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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