Date: Fri, 3 Jun 94 04:30:22 PDT From: Ham-Ant Mailing List and Newsgroup Errors-To: Ham-Ant-Errors@UCSD.Edu Reply-To: Ham-Ant@UCSD.Edu Precedence: Bulk Subject: Ham-Ant Digest V94 #168 To: Ham-Ant Ham-Ant Digest Fri, 3 Jun 94 Volume 94 : Issue 168 Today's Topics: about tunning 3el. YAGI Antenna 4 Sale Balun question (3 msgs) Dipole help (3 msgs) Grid Dip Oscillator or Noise Bridge? Ham-Ant Digest V94 #166 Ham-Ant Digest V94 #167 modeling of a jpole Noise bridge - use your attenuator Opinion on Alpha-Delta SWL sloper stationmaster radomes wear out! Taking apart and putting together antennas Want to hear your experience with AEA Isoloop. Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Ham-Ant Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-ant". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. ---------------------------------------------------------------------- Date: 2 Jun 1994 21:06:08 -0000 From: news.delphi.com!news.delphi.com!not-for-mail@uunet.uu.net Subject: about tunning 3el. YAGI To: ham-ant@ucsd.edu I use a YAGI 3 elements for 28 MHz (LEM 3D) in vertical position. Has SWR =1 from 27.550 to 27.750 I use it to long (est) distances Should I but it in horizontal position? Some more info about these antennas please too. makis savaidis (intersof@cperi.forth.gr) TH935 THESSALONIKI - MAKEDONIA - HELLAS ------------------------------ Date: Thu, 2 Jun 1994 22:53:08 GMT From: unify!Unify.com!gfaus@uunet.uu.net Subject: Antenna 4 Sale To: ham-ant@ucsd.edu I'm posting this for a friend, please don't respond to me directly! For Sale: Cushcraft R-5 vertical in excellent condition. 5 bands, 10 thru 20 meters. Pickup in Sacramento, CA area only. $150.00 Please contact Tim, KM6AS @ (916) 983-1191. -- +==================================================================+ |"When you reach a fork in the road, take it!" | |Yogi Berra | | | | | |\_ \_ \_ \_ \_ \_\_\_\_ \_ \_ | Glenn Faus KD6VNR | | \_ \_ \_\_ \_ \_ \_ \_ \_ | Systems Administrator | | \_ \_ \_ \_ \_ \_ \_\_\_ \_\_ | Unify Corp. | | \_ \_ \_ \_\_ \_ \_ \_ | gfaus@sac.unify.com | | \_\_\_\_ \_ \_ \_ \_ \_ | Voice: (916) 928-6271 | +==================================================================+ ------------------------------ Date: Thu, 02 Jun 94 10:29:12 EDT From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!usenet.ins.cwru.edu!ns.mcs.kent.edu!kira.cc.uakron.edu!malgudi.oar.net!hypnos!voxbox!jgrubs@network.ucsd.edu Subject: Balun question To: ham-ant@ucsd.edu -----BEGIN PGP SIGNED MESSAGE----- smithson@ACM.ORG writes: > Greetings! > > I have an 80m dipole with a Van Gordon 1:1 balun at the feed point, with > 60' of RG58/U coax running to my shack. For giggles one night I put my > ohmmeter across the inner conductor and the shield and it read 0! I > fished out a spare balun of the same type and measured it both between the > poles where the legs of the dipole are connected and between the center > and sheild of the coax jack - both read 0. An ohmmeter is a DC device. It tells you little about what's happening with RF at 80 meters. -----BEGIN PGP SIGNATURE----- Version: 2.6 iQCVAwUBLe3tSDDUWq8RWEeNAQFSNQP+K/hYSEvv+/QhQ3rCw6hvucIdQM+bmT4i AGl3zst5i4dV0j4oXUcMkMqlwJdJ+fbylyzunedlCGXcGeWctyCGdRgftT/V2Kpw j8fiqEnR4K1xTT/n/XKfZ+OEinYOAExKqh5+nVcFqB1weNE+OrZ5ChxMbr2aYmQE JH5+QmGtufQ= =bWyR -----END PGP SIGNATURE----- +--------------------------------------------------------------------------+ | Jim Grubs, W8GRT Voxbox Enterprises THIS SPACE FOR RENT | | jgrubs@voxbox.norden1.com 6817 Maplewood Ave. RATES REASONABLE | | Fido: 1:234/1.0 Sylvania, Ohio 43560 Home: 419/882-2697 | | AMATEUR RADIO - The National Park of the Mind | +--------------------------------------------------------------------------+ ------------------------------ Date: 2 Jun 1994 16:08:15 GMT