.att.net> Greetings, I'm in the process of hanging a dipole antenna, and I will be using ropes at the ends to suspend it. What type of rope should I use? I live in Sacramento, CA. Hot, dry summers, rainy, windy winters. No snow. 73's Chuck - n6dbt From amsoft@epix.net Mon Jun 03 17:23:30 1996 From: Steve Kennedy Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.equipment Subject: Re: Antenna Analysers Date: 30 May 1996 20:28:56 GMT Message-ID: <4ol0e8$5mu@nadine.teleport.com> References: <831505842snz@microvst.demon.co.uk> <832765677snz@microvst.demon.co.uk> To: tgold@microvst.demon.co.uk I bought one of the MFJ 259 units too. I don't know how I muddled through ant ennas and resonant circuits before I got this unit. It is great! The peace of mind and surity it brings to my dealings with resonance and imped ance approaches a religious experience! Steve WB7PSD From amsoft@epix.net Mon Jun 03 17:23:31 1996 From: mjappine@news.hit.fi (Mika Antero Jäppinen) Newsgroups: rec.radio.amateur.antenna Subject: Multiband-ant Help! Date: 30 May 1996 21:51:42 GMT Message-ID: <4ol59e$4mt@perjantai.hit.fi> Hello, I am looking for instructions for multiband antenna for receiving purposes from low-vhf to approx 1GHz. I have allready familiar with discone but was wondering does there exist similar type wide-band coverage antenna? Ofcourse there is log-periodig-yagi's but I am looking for more likely something omnidirectional GP type. Ofcourse it obvious that these multiband-antennas are always compromises but if you might have some hints to replace my VHF (2m) gp to someting else which is hooked-up to R7100 let me know! Antero Jappinen Email mjappine@maanantai.hit.fi Packet OH2LJH@OH2BAR.FIN.EU From amsoft@epix.net Mon Jun 03 17:23:32 1996 From: anthonys@ix.netcom.com(Anthony Severdia) Newsgroups: rec.radio.amateur.homebrew,rec.radio.amateur.antenna Subject: Re: Just enough to hang my. . .antenna Date: 30 May 1996 22:22:04 GMT Message-ID: <4ol72c$662@dfw-ixnews9.ix.netcom.com> References: <4okud8$9st@mtinsc01-mgt.ops.worldnet.att.net> In <4okud8$9st@mtinsc01-mgt.ops.worldnet.att.net> Chuck Bland writes: > >Greetings, > >I'm in the process of hanging a dipole antenna, and I will be using ropes >at the ends to suspend it. > >What type of rope should I use? I live in Sacramento, CA. Hot, dry >summers, rainy, windy winters. No snow. > Polypropylene would be best as an insulator but make sure it is BLACK for UV resistance (common stuff is yellow). But, why not use a couple of cheap glass insulators? Braided Nylon is NG because it deterioriates pretty fast. Dacron is much better and stretches less. -=Tony=- W6ANV San Francisco From amsoft@epix.net Mon Jun 03 17:23:33 1996 From: bb@tisc.com (Bill Bennett) Newsgroups: rec.radio.amateur.antenna Subject: Copper cactus Date: Thu, 30 May 1996 23:52:46 GMT Message-ID: <4olccd$qtt@taxis.corp.titan.com> Some time back i saw directions and dimentions on building j-poles is there some one out there that knows the URL to find this? From amsoft@epix.net Mon Jun 03 17:23:34 1996 From: robertm@haven.ios.com (Robert Morgenstein) Newsgroups: rec.radio.amateur.antenna Subject: Re: Code Speed Change: Help Needed Date: 31 May 1996 01:23:15 GMT Distribution: world Message-ID: <4olhm3$beh@news2.ios.com> References: <8C0C395.040700095A.uuout@cheaha.com> <8C15494.040700099A.uuout@cheaha.com> ED WELCH (ed.welch@cheaha.com) wrote: : -> Rick, You really can NOT eliminate the requirement without turning : -> the bands into an uncivilized mess (eg,CB). Perhaps a lowering from : -> 13 to 10 WPM is about all the concession I'd be willing to accept. : -> This type of compromise, or : -> some concession will no doubt have to be made at some point, it's : -> just a matter : -> of time, realistically. The internet, for example