QRZ! Ham Radio 4/QRZ Ham Radio Callsign Database - Volume 4.iso/digests/antenna/940346.txt

Internet Message Format | 1994-11-13 | 26KB

Date: Sat, 15 Oct 94 04:30:09 PDT
From: Ham-Ant Mailing List and Newsgroup <[e-mail]>
Errors-To: [e-mail]
Reply-To: [e-mail]
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Subject: Ham-Ant Digest V94 #346
To: Ham-Ant


Ham-Ant Digest              Sat, 15 Oct 94       Volume 94 : Issue  346

Today's Topics:
                             6meter ant?
                         Antenna Rotor Wanted
                 Antennas are prohibited ...!!!!!!..
                     Enough already! I want 80m!
                              Is SWR it?
                    Military 225-400 band antenna
                                Quad's
                        Radio Shack Antennas?
                   Superior coaxial line? (2 msgs)
                       Tiger Tail (HT antenna)

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Archives of past issues of the Ham-Ant Digest are available
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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: 14 Oct 1994 02:24:06 -0400
From: [e-mail] (Sean1916)
Subject: 6meter ant?

In article <[e-mail]>,
<[e-mail]> writes:

I have 2 Mil surplus ground planes (tuneable)  centered in the 6meter band
they are field kits and will fold up e-mail me for more info

------------------------------

Date: 14 Oct 1994 14:43:18 GMT
From: [e-mail] (Val Breault)
Subject: Antenna Rotor Wanted

In article <edh.781812310@hpuerca> [e-mail] (Ed Humphries) writes:

   Can someone tell me what the windload rating is
   for the readily available Radio Shack antenna
   rotator? The local sales-droids don't even know
   what I'm talking about.

Hi Ed, I'm one of those sales-droids on weekends.  That information is not
available.  It's a light duty rotator that is adequate for it's intended
use (Radio Shack television antennas) but is not rated for other purposes.

You could try finding out who the real manufacturer is and asking them.
That would be the best way to go.  Alternatively, you could get the
Tandy Service Plan for an additional $20.  If the rotator fails within
three years the company will replace it under the terms of the TSP.
That solution lacks elegance, but it's easy.

I think it should be good enough for a small tribander.  I bought one
for that purpose but haven't gotten the tower up yet.

--
Val Breault - N8OEF - [e-mail]   \      /|
Instrumentation dept  GM NAO R&D Center   \    / |
My opinions are not necessarily those of   \  /__|
GMR nor of the General Motors Corporation   \/   |___

------------------------------

Date: Thu, 13 Oct 94 22:49:40 -0500
From: Priscilla Rutledge <[e-mail]>
Subject: Antennas are prohibited ...!!!!!!..

Just to provide the Devil's advocate, it is not just a pretty looking
neighborhood that we, your neighbors, want.  As you may have noticed,
most folks in late 20th century America make decisions based on perception,
rather than real risk.  I personally don't mind even a 20m antenna if
you don't let it get rusty and tumbledown.  What happens, though, is that
when I go to sell my house (and since so many of the people in my
association are military, 10-20% of them are on the market at any given time)
the eco-wimps ask worried questions about the "invisible rays" zapping
through the children's little bodies.  If they heard you use the phrase
"Radiation Pattern" they probably wouldn't move into the same county.
This foolishness can trim $10-15K off my final selling price.  True, it
is neither my foolishness nor yours, but I reserve the right to
from whatever "liberty" anyone chooses to take with it!

------------------------------

Date: 13 Oct 1994 09:06:32 -0700
From: [e-mail] (Terry Burge)
Subject: Enough already! I want 80m!

>>Greetings, all...
>>I have finally had enough of 20 and 40 meters, and am trying to come
>>up with a reasonable 80 performer for 80m. I live in an urban setting
>>with a small yard, and no practical access tothe front yard.  Vericals
>>are out of the question...no room for supports or guys. Certainly no
>>room for a dipole, nor do I have tall enough trees to get it a 1/4 wave
>>up.
>>
>
>
>Not to belabor the obvious, but in your post you DID say you wanted to
>work DX....  Under the circumstances given, you're much better off
>sticking with 20 and 40.  Antennas are smaller, radiation angle is
>lower, absorption in the ionosphere is less and that's where the DX
>hangs out anyway.  Ok, ok, there is some DX to be had on 80, but the
>guys you hear working it have humongous antennas - certainly not
>backyard-size loops at 30 feet.  Antennas are fun to play with, but if
>it's DX you're after, etc, etc.
>
>I can almost hear the keyboards springing to life across the country
>with tales of how they worked so-and-so with such-and-such, but the laws
>of physics will have the last word, as usual.  Do what you like, Sean,
>but don't get too disappointed.  There ARE reasons why 20 and 40 are so
>popular.
>
>

