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- Date: Fri, 4 Feb 94 16:43:55 PST
- From: Info-Hams Mailing List and Newsgroup <info-hams@ucsd.edu>
- Errors-To: Info-Hams-Errors@UCSD.Edu
- Reply-To: Info-Hams@UCSD.Edu
- Precedence: Bulk
- Subject: Info-Hams Digest V94 #113
- To: Info-Hams
-
-
- Info-Hams Digest Fri, 4 Feb 94 Volume 94 : Issue 113
-
- Today's Topics:
- "Flexible" 9913 (Was - Re: Coaxial cable)
- A code speed question
- Automotive computers and amateur radios - Help!
- call book typo... sorry
- CQ NR
- Field Day Logging Program
- Global Alert For All: Jesus is Coming Soon
- htx-202 or dj-162 ?
- ORBS$035.2L.AMSAT
- SAREX Element Set for 2/4/94
- simple ohm meter
-
- Send Replies or notes for publication to: <Info-Hams@UCSD.Edu>
- Send subscription requests to: <Info-Hams-REQUEST@UCSD.Edu>
- Problems you can't solve otherwise to brian@ucsd.edu.
-
- Archives of past issues of the Info-Hams Digest are available
- (by FTP only) from UCSD.Edu in directory "mailarchives/info-hams".
-
- 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: Fri, 4 Feb 1994 21:25:35 GMT
- From: news.sprintlink.net!direct!kg7bk@uunet.uu.net
- Subject: "Flexible" 9913 (Was - Re: Coaxial cable)
- To: info-hams@ucsd.edu
-
- Steve Bunis SE Southwest Chicago (doc@webrider.central.sun.com) wrote:
- : > Some other things to keep in mind about 9913. Remember that you'll need
- : > special UHF N connectors if you plan on using the cable for UHF
- : > applications.
-
- : Also, regarding the N connectors, at what point do they start making
- : a discernible difference? I thought that NMO was supposed to do well
- : at least past the 70cm. band. -- Steve Bunis
-
- My dual-band 2x4MAX Comet has an so239 connector on it. Just how bad
- is a pl259 connection on UHF? Should I use an N to so239 adapter? I
- use 9913 on HF with pl259s and some copper tape.
-
- thanks, Cecil, kg7bk@indirect.com
-
- ------------------------------
-
- Date: 3 Feb 1994 12:21:00 GMT
- From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!xlink.net!scsing.switch.ch!swidir.switch.ch!univ-lyon1.fr!elendir@network.ucsd.edu
- Subject: A code speed question
- To: info-hams@ucsd.edu
-
- Okay, thanks a lot to everybody. I guess I'll try to set up a practice.
- Wouldn't be easy though.
-
- Hopefully for me, the French exam for the "Full license" (Class E) is only
- 10 wpm.
-
- Thanks again.
-
- Vince.
-
- ------------------------------
-
- Date: 3 Feb 1994 15:09:48 GMT
- From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!news.moneng.mei.com!uwm.edu!vixen.cso.uiuc.edu!newsrelay.iastate.edu!news.iastate.edu!kenman@network.ucsd.edu
- Subject: Automotive computers and amateur radios - Help!
- To: info-hams@ucsd.edu
-
- In article <2ipc91$893@iris.mbvlab.wpafb.af.mil> engberg@edfue0.ctis.af.mil (Bob Engberg) writes:
- >Mike,
- >I once had my Plymouth Reliant die momentarily when I keyed the 2 mtr rig.
- >45 watts to a wet 1/4 wave mag mount. No problem when it's dry.
- >When I keyed the transmitter, the electronic fuel injection stopped.
- >Not a problem if your going down hill, I suppose.