has much allure : -> and is so easy and without any requirements or skills whatever, that : -> a person thinking of : Good post. : I'm studying now for my novice/tech+...nothing less than code. By the : time I test I'll *know* at least the basics involving in operating a : amateur radio station that I will be proud to say is mine. And because : I have the *desire* and *determination* I *will* pass the code. If I : didn't really care to study and practice then I wouldn't get the added : frequency priveleges. Basically, if a person wants the additional : frequency priveleges then he/she should *study* and *practice*. If that : person doesn't want to study and practice....well, he/she must not : really be serious about about the use of the HF bands. Come on folks, : the good ol' USA has been giving out free-rides for way too long, must : it enter into a long-lived and respected hobby, too? There's a : mentality of "give me" prevalent in today's society, what ever happened : to "what can I give?". : I'm studying the code, I don't feel like someone's mistreating me by : "making" me study it. Rather, I feel humbled that I live in a country : with the freedom and opportunity to do so. : ed.welch@cheaha.com To all; Just my own experience regarding code. I didnt realize what a valuble asset I had in knowing code. I recently had throat surgery and could not hold a conversation of any sustained length. I spent many happy ours " " talking " in code. Hey, no one is assured of tomorrow, you never know. Bob; WA2EAW From amsoft@epix.net Mon Jun 03 17:23:35 1996 From: macino@mail.fwi.com Newsgroups: rec.radio.amateur.antenna Subject: Re: VanGorden wire antennas? Date: 31 May 1996 01:56:54 GMT Message-ID: <4oljl6$56t@news.fwi.com> References: <4nssrr$efk@news.campus.mci.net> Reply-To: macino@mail.fwi.com In <4nssrr$efk@news.campus.mci.net>, brown@auburn.campus.mci.net (Phil Brown) writes: >Anyone using Van Gorden wire antennas? Can't seem to find the time to >make up a dipole, thought I might try one of the Van Gorden kits for >either single or multiband. Does the multiband require a tuner? How >well does the D40 load up on 15 meters? > >Thanks > > >Phil Brown N4COD >brown@auburn.campus.mci.net >Video Producer/Instructor >Like Flowers? Check out our home page at www.tigerweb.com > Phil, If you get it to work, post how you did it. I know a couple of thousand folks that would be eager to find out too. Good Luck! Jim From amsoft@epix.net Mon Jun 03 17:23:36 1996 From: dougd@lrbcg.com (KC8CGX) Newsgroups: rec.radio.amateur.antenna Subject: Just purchased MFJ-1750 5/8 wave Date: Fri, 31 May 1996 01:58:18 GMT Message-ID: <4ol8u4$2e5@news.dx.net> Reply-To: dougd@lrbcg.com Just received and installed the MFJ-1750 5/8 Groundplane. Well engineered, easy SWR adjustment (1:1.4) 146MHz For $19.95 you can't beat it. (Just don't poke yourself in the eyes with the radials while assembling). Doug KC8CGX _____________________________________________ North Central Ohio Skywarn Info http://www.amnorth.com/redbone/skywarn.html http://www.amnorth.com/redbone/ham-page.html http://lrbcg.com/dougd From amsoft@epix.net Mon Jun 03 17:23:37 1996 From: gearloos@pacbell.net (Gyro) Newsgroups: rec.radio.amateur.antenna Subject: Re: Code Speed Change: Help Needed Date: 31 May 1996 03:24:55 GMT Distribution: world Message-ID: <4oloq7$dbl@news.snfc21.pacbell.net> References: <8C0C395.040700095A.uuout@cheaha.com> <8C15494.040700099A.uuout@cheaha.com> I agree that the Code should stay. I just upgraded to a Gen(with 20 WPM)So....The Extra is hopefully in my future. Anyway, I worked for 1 hour a night for about 6 months on the Tapes and played on the air with my Tech-Plus to get to 20! It was hard but if I can do it, Anyone can. Now.......Should this Thread not be better