Laws of Physics....????
Everytime someone works another person with 100 watts and a small vertical
or dipole at low height the 'laws of physics' are stepped on. Sure, the
big boys on 80 meters run big antennas...2,3, 4 element beams, 4 squares,
etc. but some also work with dipoles and compromise verticals. And they
still make contacts. They don't hear as well a the bigger antenna setups,
but then they learn to sharpen there skills and pull out the weaks ones
anyway. IF you stick with it it's not that hard to work 100 countries on
80 meters. It just takes time, patience(sp) and doing the best you can
with your location's conditions.

Why not put up the best vertical you can..45 foot or so, match it up with
a tuning arrangement, and go to work on it around 3800 Khz. That is less
of a compromise antenna than my Butternut HF6V at 26 feet and I still
manage to work Europe every once in awhile. Not an easy thing from the
west coast.

Also, with CQWWDX contest comming up a a couple of weeks, not to mention
the other contests, you will find lots of DX on 80 meters...and 20, 40,
160, etc.

And don't worry about the 'Laws of Physics'. They will take care of them-
selves and you will still manage to work some DX. Enjoy.

Terry,
KI7M


------------------------------

Date: 14 Oct 1994 16:36:22 GMT
From: [e-mail]
Subject: Is SWR it?

In article <37kuvb$[e-mail]>,
Sean Lester <[e-mail]> wrote:
>If you match your antenna imedance with your transmition line and
>transmitter, then get your SWR down to < 1.2:1, do I have to worry
>about anything else for VHF?

Hi Sean, what kind of coax did you use and how long is your transmission
line. You will lose more than half of your power as heat in 100 ft of
RG-58 on 146 MHz.
--
73, Cecil, KG7BK, OOTC   (All my own personal fuzzy logic, not Intel's)

------------------------------

Date: Fri, 14 Oct 94 09:46:37 EDT
From: [e-mail] (Jim Grubs, W8GRT)
Subject: Military 225-400 band antenna

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[e-mail] (JudithG560) writes:

> In article <[e-mail]>, [e-mail]
> (JACK HIRSCHBERG) writes:
>
>    For such very-wideband reception (or transmission) use a discone.  It
> has no gain over a 1/4 wave ground plane, but it has extreme bandwidth.
> This is why you will see them in use at all military airfields.

And for mobile use, mount them upside down on the roof.

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--
[e-mail]

... I'm not politically incorrect; you're ideologically sheltered.

------------------------------

Date: Thu, 13 Oct 1994 17:43:15 GMT
From: [e-mail] (Russ Renaud)
Subject: Quad's

In a previous article, [e-mail] (Lynn Geitgey  KB0LRB) says:

>The other day, while browsing several Antenna books, I came across an
>interesting, but unexplained idea.  Is there some Quad Guru out there,
>who can explain the reasoning behind locating the feed point for a Quad
>in a corner, instead of the middle of a loop?  I understand the positioning
>of the feed point, on the bottom, for Horizontal polorization.  An on the
>side, for Verticle Polorization.
>
>What advantage/disadvantage's are there to the feed point being in a corner?

Well, it wouldn't get quite so loaded with freezing rain, if you happen to
live in an area where that occurs.

I don't think there's a significant difference in the impedance at
resonance, which is something that I've been trying to determine.  Mininec
just doesn't seem to model quads all that well, at least for determining
impedance.

73 de va3rr/aa8lu

------------------------------

Date: Wed, 12 Oct 1994 23:34:00 GMT
From: [e-mail] (Clint Bradford)
Subject: Radio Shack Antennas?

D>Path: planet!isdnlin.mtsu.edu!darwin.sura.net!jabba.ess.harris.com!news.ess.h
 >From: [e-mail] (Mike Basinger)

D>I'm thinking about buy an car antenna for my HTX-202. Are the antennas
 >they sell at Radio Shack any good, or are they basically junk?

No, they are not basically junk. But MFJ makes a great 2M mag mount for
under 20 bucks that is tuned for you already!

---
 * QMPro 1.53 * Useless laws weaken the necessary laws.

------------------------------

Date: 14 Oct 1994 18:12:43 GMT
From: [e-mail] (Roy W Lewallen)
Subject: Superior coaxial line?

[e-mail] (Curtis Wheeler):

>Loss is loss, a decibel is a decibel, whether transmitting or receiving.