- >
-
- When I speak into my 2 mtr HT my electric wheelchair instantly powers up and
- moves at full speed (abt 7 mph). It only took once, and some broken
- furniture, to remember to shut off my wheelchair before transmitting. 8)
-
-
-
-
-
-
- --
- Ken Anderson N0ZEM Kenman@iastate.edu PH: 515.294.8996
- 126 Soil Tilth Bldg., Iowa State University, Ames, Iowa 50011
-
- ------------------------------
-
- Date: Thu, 3 Feb 1994 08:27:50 GMT
- From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!darwin.sura.net!rouge!cfm1471@network.ucsd.edu
- Subject: call book typo... sorry
- To: info-hams@ucsd.edu
-
- >I made a mistake on my end here, BAD typo! The correct address should be:
- >
- >cs.buffalo.edu 2000 or 128.205.32.2
- >
- >again, the word 'callsign' was not needed here. sorry for the trouble.
- >
- > 73 to all - shawn
-
- Try pc.usl.edu 2000.
-
- Charlie
-
- ------------------------------
-
- Date: 3 Feb 1994 15:13:17 GMT
- From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!news.moneng.mei.com!uwm.edu!fnnews.fnal.gov!att-in!news.bu.edu!transfer.stratus.com!sw.stratus.com!fms@network.ucsd.edu
- Subject: CQ NR
- To: info-hams@ucsd.edu
-
- brunob@hpldsla.sid.hp.com (Bruno Bienenfeld) writes:
- > Just a reminder that yearly Novice Roundup is ON.
- > Would appriciate any/all G/A/E level hams to extend there generous help
- > and if only for one QSO contribute to the glory of our wonderful hobby.
- >
- > Yes it can be borring to work at 4wpm but try to remember when you started.
- >
-
- Absolutely, get on the air and work the NR! It's a great way to help out
- Novices & Techs aspiring to upgrade (that's how I got _my_ General, anyways!).
- It's a great practice session for those aspiring Novices & Techs, too.
-
- But for this one poor Advanced who hasn't touched CW in almost 2 years, the
- code speeds that some of these whiz-kids are working at are just too fast!
- I only wish I _could_ find somebody working at 4WPM!!! :-) :-)
-
- Oh, one small hint to those of you who work the contest. If you're calling CQ,
- PLEASE send your callsign more than once! I was listening to one fellow the
- other night who was sending his CQ's like this:
-
- CQ NR CQ NR CQ NR DE KE4xxx/N K
-
- It took me three complete QSOs to finally figure out what his full call was,
- because he never sent it often enough for me (the fact that he was running at
- about 12WPM and I can't copy terribly cleanly above 10 didn't help matters
- much, either :) He worked one person at about the same code speed he was at,
- one person running down around my speed who was obviously using a straight key
- and equally obviously going too fast for himself, and one person running at
- something close to 15WPM. On KE4's next CQ, I finally got the last letters of
- the call confirmed. BOY am I out of practice on this stuff! :-)
-
- 73 de Faith N1JIT
- --
- Faith M. Senie InterNet: fms@vos.stratus.com
- Stratus Computer, Inc. InterNet: fms@hoop.sw.stratus.com
- 55 Fairbanks Blvd. Pkt Radio: n1jit@wa1phy.ma.usa.na
- Marlboro, MA 01752 Phone: (508)460-2632
-
- Curiosity doesn't flourish among the burned-out...
-
- ------------------------------
-
- Date: Thu, 3 Feb 1994 15:54:31 GMT
- From: netcomsv!netcom.com!greg@decwrl.dec.com
- Subject: Field Day Logging Program
- To: info-hams@ucsd.edu
-
- In article <9402031354.AA23136@nms1.abb.com> jennings@eng115.rochny.USpra.abb.COM (Tom_Jennings) writes:
- >Hello,
- >
- >Well it's time to start planning for Field Day. It's my job
- >to find a good logging program.
-
- ESPN runs the lumberjack championships every so often. You could
- tape them, but who has time to watch TV on Field Day?
-
- Anyway, an axe or chainsaw works better than a floppy disk, but
- isn't it more effective to just shoot a wire over the top. Besides,
- it isn't right to chop down a bunch of trees, just to make a
- clearing for Field Day. I know it isn't called 'Forest Day,'
- but you don't HAVE to have a field.