suited to another group? It seems like every group I read has tireless postings about eliminating code. gearloos@pacbell.net In article <8C15494.040700099A.uuout@cheaha.com>, ed.welch@cheaha.com says... > Rick, You really can NOT eliminate the requirement without turning the bands into an uncivilized mess (eg,CB). Perhaps a lowering from 13 to 10 WPM is about all the concession I'd be willing to accept. This type of compromise, or some concession will no doubt have to be made at some point, it's just a matter of time, realistically. The internet, for example has much allure and is so easy and without any requirements or skills whatever, that a person thinking of >Good post. I'm studying now for my novice/tech+...nothing less than code. By the time I test I'll *know* at least the basics involving in operating a amateur radio station that I will be proud to say is mine. And because I have the *desire* and *determination* I *will* pass the code. If I didn't really care to study and practice then I wouldn't get the added frequency priveleges. Basically, if a person wants the additional frequency priveleges then he/she should *study* and *practice*. If that person doesn't want to study and practice....well, he/she must not really be serious about about the use of the HF bands. Come on folks, the good ol' USA has been giving out free-rides for way too long, must it enter into a long-lived and respected hobby, too? There's a mentality of "give me" prevalent in today's society, what ever happened to "what can I give?". I'm studying the code, I don't feel like someone's mistreating me by "making" me study it. Rather, I feel humbled that I live in a country with the freedom and opportunity to do so. ed.welch@cheaha.com From amsoft@epix.net Mon Jun 03 17:23:38 1996 From: Roger Cox <75052.3037@CompuServe.COM> Newsgroups: rec.radio.amateur.antenna Subject: Re: 2.4 GHz antennas Date: 31 May 1996 04:03:57 GMT Message-ID: <4olr3d$chd$2@mhadf.production.compuserve.com> References: <31A59CCB.24A5@ozemail.com.au> There is a BIG difference between a $A700 WLAN antenna and a US$10000 MMDS "Broadcast" antenna. WLAN is limited here in the states to 1 watt. The antenna can have no more than 6 dB gain, otherwise the transmitter output power must be reduced by the same amount that the antenna gain is over the 6 dB figure. Most of the WLAN companies transmit less than 100 mW anyway. Typical range is less than 3 miles, even when using directive antennas. Some people have gotten around the FCC limitations by using the 6 dB gain antenna only on transmit, and using 20 to 30 dB gain dishes on receive. The MMDS antenna is meant for HIGH-POWER broadcasting, and it costs more because of that. 73, Roger WB0DGF -- Roger Cox From amsoft@epix.net Mon Jun 03 17:23:39 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: design for 1/4 wave z xfmrs for 1/2" catv hardline? Date: Fri, 31 May 96 04:23:04 GMT Message-ID: <4om0fe$35k@crash.microserve.net> References: <199605271904.PAA14453@sun.lssu.edu> <4oigqk$pff@news.dx.net> <4okjk1$4e3@news.jf.intel.com> jgarver@ichips.intel.com (Jim Garver) wrote: >What I did was to take a large 75 ohm carbon resistor scrounged >from a very old radio and solder it onto an 'N' connector with >very short leads. I use this with RG-11 or up the tree on the end >of the hardline to calibrate my SWR meter mounted directly on the >back of the rig or inside. I make sure I get 1.5:1 and then I stick >on the antenna and adjust for 1.5:1 again. If a 75 ohm load attached to a 75 ohm feedline creates a reading of 1.5:1, the meter is detecting impedance, not reflected current. Under these conditions, I wonder if the same reading won't be created by more than one value of load impedance? If so, the only way to be sure the SWR on the line is 1:1 (in other words, that the antenna is actually 75 ohms), would be to vary the feedline length as a test. If varying the length a few feet causes the meter reading to change, the load isn't 75 ohms. Of course, in order to be valid, this also requires that the operator be certain there is no RF on the outside of the cable. 