Technically, this is true. But at HF, many decibels can be lost on the
receiving end without any impact on the signal/noise ratio, while a dB
lost on the transmitting end will result in a 1 dB decrease in the
signal/noise ratio. This is because the majority of the system noise is
caused by the atmosphere and other sources between the transmitting
and receiving antennas. At VHF and UHF, the noise of the receiver
dominates, and a dB loss at either end will result in a dB reduction
in signal/noise ratio.

Roy Lewallen, W7EL
[e-mail]

------------------------------

Date: 14 Oct 1994 15:57:32 -0400
From: [e-mail] (David M. Roseman)
Subject: Superior coaxial line?

>>
>>One can even get this coax for free by visiting ones local cable TV provider.
>>Ask them if they have any leftover chunks from the giant spools they use. Ive
>>gotten some nice sections (as much as 100feet) this way. The connectors for
>>Heliax are, however, more valuable than gold.
>>

ok..now is it the cable COMPANY...or just any TV station???


DAvid
|-----------------------------------------------------------------------|
|         David Roseman       |          [e-mail]                |
|      SysOp of NODE 3 BBS    |          The Flying HAm - BBS           |
|     Running OBV/2 Software  |          KBR-9318 - CB                  |
|                             |          N3SQE/SVARC - Ham              |
|         HAmmy in IRC        |  [e-mail] - Packet  |
|-----------------------------------------------------------------------|

------------------------------

Date: Fri, 14 Oct 94 02:33:00 GMT
From: [e-mail] (Steven M. Palm)
Subject: Tiger Tail (HT antenna)

In article <[e-mail]> [e-mail] writes:
>
>[e-mail] (Bob Levine) writes:
>>I discovered that in the plane of the HT (my FT530), the signal strength
>>is greatly increased with the TT.(>2x)
>
>Oh, my, 3dB+?  Wow.
>
>On the other hand, if people will pay $7.95 for it, then
>that's what it's worth.

 One thing that is worth mentioning....

 I had posted earlier that my HTX-202 HT did not like an aftermarket
 ICE Icom BP-8 compatible pack.  After much playing around we found
 out that it was allowing RF back into the radio and triggering the
 Er2 PLL Unlocked error.

 After reading the discussions here on the Tiger Tail, I decided to
 cut a hunk of wire about 19", and hang it off the BNC connector.  I
 hooked up the ICE pack and COULD NOT DUPLICATE the Er2 code.  If I
 removed the wire, it would be right back when it had a ground plane
 (i.e. up against my body or on a metal surface).

 So....  I feel better, being able to use my new battery, and also
 think that the Tiger Tail might have some use after all. :)

------------------------------

Date: 14 Oct 1994 11:01:24 -0700
From: [e-mail] (Jim Garver)

References<[e-mail]> <37jlu8$[e-mail]>, <[e-mail]>
Subject: Re: Enough already! I want 80m!


I just installed a full size 80 meter 1/4 wave vertical up the side of
one of my trees.  Its 60 some feet tall and hangs off the side of the
main trunk of a Cedar tree 2-3 feet out.  I began laying down radials
while observing the feedpoint with a noise bridge.  Two radials more
than 1/4 wavelength long opposite each other showed about 150 ohms.
When I added a third radial perpendicular to the others the impedance
dropped below 50 ohms where it has stayed since I've added more radials.
I plan on adding radials until I see no improvement.  They are just small
gauge wires laying on top of the ground.  The antenna itself is made out
of 3/4" CATV hardline using the aluminum jacket as the element.
Mr. Moxon and maybe others believe that tree absorbtion from close
vertical elements is very high but my experiments indicate differently.
I used to have a full size 80 meter dipole 60 feet high and feed with
ladder line to a Johnson Matchbox.  I also had some old coax running up
a tree so I shortened it until it resonated about 3800 kc.  A wire fence
under the tree was used for ground and counterpoise.  Comparison between
the two antennas showed that almost all signals were at least a couple
of S units down on the vertical.  All except the DX which was slightly
stronger on the vertical.  The best part was that local noise from the
nearby city was severely attenuated on the vertical as well.  All those
neon sign transformers, motor brushes, power poles, etc. were way down.

DX big guns in the 3790-3800 window talk about working long or short
path so they must be using steerable arrays.  I can hear some of the
DX they are working but can't hear others.  VK, JA, are no problem for me
here on the West Coast.  Some nites are very noisy and others rather
quiet just like the dipole used to be.  The 80 meter vertical also seems
to receive well on 160 meters, the BC band and LF.  I plan on adding
remote switched base coils for some of these freqs or maybe a motor
driven roller inductor.
--
[e-mail]  WA7LDV    "Each day is like a crisp new dollar bill.
I speak only for myself.            How will you spend it?" - Barnaby Jones

------------------------------

Date: 14 Oct 94 15:52:41 GMT
From: [e-mail] (Chuck Hawley)

References<378j3a$[e-mail]> <[e-mail]>, <37je9l$[e-mail]>
Subject: Re: Enough already! I want 80m!