-
- Greg
-
- ------------------------------
-
- Date: Mon, 31 Jan 1994 23:53:55 GMT
- From: netcomsv!netcom.com!marcbg@decwrl.dec.com
- Subject: Global Alert For All: Jesus is Coming Soon
- To: info-hams@ucsd.edu
-
- William Osborne (wosborne@nmsu.edu) wrote:
- : Where is the radio to swap or sell?? Why do we have to put up with
- : the nonsense in this group?
-
- I believe that Jesus is now on-line, WA5CHRIST. Works 40 and 80 and is
- setting up a special events station for Easter (naturally, he's a little
- depressed around the season and mentioned something about a banquet - we
- all thought it was a bad idea).
-
- Of course, the question we all ask: Why does Jesus have a 5 call?
- --
- Marc B. Grant fax 214-231-3998 voice 214-246-1150
- marcbg@netcom.com Amateur Radio N5MEI
- marcbg@esy.com Richardson, TX
-
- ------------------------------
-
- Date: Wed, 2 Feb 1994 20:51:27 GMT
- From: rit!sunsrvr6!jdc@cs.rochester.edu
- Subject: htx-202 or dj-162 ?
- To: info-hams@ucsd.edu
-
- In article <2i8rnf$o5n@explorer.clark.net>,
- matt roberts <robocop@clark.net> wrote:
- >In article <ah301-260194121225@129.228.248.39>,
- >Jerry Sy <ah301@yfn.ysu.edu> wrote:
- >>I have pretty much narrowed down my choice to these two 2m ht's.
- >
- >>I'd like to get comments and opinions from people in the net who
- >>have actually used both.
- >>currently, I am leaning towards the dj-162 because of its wide
- >>receive.
- >
- >The HTX202 is a good radio. It comes with the CTCSS, DTMF squelch, and
- >it can store telephone numbers. It has 14 memories, I think.
- >
- > Matt Roberts N3GZM
-
- I'll second the motion. The HTX-202 is also more sensitive on receive
- than my ICOM-27H, of a late 70's or early 80's vintage. And the price
- is right when Radio Shack runs one of their periodic "sales".
-
- 73...Jim
- N2VNO
-
- ------------------------------
-
- Date: 4 Feb 94 13:38:00 GMT
- From: news-mail-gateway@ucsd.edu
- Subject: ORBS$035.2L.AMSAT
- To: info-hams@ucsd.edu
-
- SB KEPS @ AMSAT $ORBS-035.N
- 2Line Orbital Elements 035.AMSAT
-
- HR AMSAT ORBITAL ELEMENTS FOR AMATEUR SATELLITES IN NASA FORMAT
- FROM WA5QGD FORT WORTH,TX February 4, 1994
- BID: $ORBS-035.N
-
- DECODE 2-LINE ELSETS WITH THE FOLLOWING KEY:
- 1 AAAAAU 00 0 0 BBBBB.BBBBBBBB .CCCCCCCC 00000-0 00000-0 0 DDDZ
- 2 AAAAA EEE.EEEE FFF.FFFF GGGGGGG HHH.HHHH III.IIII JJ.JJJJJJJJKKKKKZ
- KEY: A-CATALOGNUM B-EPOCHTIME C-DECAY D-ELSETNUM E-INCLINATION F-RAAN
- G-ECCENTRICITY H-ARGPERIGEE I-MNANOM J-MNMOTION K-ORBITNUM Z-CHECKSUM
-
- TO ALL RADIO AMATEURS BT
-
- AO-10
- 1 14129U 83058B 94026.96316316 -.00000226 00000-0 10000-3 0 2568
- 2 14129 27.2068 344.5815 6022530 149.7185 266.2880 2.05879387 79879
- UO-11
- 1 14781U 84021B 94032.08509882 .00000402 00000-0 76155-4 0 6614