73, Jack WB3U From amsoft@epix.net Mon Jun 03 17:23:40 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Re: Off-centre fed dipole theory question. Date: Fri, 31 May 96 04:58:42 GMT Message-ID: <4om2i6$35k@crash.microserve.net> References: <4o5g50$3an@crash.microserve.net> <4ofrr3$1f2@hpcvsnz.cv.hp.com> <4ogopq$m6d@nnrp1.news.primenet.com> Cecil Moore wrote: >Hi Tom, just ran it in free space. Resonant frequency seems to >be the same for center-fed and off-center-fed in free space. Thanks for the info Cecil. I guess the difference you saw over ground is too small to be noticed most of the time. Just the same, I'm glad to know about this effect. 73, Jack WB3U From amsoft@epix.net Mon Jun 03 17:23:41 1996 From: Cameron Hughes <1yardbird@worldnet.att.net> Newsgroups: rec.radio.amateur.antenna,rec.radio.broadcasting,rec.radio.info,rec.radio Subject: What's a good AM tuner? Date: 31 May 1996 07:11:58 GMT Distribution: world Message-ID: <4om63u$lrp@vixen.cso.uiuc.edu> I'm looking for a superior AM tuner, currently in production, for a stereo sys tem. I need to be able to put the Kiwa Air-Core Loop antenna on it so it has to ha ve a two-post external antenna terminal. My main concerns will be sensitivity and clarity as I want to tape old-time radio programs. Thanks in advance for any help. -- ********************** Cameron Hughes ********************** **************** 1yardbird@worldnet.att.net **************** ********************* Carpe diem, baby ********************* ************************************************************ From amsoft@epix.net Mon Jun 03 17:23:42 1996 From: Doug Braun Newsgroups: rec.radio.amateur.antenna Subject: Tonna Antennas Date: Fri, 31 May 1996 09:27:24 -0700 Message-ID: <31AF1DEC.4CA6@scdt.intel.com> Does anybody have an address or phonbe number, in Europe or anywhere for this company? Do they make just VHF antennas, or orther stuff as well? Is their stuff any good? Thanks, Doug Braun N1OWU From amsoft@epix.net Mon Jun 03 17:23:43 1996 From: n8jms@cars.org (Greg Kopp (N8JMS)) Newsgroups: rec.radio.shortwave,rec.radio.swap,rec.radio.scanner,rec.ham-radio,rec.radio.amateur,rec.radio.amateur.antenna,rec.radio.amateur.digital.misc,rec.radio.amateur.dx Subject: COMPUTER SHOW / HAMFEST - June 16, 1996 (Ohio) Date: Fri, 31 May 1996 10:35:05 -0400 Message-ID: What: HAMFEST - COMPUTER SHOW - ELECTRONICS FLEA MARKET When: June 16, 1996 Time: 8AM - 1PM Where: Nordonia High School, Macedonia, Ohio (Just south of Cleveland) ------------------- Join the Cuyahoga Amateur Radio Society at its 5th annual Hamfest! This years Grand Prize: - An Icom 2350H Dual Band Mobile! And don't miss out on these door prizes: - An Icom 2GXAT 2m Handheld! - A 28.8K External Modem! - A Handheld Scanner! ------------------- Tickets are $3.00 in advance. ($4.00 at the door.) Inside Vendor Spaces are $11.00 each and include one admission ticket. Additional spaces are available for $8.00. (Inside vendor setup will be on Saturday night 6pm-9pm and Sunday morning at 6am.) Outdoor Vendor Spaces are $4.00 each. For reservations or info, call Rich James, N8FIL at 1-800-404-2282, visit our WWW site at "http://www.cars.org" or send e-mail to: hamfest@cars.org 73 de N8JMS From amsoft@epix.net Mon Jun 03 17:23:44 1996 From: chideste@xvnews.unconfigured.domain (Dale Chidester) Newsgroups: rec.radio.amateur.antenna Subject: Re: Anodizing/Protecting Copper Antennas? Date: 31 May 1996 11:48:13 GMT Message-ID: <4omm9t$loe@igate2.pt.cyanamid.com> References: <4okct6$r8l@service3.uky.edu> Reply-To: chideste@xvnews.unconfigured.domain Why bother? Copper pipe will evenutally age to the greenish patina associated with the roofs (rooves?) of very old buildings, the Statue of Liberty, etc. I've have a Cu pipe vertical dipole for 2 meters up for 10 years and it's now to the dark brown/black stage... no decrease in performance. 