[e-mail] (Sean E. Kutzko) writes:


>In a previous article, [e-mail] (Robert Adams) says:

>>>Sean E. Kutzko KF9PL ([e-mail]) wrote:
>>>
>>>: Honestly, I want a DX performer for a SMALL city lot. Knowing that this
>>>: is a HUGE order to ask for with the limited space I have, I got to thinking
>>
>>It's more than a "HUGE" order... it's more than facetious, too.


>facetious (fe-SEE-shus) adj. Joking or trying to be jocular, especially at
>an inappropriate time.


>I'm not joking. And, actually, I take offense to your statement.

Getting on HF, especially 80M, requires more than just an antenna. It
requires developing some kind of attitude that "takes it all in stride".
I enjoy very much the hams on HF, but I wouldn't want to live with 99.99%
of them. When the remarks lead off the subject of what I want to talk abt
or learn abt, then I usually try to talk right thru it as if it didn't
happen. I think that's very effective....and I get what I want. Sometimes
I have to just give up for the nite...if the racial, religious, male
chauvinist, or potty mouth stuff gets going and I can't redirect the
conversation. Same goes for the "No Balun" or "No Tuner" absolutists.

>I know I'm not going to get the performance of beverages and a 120' vertical
>resonater. Give me a break!

>Thanks to all of you who submitted some good ideas to me via e-mail.

I use a full wave loop on 80M and above. It's horizontal and takes 3
mounting points. I feed it where it's convenient to the shack. It fits
into an 85 foot square space, mostly over the house. I think it's about
the best compromise for small lots, and it works very well. Any normal
nite, I can be q5 in California or Haiti on 100 watts on 80M. I think
it's better than the local cloud warmer they say it is.


>Sean Kutzko KF9PL
>Urbana, IL




Chuck Hawley, KE9UW in Urbana, Illinois
[e-mail]
School of Chemical Sciences, Electronic Services
University of Illinois, Urbana-Champaign

------------------------------

Date: Wed, 12 Oct 1994 18:04:23 +0000
From: [e-mail] (Ian G3SEK)

References<[e-mail]> <373266$[e-mail]>, <[e-mail]>
Reply-To: [e-mail]
Subject: Re: Yagis w/variable polarization

In article: <[e-mail]>  [e-mail] (Zack Lau (KH6CP)) writes:

> Have you used your array for long distance troposcattering?
> I wonder if there is a significant advantage to being able to
> rotate the array's polarization?  In other words, over paths
> greater than 600 km, do you see significant polarization rotation?
> I normally run QRP, so even 600 km is a long path for me :-).

Sorry, no. The antenna is down close to the ground, so that it's easier
to work on, less obtrusive when not in use, and can operate in stronger
winds. As far as I know, troposcatter doesn't cause significant polarization
rotation, but you should check that with K1FO and NC1I who have higher-
mounted arrays than I do.

> If an East Coast USA station were putting up a fixed polarization
> array to work Europe on 432 EME, what would be the preferred
> polarization?

It depends on the combination of Faraday rotation, the approximately 90deg
polarization rotation caused by the longitude difference, and the E-W
position of the moon. You can predict and plan for the last two, but not
Faraday rotation, so there isn't a simple answer I'm afraid. A few years ago
K1FO researched the possibility of making skeds at times when the geometrical
(longitude and moon position) factors combine to make the rotation either
zero or 90deg, but I think the only conclusion he reached was to install
rotatable polarization!

It isn't very difficult to make a small EME array with polarization rotation.
Two long yagis mounted at opposite ends of a cross-boom can be pivoted at the
center of the boom and made to swing between vertical and almost horizontal
polarization before they come close to the mast or tower. You can steer the
array by hand every 20 minutes or so, but polarization must be rotatable from
the shack - a small TV rotator will do it.

> I've heard that there are a couple of big European
> stations that can be worked [on 432], even if you can't hear your own
> echoes.

More than a couple! 2m isn't the only band with 'big guns' who are workable
using a small system. At moonrise you should be able to hear SM4IVE (40ft dish,
switchable polarization) and also DL9KR with a single long yagi and GaAsFET
preamp. If you can work VE3ONT, go looking for those two as well.
Not far behind are F5ELL, F5FHI, F6HYE, DL9EBL, SM2CEW and several others.
With an array that can track the moon in elevation, you can avoid the moonrise
'rush hour' and have plenty of time to work these stations.