- 2 14781 97.7914 53.1385 0012207 350.8426 9.2555 14.69134627530327
- RS-10/11
- 1 18129U 87054A 94032.53118575 .00000050 00000-0 37815-4 0 8585
- 2 18129 82.9221 69.1201 0013160 45.5265 314.6964 13.72330706331309
- AO-13
- 1 19216U 88051B 94030.92643199 .00000280 00000-0 10000-4 0 8703
- 2 19216 57.8741 270.6815 7209428 333.8315 3.2375 2.09718964 43137
- FO-20
- 1 20480U 90013C 94031.53669543 -.00000027 00000-0 19778-4 0 6550
- 2 20480 99.0172 209.2767 0540316 289.1742 65.1641 12.83223743186608
- AO-21
- 1 21087U 91006A 94031.03739220 .00000094 00000-0 82657-4 0 4201
- 2 21087 82.9409 244.1976 0036680 104.7675 255.7549 13.74532587150747
- RS-12/13
- 1 21089U 91007A 94031.70193410 .00000042 00000-0 28589-4 0 6594
- 2 21089 82.9219 112.6758 0030259 126.1313 234.2652 13.74034091149908
- UO-14
- 1 20437U 90005B 94032.74755041 .00000069 00000-0 43836-4 0 9602
- 2 20437 98.5970 119.3308 0010282 228.1065 131.9239 14.29820416210231
- AO-16
- 1 20439U 90005D 94032.73834399 .00000056 00000-0 38818-4 0 7616
- 2 20439 98.6037 120.4137 0010538 229.1624 130.8644 14.29876054210245
- DO-17
- 1 20440U 90005E 94032.21605654 .00000059 00000-0 39911-4 0 7608
- 2 20440 98.6061 120.1794 0010670 230.1283 129.8974 14.30014080210182
- WO-18
- 1 20441U 90005F 94032.74877680 .00000059 00000-0 39913-4 0 7610
- 2 20441 98.6045 120.7143 0011238 228.7469 131.2742 14.29990577210260
- LO-19
- 1 20442U 90005G 94032.73595222 .00000060 00000-0 40140-4 0 7604
- 2 20442 98.6061 120.9273 0011579 227.6391 132.3802 14.30084334210272
- UO-22
- 1 21575U 91050B 94032.20992261 .00000092 00000-0 45713-4 0 4613
- 2 21575 98.4468 109.3768 0007973 342.8458 17.2467 14.36886367133551
- KO-23
- 1 22077U 92052B 94032.56421641 -.00000037 00000-0 10000-3 0 3565
- 2 22077 66.0829 203.9397 0009202 321.5390 38.4975 12.86284168 69344
- AO-27
- 1 22825U 93061C 94028.69364623 .00000013 00000-0 23328-4 0 2573
- 2 22825 98.6656 105.8249 0007962 258.9140 101.1150 14.27603315 17787
- IO-26
- 1 22826U 93061D 94028.75480372 .00000020 00000-0 26215-4 0 2588
- 2 22826 98.6650 105.9020 0008479 259.3938 100.6287 14.27705864 17792
- KO-25
- 1 22830U 93061H 94027.67578287 .00000027 00000-0 28271-4 0 2598
- 2 22830 98.5680 103.5736 0010863 227.3626 132.6641 14.28029120 17644
- NOAA-9
- 1 15427U 84123A 94030.85754099 .00000106 00000-0 80549-4 0 6983
- 2 15427 99.0709 79.6136 0014249 247.4940 112.4724 14.13584243470947
- NOAA-10
- 1 16969U 86073A 94030.87446357 .00000080 00000-0 52487-4 0 5977
- 2 16969 98.5113 44.0548 0013983 14.1154 346.0414 14.24860838383050
- MET-2/17
- 1 18820U 88005A 94031.88812903 .00000057 00000-0 37729-4 0 2588
- 2 18820 82.5389 17.0036 0015453 200.0821 159.9741 13.84705936303495
- MET-3/2
- 1 19336U 88064A 94027.46247972 .00000051 00000-0 10000-3 0 2590