73, Dale N3HAL In article r8l@service3.uky.edu, hpeach@pop.uky.edu (Harold G. Peach, Jr.) wri tes: >Several years ago (late '80s or early '90s)I recall reading an article >in QST or possibly CQ Magazine on building an antenna made from copper >pipe. In the construction article it described a process of bathing >and rinsing the copper that first turned it green, then returned it to >a flat finish that would not corrode in the weather. > >I now find myself in need of the process, but unable to locate the >article. Does anyone know the process or preferably have a reference >to the article? > >Thanks, >Harold - N4FLZ >hpeach@pop.uky.edu >--- >Harold >hpeach@pop.uky.edu > From amsoft@epix.net Mon Jun 03 17:23:45 1996 From: macino@mail.fwi.com Newsgroups: rec.radio.amateur.homebrew,rec.radio.amateur.antenna Subject: Re: Just enough to hang my. . .antenna Date: 31 May 1996 13:27:21 GMT Message-ID: <4oms3p$1t4@news.fwi.com> References: <4okud8$9st@mtinsc01-mgt.ops.worldnet.att.net> Reply-To: macino@mail.fwi.com In <4okud8$9st@mtinsc01-mgt.ops.worldnet.att.net>, Chuck Bland writes: >Greetings, > >I'm in the process of hanging a dipole antenna, and I will be using ropes >at the ends to suspend it. > >What type of rope should I use? I live in Sacramento, CA. Hot, dry >summers, rainy, windy winters. No snow. > >73's > >Chuck - n6dbt > > How long is the dipole? How heavy is the wire you intend to use? How long does the rope have to be? Overall, nylon rope works pretty well. I have a 160 Meter dipole held up by thick string nylon. You can pick up a spool at a Builders Square, Lowes, etc for 4-5 bucks. About 230 feet of this heavy string. I double it, it lasts 3-4 years in very harsh northern Indi ana weather. I guess the rule of thumb is to get only what you need. Some of this 'parachute cord' will outlast you and your QTH, but it's very salty. Jim From amsoft@epix.net Mon Jun 03 17:23:46 1996 From: rtw@fuwutai.att.com (Rob Whitacre) Newsgroups: rec.radio.amateur.antenna Subject: Re: 6 Meter Antenna Recommendation/Question ??? Date: 31 May 1996 13:43:06 GMT Message-ID: <4omt1a$48a@nntpa.cb.att.com> References: In article , jean@pubs15.si.COM says... > >Hello Everyone, > >I'm looking for recommendations for 6 meter antennas (homebrew) both >omni directional and directional varieties.. Also, what polarization >is being used for FM work on 6 meters; I would guess vertical. > >I'm going to pick up a 6 meter rig "real" soon (soon as I can find one) >and start experiencing some 6 meter activity...... Might try my luck at >the Ten Tec 6 meter transverter kit for 2 meters, that way I could mess >with it in the mobile without to much fuss. > >Thanx In Advance !!! > >Rich - N8PFK For FM work (vertical), the cushcraft ringo is a decent way to go for the house. Also, Diamond and Comet make some tri-band antennas for 6, 2, 440. If you use a base loaded antenna in the car, put it in the middle of the roof. Otherwise, use a 1/4 wave and try to keep as much of the antenna above the car body as possible. For Sporadic-E, the polarization doesn't matter a whole lot. Rob WB8WQA From amsoft@epix.net Mon Jun 03 17:23:47 1996 From: rtw@fuwutai.att.com (Rob Whitacre) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.space Subject: Re: Reference for patch antennas Date: 31 May 1996 13:50:14 GMT Message-ID: <4omtem$48a@nntpa.cb.att.com> References: <4o55c4$edr@murrow.corp.sgi.com> Keywords: Tumbler, chain, fob, lock In article <4o55c4$edr@murrow.corp.sgi.com>, jimf@zoinks.corp.sgi.com says... > >I'm interested in the design of patch antennas to evaluate them as a low profile >alternative to crossed yagis, helicals etc for OSCAR work. > >I recently talked to an AMSAT rep that talked about testing the 3D birds >antennas by using them for just that, contacting FO20 or AO13 I think. > >I have looked in my references and can only find passing mention to patch >antennas and would like to know if someone can suggest a reference that goes >into dome detal such as theory of operation and design parameters. > > >Jim >KF6AGJ > Check out the "Antenna Engineering Handbook" by Jasik and Johnson. One thing you want to pay attention to with any of these omnidirectional circular polarized antennas is how the CP holds up versus elevation angle. Rob WB8WQA From amsoft@epix.net Mon Jun 03 17:23:48 1996 From: Merv Stump Newsgroups: rec.radio.amateur.antenna Subject: Loop Impedance At Frequencies Above the Design Point Date: 31 May 1996 13:53:38 GMT Message-ID: <4omtl2$9hf@mtinsc01-mgt.ops.worldnet.att.net> At Jack's (WB3U) suggestion I did a quick model of a full-wave loop on 80 meters and then checked its impedance on other bands. The loop modeled was a square 66 feet on a side, parallel to the ground and 50 feet high. The ground was specified as "average" (Dielectric Constant = 13; Conductivity ms/m=6). The following were the results: Frequency Impedance 3.8Mhz 117 -j2 7.2Mhz 280 -j215 14.2Mhz 261 -j711 28.5Mhz 707 -j785 Incidentally, the results vary considerably depending on ground and height above ground. Regards, Merv From amsoft@epix.net Mon Jun 03 17:23:49 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna,rec.radio.amateur.homebrew Subject: Re: need help with wire dipole Date: Fri, 31 May 96 14:25:15 GMT Message-ID: <4on3oj$ds0@crash.microserve.net> References: <4ogtug$ar5@crash.microserve.net> <4okuue$9st@mtinsc01-mgt.ops.worldnet.att.net> Chuck Bland wrote: >A link-coupled tuner would do the job quite nicely. Sure, it may >set technology back about 30 years, but the system would be better >than a "mere balun". The unqualified use of baluns is what has set the Amateur community back thirty years. Overlooking the advantages and versatility of link coupling on the basis of its age is akin to replacing the family sedan with a hovercraft. ;) 73, Jack WB3U From amsoft@epix.net Mon Jun 03 17:23:50 1996 From: eracjog@eraj.ericsson.se (Christer Jogenborn) Newsgroups: rec.radio.amateur.antenna Subject: 3-bnd Vertical OMTA? Date: 31 May 1996 15:00:28 GMT Message-ID: <4on1ic$o8f@erinews.ericsson.se> References: <4omv2p$mqb@erinews.ericsson.se> Reply-To: eracjog@eraj.ericsson.se OMTA - Vertical, trapless, multi-band. - just what I need for my small backyard... Anyone with feedback on the OMTA ? - as described in October 1995 QST, article by AL7KK I am looking for SWR, bandwith, and elevation plot data on the OMTA 3-bander (40,20,15m) or - are there better ones out there? Chris sm0ncl From amsoft@epix.net Mon Jun 03 17:23:51 1996 From: frank.dinger@zetnet.co.uk (Frank Dinger) Newsgroups: rec.radio.amateur.antenna Subject: Re: Anybody using Fritzel Windoms? Date: Fri, 31 May 1996 16:11:08 +0100 Message-ID: <4oq0um$h6t@roch.zetnet.co.uk> In message cluett@mv.mv.com (Jim Cluett) writes: > In article <4ok4m9$145@acme.freenet.columbus.oh.us>, > Lynn Stolz wrote: > > > >I'd like to hear from anyone using the Fritzel OCF antenna(s). > >...wondering how well you like or hate it. do you have it installed > >in the suggested inverted-vee configuration or not, etc... > > > >I am thinking of replacing my old separate 40 and 80 meter dipoles with one . > > > >Thanks, > > > >Lynn N8AJ > >-- > >Lynn Stolz