From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!cs.utexas.edu!convex!news.duke.edu!eff!news.kei.com!ssd.intel.com!chnews!cmoore@network.ucsd.edu Subject: Balun question To: ham-ant@ucsd.edu smithson@ACM.ORG wrote: : educated, I see that two kinds really exist; voltage and current. Looking : at the schematics for both, it looks to me like a voltage balun should : appear to be shorted at DC while a current balun should not. The book : also recommends a current balun for this type of application. : Brian n8wrl (soon to be /ag) Hi Brian, there's another kind of balun called a choke balun where you just slip ferrite cores over the coax. I have tried all three kinds on my non-resonant dipole and find the Amidon HBHT200 to be the best for me. It is a high power voltage balun rated at least ten times my power level. IMHO, if you obtain voltage baluns rated at ten times your power output, they will not "blow up". My high power MFJ current balun is flakey on a couple of bands and the choke approach didn't work at all for me. Don't try using the baluns built into 300w tuners with non-resonant antennas and 100 watts. They will saturate. However, the balun built into my MFJ-989 3kw tuner worked fine and never saturated at 100w. 73, KG7BK, CecilMoore@delphi.com ------------------------------ Date: 2 Jun 1994 16:46:54 GMT From: ihnp4.ucsd.edu!library.ucla.edu!europa.eng.gtefsd.com!news.umbc.edu!eff!news.kei.com!ssd.intel.com!chnews!cmoore@network.ucsd.edu Subject: Balun question To: ham-ant@ucsd.edu smithson@ACM.ORG wrote: : I have an 80m dipole with a Van Gordon 1:1 balun at the feed point, with : Brian n8wrl (soon to be /ag) Hello again, Brian. I forgot to ask what is the power rating of your Van Gordon balun and how much power are you running? Also, a balun that has low DC resistance bleeds static electricity off the antenna which is a very good feature in my extremely high static electricity environment here in Arizona. When I used to run a G5RV with a choke balun, I could hear arcing inside my transceiver because of static electricity on the antenna. 73, KG7BK, CecilMoore@delphi.com ------------------------------ Date: 2 Jun 1994 18:22:14 GMT From: ihnp4.ucsd.edu!library.ucla.edu!psgrain!news.tek.com!tekgp4.cse.tek.com!royle@network.ucsd.edu Subject: Dipole help To: ham-ant@ucsd.edu I wrote: >. . . In all modern rigs I know of, the AGC can't be disabled. . . I stand corrected! Some modern rigs DO permit disabling of the AGC. At least the TS-930 and FT-990 have this capability. Thanks to N4ZR and KD1ON for correcting me. Roy Lewallen, W7EL roy.lewallen@tek.com ------------------------------ Date: 2 Jun 1994 19:01:11 GMT From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!vixen.cso.uiuc.edu!usenet@network.ucsd.edu Subject: Dipole help To: ham-ant@ucsd.edu In <2sl80m$e53@tekadm1.cse.tek.com>, royle@tekgp4.cse.tek.com (Roy W Lewallen) writes: >I wrote: > >>. . . In all modern rigs I know of, the AGC can't be disabled. . . > >I stand corrected! Some modern rigs DO permit disabling of the AGC. >At least the TS-930 and FT-990 have this capability. Thanks to N4ZR and >KD1ON for correcting me. > >Roy Lewallen, W7EL >roy.lewallen@tek.com > AGC can be disabled in most if not all of high-class rigs. I have heard that this feature is often used by top DX hunters. Ignacy Misztal Ham radio: NO9E, SP8FWB E-mail: ignacy@uiuc.edu University Of Illinois 1207 W. Gregory Dr., Urbana, IL 61801, USA tel. (217) 244-3164 Fax: (217) 333-8286 ------------------------------ Date: 2 Jun 1994 20:16:07 GMT From: ihnp4.ucsd.edu!swrinde!howland.reston.ans.net!europa.eng.gtefsd.com!newsxfer.itd.umich.edu!zip.eecs.umich.edu!yeshua.marcam.com!news.kei.com!ssd.intel.com!chnews!cmoore@network.ucsd.edu Subject: Dipole help To: ham-ant@ucsd.edu Ignacy Misztal (ignacy@misz.animal.uiuc.edu) wrote: : AGC can be disabled in most if not all of high-class rigs. I have : heard that this