- 2 19336 82.5373 63.2695 0015606 255.3337 104.6056 13.16963718264738
- NOAA-11
- 1 19531U 88089A 94030.90850576 .00000129 00000-0 94376-4 0 5012
- 2 19531 99.1598 16.5427 0011803 155.4181 204.7555 14.12954794275834
- MET-2/18
- 1 19851U 89018A 94032.05387033 .00000055 00000-0 36448-4 0 2595
- 2 19851 82.5189 252.4483 0012906 250.2891 109.6871 13.84356477248859
- MET-3/3
- 1 20305U 89086A 94031.24041489 .00000044 00000-0 10000-3 0 9790
- 2 20305 82.5524 4.6588 0005865 275.4667 84.5785 13.04422822205046
- MET-2/19
- 1 20670U 90057A 94027.78170716 .00000024 00000-0 79036-5 0 7595
- 2 20670 82.5487 319.9935 0015537 175.8931 184.2364 13.84187490181198
- FY-1/2
- 1 20788U 90081A 94031.24189156 -.00000218 00000-0 -11642-3 0 8816
- 2 20788 98.8450 55.7276 0015225 34.8287 325.3871 14.01328583174523
- MET-2/20
- 1 20826U 90086A 94032.06418741 .00000067 00000-0 47107-4 0 7590
- 2 20826 82.5234 254.2791 0014796 68.6622 291.6123 13.83571908168937
- MET-3/4
- 1 21232U 91030A 94032.12779086 .00000051 00000-0 10000-3 0 6673
- 2 21232 82.5420 265.7828 0013008 161.7732 198.3861 13.16459852133456
- NOAA-12
- 1 21263U 91032A 94030.88246322 .00000153 00000-0 88168-4 0 9073
- 2 21263 98.6341 61.5947 0012159 276.6165 83.3630 14.22362615141012
- MET-3/5
- 1 21655U 91056A 94031.52098998 .00000051 00000-0 10000-3 0 6635
- 2 21655 82.5520 213.2454 0012989 174.8683 185.2566 13.16827699118476
- MET-2/21
- 1 22782U 93055A 94032.21037544 .00000059 00000-0 40822-4 0 2590
- 2 22782 82.5501 314.1919 0020900 247.4078 112.4878 13.82998426 21292
- MIR
- 1 16609U 86017A 94031.87716614 .00012295 00000-0 15584-3 0 1202
- 2 16609 51.6174 150.3786 0004081 270.2389 89.8133 15.59884699454786
- HUBBLE
- 1 20580U 90037B 94030.88685201 .00001105 00000-0 95570-4 0 4327
- 2 20580 28.4686 37.8356 0006388 94.2779 265.8536 14.90449228 8888
- GRO
- 1 21225U 91027B 94031.58821780 .00005286 00000-0 12231-3 0 609
- 2 21225 28.4626 99.8409 0003960 118.3199 241.7802 15.39951744 35854
- UARS
- 1 21701U 91063B 94030.49811085 -.00001766 00000-0 -13392-3 0 4686
- 2 21701 56.9857 350.7923 0004837 107.9039 252.2522 14.96284426130328
- POSAT
- 1 22829U 93061G 94032.79331938 .00000070 00000-0 46180-4 0 2514
- 2 22829 98.6598 109.9146 0009385 231.2681 128.7662 14.28000972 18372
- /EX
-
- ------------------------------
-
- Date: 4 Feb 94 16:00:24 GMT
- From: news-mail-gateway@ucsd.edu
- Subject: SAREX Element Set for 2/4/94
- To: info-hams@ucsd.edu
-
- SB SAREX @ AMSAT $STS-60.006
- STS-60 Element Set for 2/4/94
-
- The official SAREX element set for today will be GSFC-003. Gil Carman,
- WA5NOM reports that the predictions using GSFC-003 are 9 seconds later than
- with JSC-004. Element set GSFC-003, developed by Ron Parise, WA4SIR, and
- shown below, is consistent with the current orbiter state vector.