N8AJ --lstolz@freenet.columbus.oh.us > I'm using the FD-4. This is a fine antenna. I'm > using it with a yaesu FT-900AT. I use it on all > bands from 80 to 10. Working great DX on all bands, > very good reports. I have no hesitation in recommending > it. Very fine quality hardware. Be careful about > having a good ground. Mine is about 45 feet in the air, > straight across (not inverted V). > hope this helps > N1TOD =======================response from GM0CSZ / KN6WH ======================= Indeed the Fritzel FD4 Windom is a good antenna ,I am using it since 1985 , but it definitely does not work on 15m (21.000 - 21.450 MHz) Frank Dinger , Inver by Tain , Ross-shire IV20 1RX - Scotland UK e-mail : gm0csz.kn6wh@ukrs.org Packet : GM0CSZ @ GB7NOS.#76.GBR.EU From amsoft@epix.net Mon Jun 03 17:23:52 1996 From: BlandRanch@worldnet.att.net (Chuck Bland) Newsgroups: rec.radio.amateur.homebrew,rec.radio.amateur.antenna Subject: Re: Just enough to hang my. . .antenna Date: 31 May 1996 16:13:21 GMT Message-ID: <4on5r1$ho7@mtinsc01-mgt.ops.worldnet.att.net> References: <4okud8$9st@mtinsc01-mgt.ops.worldnet.att.net> <4ol72c$662@dfw-ixnews9.ix.netcom.com> In article <4ol72c$662@dfw-ixnews9.ix.netcom.com>, anthonys@ix.netcom.co says... > >In <4okud8$9st@mtinsc01-mgt.ops.worldnet.att.net> Chuck Bland > writes: >> >>Greetings, >> >>I'm in the process of hanging a dipole antenna, and I will be using >ropes >>at the ends to suspend it. >> >>What type of rope should I use? I live in Sacramento, CA. Hot, dry >>summers, rainy, windy winters. No snow. >> > > Polypropylene would be best as an insulator but make sure it >is BLACK for UV resistance (common stuff is yellow). But, why not >use a couple of cheap glass insulators? > > Braided Nylon is NG because it deterioriates pretty fast. >Dacron is much better and stretches less. > > -=Tony=- W6ANV San Francisco > Well, there are insulators on the end of the antenna, but I'll need some rope to tie to the other end of the insulators to suspend the antenna in the air. Chuck - n6dbt From amsoft@epix.net Mon Jun 03 17:23:53 1996 From: parf@aol.com (Parf) Newsgroups: rec.radio.amateur.antenna Subject: Re: 1/2 wave dipole vs. full wave question. Date: 31 May 1996 18:34:53 -0400 Message-ID: <4ons6d$fnb@newsbf02.news.aol.com> References: <4okppt$ms2@shore.shore.net> Reply-To: parf@aol.com (Parf) Assuming you are still intending on center feeding the antenna: The feed impedance would be VERY high (somewhat dependent upon conductor diameter). From memory, I believe the pattern is cloverleaf- both halves are in phase. Look in the Handbook @ extended double Zepps- a little more gain and feed techniques. 73, Dale WA2YPY From amsoft@epix.net Mon Jun 03 17:23:54 1996 From: jackl@pinetree.microserve.com (WB3U) Newsgroups: rec.radio.amateur.antenna Subject: Antenna Engineering Handbook - SOLD OUT Date: Fri, 31 May 96 18:46:53 GMT Message-ID: <4onj39$j3e@crash.microserve.net> References: <19960518.163921.11119.2.redbone@juno.com> <4ojbij$1st@srvr1.engin.umich.edu> Just received a refund check from Edward R. Hamilton, Bookseller, with a note that #292338 is sold out. :( 73, Jack WB3U From amsoft@epix.net Mon Jun 03 17:23:55 1996 From: Cecil Moore Newsgroups: rec.radio.amateur.antenna Subject: Re: 1/2 wave dipole vs. full wave question. Date: 31 May 1996 20:07:02 -0700 Message-ID: <4ooc4m$jqn@nnrp1.news.primenet.com> References: <4okppt$ms2@shore.shore.net> <4ons6d$fnb@newsbf02.news.aol.com> Parf wrote: : From memory, I believe the pattern is cloverleaf- both halves are in : phase. A full-wave is not cloverleaf. A 1.25 WL is maximum broadside gain and is still not cloverleaf. You have to get above 1.25 WL for it to be cloverleaf. It is definitely a beautiful cloverleaf by 1.7 WL. 73, Cecil, KG7BK (W6RCA soon), OOTC