**************************

Now here's a question for you, Zack, since you've used more GaAsFETs than
most people.

How do you tell which are which then they're mixed-up on the bench?
(A friend bought me some MGF1302s for me, but many different devices
come in the same type of anonymous anti-static packaging, and he isn't
sure which ones are my 1302s any more.) Do the one-letter or two-letter codes
marked on the devices mean anything outside of the factory?



 73 from Ian G3SEK               |  Editor,  _The_VHF/UHF_DX_Book_
 Abingdon, England               |
 [e-mail]       | "In Practice" columnist for RadCom (RSGB)

------------------------------

Date: 14 Oct 1994 15:13:32 GMT
From: [e-mail] (Kim Elmore)

References<36q6d6$s60$[e-mail]> <[e-mail]>, <[e-mail]>
Subject: Re: Antennas are prohibited ...!!!!!!..

In article <[e-mail]> Priscilla Rutledge <[e-mail]> writes:

    <snip>

>you don't let it get rusty and tumbledown.  What happens, though, is that
>when I go to sell my house (and since so many of the people in my
>association are military, 10-20% of them are on the market at any given time)
>the eco-wimps ask worried questions about the "invisible rays" zapping
>through the children's little bodies.  If they heard you use the phrase
>"Radiation Pattern" they probably wouldn't move into the same county.
>This foolishness can trim $10-15K off my final selling price.  True, it

    It is a shame that we, as amateurs, play into the hands of our
opponents so easily.  As part of a battle to lift undue restriction on
amateur antenna installation in Boulder County (which, alas, was
unsuccessful) We performaed a matched-pairs analysis to see if
proximity to tall (greater than 60 ft) amateur towers affected prices
for homes near them (next door to 3 or 4 houses away).

    At whatever confidence interval we chose, the answer was "no".
We also examined if the presence of amateur towers affected the length
of time a home was on the market.  Again, the answer was "no".

    This is not to say that there are certain people for whom
amateur tower installations are deeply offensive, but their number
appears small enough that it does not affect either the selling price
of homes or their length of time on market, to any noticeable degree.

    At first blush, such arguments as decreased property values
seem compelling but then the concept of an "Ether" through which radio
waves propagated seemed compelling, too.  Neither one is correct.


            Kim Elmore, [N5OP, PP ASEL/Glider 2232456]
*  _._. __._ _.. _.._ _.. . _. ..... ___ .__. _. ..... ___ .__. _.. _.._ _._  *
*    Said by NQ0I while working on his shack:                                 *
*        "All these *wires*!  Why do they call it `wireless'!?"        *
*  _._. __._ _.. _.._ _.. . _. ..... ___ .__. _. ..... ___ .__. _.. _.._ _._  *

------------------------------

Date: 14 Oct 1994 10:33:53 -0400
From: [e-mail] (Andy Domonkos)

References<378j3a$[e-mail]> <[e-mail]>, <37jlu8$[e-mail]>
Subject: Re: Enough already! I want 80m!

In article <37jlu8$[e-mail]>, Terry Burge wrote:
>
> Laws of Physics....????
> Everytime someone works another person with 100 watts and a small vertical
> or dipole at low height the 'laws of physics' are stepped on. Sure, the
> big boys on 80 meters run big antennas...2,3, 4 element beams, 4 squares,
> etc. but some also work with dipoles and compromise verticals. And they
> still make contacts. They don't hear as well a the bigger antenna setups,
> but then they learn to sharpen there skills and pull out the weaks ones
> anyway. IF you stick with it it's not that hard to work 100 countries on
> 80 meters. It just takes time, patience(sp) and doing the best you can
> with your location's conditions.
>
> Why not put up the best vertical you can..45 foot or so, match it up with
> a tuning arrangement, and go to work on it around 3800 Khz. That is less
> of a compromise antenna than my Butternut HF6V at 26 feet and I still
> manage to work Europe every once in awhile. Not an easy thing from the
> west coast.
>
> Also, with CQWWDX contest comming up a a couple of weeks, not to mention
> the other contests, you will find lots of DX on 80 meters...and 20, 40,
> 160, etc.
>
> And don't worry about the 'Laws of Physics'. They will take care of them-
> selves and you will still manage to work some DX. Enjoy.
>
> Terry,
> KI7M
>
>
>
A local ham here in Maryland put a Hustler 80M mobile antenna in his attic with
2 counter poises and he had excellent results, considering the size/reduced
bandwidth. The extra height above ground (about 20 feet) for the feed point
makes a BIG difference.

Andy N3LCW

------------------------------

End of Ham-Ant Digest V94 #346
******************************