-
-
- 1 22977U 94006A 94 35.13981770 0.00000202 00000-0 58718-5 0 37
- 2 22977 56.9857 213.2731 0008535 263.0773 96.9324 15.72145611 115
-
- Satellite: STS-60
- Catalog number: 22977
- Epoch time: 94035.13981770 (04 FEB 94 03:21:20.25 UTC)
- Element set: GSFC-003
- Inclination: 56.9857 deg
- RA of node: 213.2731 deg Space Shuttle Flight STS-60
- Eccentricity: 0.0008535 Keplerian Elements
- Arg of perigee: 263.0773 deg
- Mean anomaly: 96.9324 deg
- Mean motion: 15.72145611 rev/day Semi-major Axis: 6730.8981 Km
- Decay rate: 0.20E-05 rev/day*2 Apogee Alt: 358.25 Km
- Epoch rev: 11 Perigee Alt: 346.77 Km
-
-
- NOTE - This element set is based on NORAD element set # 003.
- The spacecraft has been propagated to the next ascending
- node, and the orbit number has been adjusted to bring it
- into agreement with the NASA numbering convention.
-
-
- Submitted by Frank H. Bauer, KA3HDO, for the SAREX Working Group
-
- /EX
-
- ------------------------------
-
- Date: Fri, 4 Feb 94 23:05:23 GMT
- From: agate!howland.reston.ans.net!newsserver.jvnc.net!a3bee2.radnet.com!cyphyn!randy@network.ucsd.edu
- Subject: simple ohm meter
- To: info-hams@ucsd.edu
-
- The hardest part is redoing the meter scale, so we'll show that first
-
- METER SCALE for ohms
-
- 0 - 15 original scale on the meter it self, meter being a 50 ua to 1ma job
-
- ohms
-
- 0 = 0 Scale changing:
- 1 = o.7
- 2 = 1.47 To get K ohms, change R1 to be 1 k
- 3 = 2.5
- 4 = 3.65 To get 100's K ohms change R1 to be 100k
- 5 = 5 and use a 9 volt battery, and meter to
- 6 = 6.7 be a 50 or 100ua job
- 7 = 8.8
- midscale = 10 *
- 8 = 12.5
- 9 = 15
- 10= 20
- 11= 27.5
- 12= 40
- 13= 68
- 14= 145
- 15= infinity
- * Same as R1
- ckt to use:
- R1
- o------+-----/\/\/------o 1.5 vdc ( or 9v if R1 is over 1k)
- | 10 ohms +
- test | + \-------or as in scale change
- +-/\/\--(/)---+
- R2 meter |
- | -
- o--------------------+--o
-
- R2...adj so meter reads infinity with open ckt at test
-
- That can be your 'OHMS ADJUST' .... you will also need an on off switch
- to not run down the battery, when not in use.
-
- This ckt...as shown for reading LOW ohms, is one WB1FNA ( silent key )
- used to bring along on ham fests to on-the-spot check out transformers and
- tube filaments!
-
-
- --
- Randy KA1UNW If you get a shock while
- servicing your equipment, "Works for me!"
- randy@192.153.4.200 DON'T JUMP! -Pete Keyes
- You might break an expensive tube!
-
- ------------------------------
-
- Date: 4 Feb 94 06:29:13 GMT
- From: ogicse!news.tek.com!cascade.ens.tek.com!not-for-mail@network.ucsd.edu
- To: info-hams@ucsd.edu
-
- References <2i8rnf$o5n@explorer.clark.net>, <CKM79r.45H@sunsrvr6.cci.com>, <2ire53$o2g@explorer.clark.net>░
- Subject : Re: Vertical Antennas
-
-
- At the risk of starting a flame war...