feature is often used by top DX hunters. : Ignacy Misztal Ham radio: NO9E, SP8FWB Hi Ignacy, disabling the AGC is especially helpful when trying to receive a weak signal in the presence of a strong signal when using an audio filter on CW... Notch the strong one and peak the weak one. 73, KG7BK, CecilMoore@delphi.com ------------------------------ Date: 2 Jun 1994 12:26:16 GMT From: agate!howland.reston.ans.net!news.moneng.mei.com!sol.ctr.columbia.edu!news.kei.com!ssd.intel.com!chnews!scorpion.intel.com!jbromley@ames.arpa Subject: Grid Dip Oscillator or Noise Bridge? To: ham-ant@ucsd.edu In article <2sht8j$hp@chnews.intel.com>, I wrote: [ Regarding Jerald's matching his antenna with a transmatch ] [ and bridge, the article *should* have read: ] For the receive-only bands, build a crystal calibrator (see the Amateur's Handbook), couple it to the antenna by means of its own small antenna and tune for maximum S-meter reading on the calibrator harmonic closest to the frequency of interest. Jim, W5GYJ ------------------------------ Date: 2 Jun 94 12:57:52 GMT From: news-mail-gateway@ucsd.edu Subject: Ham-Ant Digest V94 #166 To: ham-ant@ucsd.edu Hi Roy -- delighted to see you on the net. Just one very minor quibble with your posting -- my TS-930 has an AGC off switch setting (of course, maybe it's not a modern rig any more ). Real reason for the note is to ask about present status of Elnec. I have a copy of 2.0 and like it a lot, but don't know/recall what the current version is or how it differs. 73, Pete 2003 Sarazen Pl. n4zr@netcom.com Reston, VA 22091 N4ZR@N4OHE (PacketCluster) ------------------------------ Date: 3 Jun 94 03:12:12 GMT From: news-mail-gateway@ucsd.edu Subject: Ham-Ant Digest V94 #167 To: ham-ant@ucsd.edu I have a noise bridge, grid dip oscillator and the mfj swr analyzer.....if I could have one it would be the mfj swr machine.....I use it 9 out of 10 times when working on antennas. ******************************************************************************----------------------------------------------------------------------------- Dr. Rick Zabrodski BSc, MD, CCFP(E) * VE6GK "glider king" EMAIL: zabrodsk@med.ucalgary.ca * "M.D. on weekdays" Packet: VE6GK@VE6YYC.#cgy.ab.can.na * "Solar powered aviator Phone: (403) 271-5123 Fax: 225-1276 * on weekends!" ****************************************************************************** ------------------------------ Date: 2 Jun 94 15:26:29 GMT From: news-mail-gateway@ucsd.edu Subject: modeling of a jpole To: ham-ant@ucsd.edu Has anyone modeled a j-pole with ELNEC, Mininec,... I set it up as follows | | | | | | | | | | | |------feed point here. | | The results i get seem to indicate too high a takeoff angle (~30 degrees). I thought it was lower (about 15-18 degrees). I was looking at a 2m design. Any ideas? Thanks. end the views expressed here are the author's C. Harper harper@huntsville.sparta.com or kd4qio@amsat.org KD4QIO SPARTA Inc (205) 837-5282 x1216 voicemail 4901 Corporate Drive (205) 830-0287 FAX Huntsville AL 35805 "we have met the enemy and he is us." w. kelly ------------------------------ Date: 2 Jun 1994 14:18:02 GMT From: ihnp4.ucsd.edu!agate!msuinfo!netnews.upenn.edu!eniac.seas.upenn.edu!depolo@network.ucsd.edu Subject: Noise bridge - use your attenuator To: ham-ant@ucsd.edu I've found that when trying to tune a noise bridge for a null when using modern solid-state rigs, flipping the attenuator in line often makes finding the null easier, and also gives a more reliable reading. This is because many receivers don't have true 50 ohm input impedances, but putting the attenuator in line will make it look close to 50 ohms (assuming the attenuator was designed well). If you're unsure of the quality of the internal attenuator in the rig, use a high-quality external one. Usually 20 dB works well with the bridge I use. --- Jeff -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Jeff DePolo WN3A Twisted Pair: (215) 337-7383H 387-3059W depolo@eniac.seas.upenn.edu RF: 443.800+ MHz 442.400+ MHz 24.150 GHz ------------------------------ Date: Thu, 2 Jun 1994 22:27:30 GMT From: ihnp4.ucsd.edu!usc!elroy.jpl.nasa.gov!lll-winken.llnl.gov!fnnews.fnal.gov!gw1!nntpa!not-for-mail@network.ucsd.edu Subject: Opinion on Alpha-Delta SWL sloper To: ham-ant@ucsd.edu Anyone out there have any experience with the Alpha-Delta sloper antenna for SWL reception?? I have about 75 feet from my tower to an unused utility pole and have been thinking about stringing up a long wire. I saw an ad for the SWL sloper which might fit the bill. It apparently covers all of the popular SW bands and terminates to 50 ohm coax. Thanks, in advance, for any responses. Terry -- Terry Florek WB9QDM AT&T Consumer Products Labs, Indianapolis, Indiana ------------------------------ Date: Thu, 02 Jun 1994 21:57:00 -0500 From: ihnp4.ucsd.edu!usc!cs.utexas.edu!swrinde!gatech!psuvax1!hsdndev!NewsWatcher!user@network.ucsd.edu Subject: stationmaster radomes wear out! To: ham-ant@ucsd.edu I recently asked for help to figure out why two Sincalir stationmaster repeater antennas(2M & 220) had both developed hi SWR and were leaking water down into the pigtail. Well, we recently removed the two antennas and they both showed the same incredible finding. The outer shiny white plastic coating of the radome was completely gone. The middle layer of fibreglass wrapping was exposed! Looks like 4 years of central Vermont wind at just under 2000'(both top mounted) had sufficient abrasive strength to strip off the outer porotective coat and allow water in! I had never heard of this. Does this happen at all repeater sites? Is the Sinclair radome not as strong as other radomes (Celwave, etc)? Frank -- Frank H. Duffy, MD e-mail: duffyfr@a1.tch.harvard.edu Neurology, Childrens Hospital workstation: fhd@fhd486.harvard.edu & Harvard Medical School FAX: (617) 735-7230 300 Longwood Avenue voice: (617) 735-7919 / 7846 Boston, MA 02115 USA amateur radio: K1MOQ ------------------------------ Date: 2 Jun 1994 23:58:06 -0500 From: ihnp4.ucsd.edu!usc!cs.utexas.edu!not-for-mail@network.ucsd.edu Subject: Taking apart and putting together antennas To: ham-ant@ucsd.edu I am wondering what the best way to cut antennas and then put them together. After cutting them (in the least important place I have three methods for putting them together (that I have used on masts and limited use on antennas) which do any of you think works best? 1) Insert wodden dowel rod (that is slightly smaller than inner diameter of tube) into tube, and lock into place (both horizontaly and radially) with a set screw - after drilling holes in both pieces. To ensure a good electrical connection, fasten gap with a hose clamp. 2) Crimp one piece of metal, and stick it inside the other (well, RadioShack does it) 3) Obtain a pipe slightly larger than the diameter being cut. Use it as a sleave (perhaps with set screws) to hold the two pipes together. 4) Combine 1 and 3. Maybe this is overkill? I would hate to waste $500 worth of aluminium. 73 Dave/KA1NCN caseda@ecsuc.ctstateu.edu ------------------------------ Date: Thu, 2 Jun 1994 13:22:26 GMT From: nntp.cadence.com!fonzie!pmohan@uunet.uu.net Subject: Want to hear your experience with AEA Isoloop. To: ham-ant@ucsd.edu Hello: I am presently considering buying an AEA Isoloop for HF. Does someone here have experience with this antenna? Please let me know about the effectiveness of this antenna for HF, if used in an apartment balcony on the third floor. Thanks very much for your help. //Mohan -- < < __o < > KB8PIP `\< o/ > > ()/ () /| // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ------------------------------ End of Ham-Ant Digest V94 #168 ******************************