-
- In article <2ip6he$933@cascade.ens.tek.com> t1terryb@cascade.ens.tek.com (Terry Burge) writes:
- >>Just for the record, I will state it again. A ground plane antenna has higher
- >>gain than a vertical dipole. A quarter wave ground plane has a gain of some-
- >>where around 6 db over isotropic where a dipole has a gain of 2.14 db over
- >>isotropic at it's theoritical best. Gain in an antenna is directly related
- >>to it's RF pattern. I believe the reason a ground plane has more gain than
- >>a vertical dipole is because it has a more concentraited pattern like an
- >>elongated tear drop as opposed to the fat donut shape of a dipole.
-
- >Repeating false statements makes them no less false. A 1/4 wave vertical
- >over a *perfect* groundplane has *exactly* the same gain and pattern as
- >a 1/2 wave vertical. But alas, there are no perfect groundplanes in the
- >real world, so all real 1/4 wave verticals have less gain than 1/2 wave
- >verticals because of losses in the imperfect current mirror.
-
- >> As to weather an R5 or R7 are vetical dipoles or half wave verticals,
- >>I am no expert on them. I have never used one. But from everything I have
- >>read about vertical antennas, they must have a ground plane to mimic the
- >>other have of the antenna. Some systems utilize the shield of the coax cut
- >>to a certain length to do this I believe...seems some VHF/UHF antennas lend
- >>themselves to this. Other than that, ground rods would help as would sea water
- >>too.
-
- >A 1/2 wave antenna, it doesn't matter if it's fed in the middle or from
- >the end, doesn't require a current mirror, so it doesn't require a groundplane
- >or any other connection to ground. It's a resonant structure by itself,
- >there is no "other half" required. On the other hand, a 1/4 wave vertical
- >is self-resonant at *twice* the design frequency in the absence of a current
- >mirroring groundplane. So it must have a groundplane to function as a 1/4
- >wave vertical antenna at the design frequency.
-
- >> It is true that a half wave vertical has more gain than a 1/4 wave
- >>vertical.
-
- >What? You just stated otherwise above. Make up your mind.
-
- No I didn't, I said Half Wave Vertical, not dipole. You are the one who said
- there is no differance in gain weather it is fed in the middle or at the end.
- Let me state it again...for vertical antennas, a half wave vertical has more
- gain than a quarter wave vertical, a 5/8 wave has more gain still, a 3/4 wave
- has more yet, and so on...But how does the gain change if fed from the center
- or off center like a Zepp (don't I remember something about them having a gain
- of 1.66 over a dipole or something like that...probably wrong).
-
- But, we have to remember for a vertical antenna at given frequency, as the length
- of the radiating element increases the angle of radiation rises. And since it is such
- a theoretical nightmare to compute real world RF patterns we talk about theoretical
- perfect situations over perfect grounds and then compare those to the real world ones
- in the ARRL Antenna Handbook and other such material. I don't know too many Hams who
- can setup an acre of land with 120 radials spaced equaly around in a circle, seed the
- ground with the proper amound of rock salt, and do the rest to make as perfect of
- ground as possible (this is suppose to work for Yagi/Quad beams on towers too). Wish
- I had the place to do this...or is it 100 acres?
-
- >>It is not true that a 5/8 wave vertical is the highest gain vertical.
- >>What it is is the best compromise for the gain and angle of radiation. As the
- >>vertical element, or any element for that matter, gets longer for a given
- >>wavelength the major lobe/lobes eminating from the antenna start skeewing(sp)
- >>towards the far end of the antenna. This is why long wire antennas several wave
- >>length long at a given frequency are directional antennas. And, why Rhombic
- >>antennas are a combination of this characteristic.
-
- >Well that's almost true anyway. The 5/8 wave vertical over real
- >ground has the best gain perpendicular to it's axis of any *simple*
- >vertical antenna. Stacked and phased sections can have more gain
- >toward the horizon. Really long antennas develop minor lobes and
- >have their power directed in multiple undesired directions.
- Gary
-
- Gary, I agree that stacked dipoles develope more gain than single ones. And
- their radiation pattern is perpendicular to the direction they are setup,
- normally in a vertical configuration although I believe a collinear array
- is an example of horizontally polarized broadside dipole array with stubs
- to bring their patterns into phase and combine to make a higher gain signal.
- (now how is that for a run on sentence). But, on page 8-32 of the 1991 ARRL
- Antenna Handbook they list the theoretical power gain of various 1/2 wavelength
- collinear arrays...
- ' 2 collinear elements---1.6 db
- 3 collinear elements---3.1 db
- 4 collinear elements---4.2 db '
- ARRL Antenna Handbook, 16th Edition
-
- On page 8-24 of the same book is listed a 3 element, 1/4 wavelength vertical array in a line,
- 1/2 wavelength appart, each being fed with 3/4 wavelength coax phasing line to bring them into
- phase. It is not clear weather this is a broadside of end fire (think that is the correct term)
- array. Gain figures are states as follows...
-
- ' If the element currents are equal, the resulting pattern has a foward gain of 5.7 db
- (for lossless elements) ... If the currents are tapered in a binomial coefficient 1:2:1 ratio
- (twice the current in the center element as the two end elements), the gain drops to 5.2 db, the
- main lobes widen, and the side lobes disappear. ... '
- ARRL Antenna Handbook, 16th Edition
-
-
- This seems to indicate that it is possible to get more gain from 1/4 wavelength verticals than
- from 1/2 wavelength elements in a vertical or horizontal pattern. Hum... I would be the first to
- admit antenna theory makes my head spin sometimes but when the ARRL says a 4 element horizontal
- colliniear array has less gain that a 3 element 1/4 wave vertical array, I tend to believe it. I
- may not understand all the wherefores and as such but I tend to believe them.
-
- On page 2-23 of the same text...
- ' ...An infinitely thin 1/2 wavelength dipole has a theoretical gain of 2.14 db
- over an isotropic radiator (dBi)... '
- ARRL Antenna Handbook, 16th Edition
- And I know that the thinner the dipole the higher the Q of the resonant circuit, so an "infinitely
- thin" dipole has the highest Q. In other words, the highest gain. This is why a Quagi, quad driven
- element and reflector with dipole directors has more gain theoretically than a quad with the same
- boom length. (I have a love/hate relationship with quads) Higher Q elements.
-
- I haven't been able to find a gain figure for a single 1/4 wavelength vertical in the ARRL Antenna
- Handbook. Looking through the Amateur Radio Supply catolog(Winter 93/94) it is easy to see how gain
- figures vary.
- Having had some experience with Cushcraft antennas and believing they do their homework, I quote
- some of their specs...
- ' Four Pole Array ... (stacked dipole for VHF/UHF ranges)...
- AFM-4DA...144-148 (MHz)... Gain, dBd ... (over a dipole) ... 9 Offset(?)...6 Omni...'
- (page 107)
- (that is a 4 dipole stacked array with 6 db gain over a dipole...sounds like
- a bit of difference from the ARRL Handbook figures...4.2 db, so much
- for homework)
-
- On page 94 are the advertisments for the R5 and R7...
- ' R5...3dBi...17(feet)... R7...3dBi...22.5(feet)...(both)halfwave '
-
- On page 125 is the Butternut advertisment...
- ' ...HF-6VX...26(feet)... ' (no gain stated for their verticals)
-
- I have also had High Gain 18AVQ(WB)...almost worthless, and several home brew verticals like 1/4 wavelength
- 20 meter ground plane at 60 feet, a 5/8 wavelength 2 meter vertical ground plane, etc.
-
- Being I am a DX'er at heart I will take the Butternut and put up with the radials on my roof...perfect
- ground, 1/2 wavelength above ground, OR NOT! The one thing I can see the R5/R7 having over a Butternut is
- easy of setup. Of course, we could say the easier an antenna is to setup, the less effective it is. Terry's
- rule number 1 for Quad antennas (and maybe others too).
-
- Take it for what it is worth.
-
- Terry Burge
- KI7M
-
- 1983 CQWW Phone top W7, Single Op, All Band. (toot, toot)
-
-
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- End of Info-Hams Digest V94 #113
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