With respect to the claims below by Gap, the trick is that the "other"
antenna descriptions are not complete, either as to their size or
configuration. For instance, a base loaded 6 foot whip resonant on 40
meters, with a pipe driven into the ground as the shield connection,
qualifies as a "monoband vertical".
With respect to radials vs. counterpoise -- I've not heard anyone
describe or imply a "buried" counterpoise. However, I have heard many
refer to radials with a clear implication by context that they were
speaking of "elevated radials". Whether that violates some
terminology "rule" I will leave to others.
Part of reason some may use "radials" to describe a counterpoise may
be the difference between saying "30 radials" and saying "30 wire
counterpoise"
A counterpoise or "elevated radials" need to be resonant if a
non-reactive feed impedance is desired. This is not an issue for
buried radials, as the velocity factor is low whether insulated or
not.
There is extensive documentation in literature of the improvement in
performance up to roughly 60 buried quarter-wave radials, and more
controversially up to 30 or 60 elevated quarter wave radials.
Personally I own a Gap vertical, but I have no illusions about what it
is and is not. It's biggest use is listening on another band while
transmitting and being cross polarized and at some distance to the
main antennas to allow constant connection to the receiver.
73, Guy.
----- Original Message -----
From: "David L. Foreman" <davelf11@cox.net>
To: "KC7VDA" <KC7VDA@keepandbeararms.com>;
<antennaware@contesting.com>
Sent: Thursday, May 10, 2007 5:49 PM
Subject: Re: [Antennaware] radials
Good afternoon, Dan.
The Gap Challenger Multiband DX antenna that the OPRC has or had
available, uses three counter poise wires and from reading the manual,
and my emails with Gap, are buried just like radials, although you
could elevate them with the antenna.
The person the answered my email to Gap asked my why I wanted to
elevate the eitire antenna and counter poise system.
Below is what Gap says about the antenna.
Dave
KE7FZJ
+++++++++++++++++++++++++++++++++++++++++
CQ tested the Challenger and established that on 2m, for example, its
gain was approximately 6 to 8dB. On 40m compared to a mono band
vertical, they found Challenger an S unit stronger. This is typical of
the many reports received from amateurs around the world. Challenger
is designed to be mounted directly in the ground or elevated. A ground
mount is provided with each antenna. With the ground mount in place,
the Challenger simply drops in. If necessary, because of space
limitations, but not to improve performance, Challenger may be roof
mounted since it does not require earth loss to obtain a 50 ohm match.
Challenger requires a counter poise of three 25ft. insulated wires.
They may be buried or just scattered on the ground. Symmetrical
deployment is not critical. Adding additional wire will not
significantly improve performance. All of these are covered in a
16-page assembly manual provided with each antenna.
++++++++++++++++++++++++++++++++++++++++++++++++++++++
----- Original Message -----
From: "KC7VDA" <KC7VDA@keepandbeararms.com>
To: <antennaware@contesting.com>
Sent: Thursday, May 10, 2007 13:06
Subject: Re: [Antennaware] radials
>
> -----Original message-----
>> Today's Topics:
>> 1. Re: homemade coil (Andrew Ingraham)
>> ----------------------------------------------------------------------
> Hello All;
> If you will pardon a newcomer ( to your group) for poking his "
> beazer" into
> what appears to be an ongoing argument, an argument that I am sure
> will continue
> as long as there are Hams and antennas, I have a few questions and a
> comment
> or two.
>
> First a question and a comment, an unkown writter makes the
> statement:
>
>> > with poor reports, running 600 watts. I worked US hams at about
>> > 200
>> > miles with good reports. However, I think that I can lay much of
>> > the
>> > blame for the reports on the fact that I have a single radial,
>> > slightly
>> > shorter than 1/4-wavelength. Once I establish a good mechanical
>> > connection and a reasonable SWR, I will add radials (aiming for
>> > 60) and
>
> Does he really mean a radial or a counterpoise?
> if he really means a counterpoise, would the addition of radials
> really do any
> good? I am under the impression that radials were not needed where a
> counter-
> poise is used, that the counterpoise served the same perpose.
>
>> I have no personal experience with verticals (aside from
>> engineering at AM
>> radio stations long ago), but from what I've read elsewhere, even a
>> single
>> radial is OK *as long as it is not buried* or on/close to the
>> ground.
>
> I too have served my time working with AM stations, the vertical of
> my station
> was surrounded by 160 radials that, after the first few feet, were
> burried under
> egg sized rocks.
> However,when working with Ham Band verticals, I have been under the
> impression that a minimum of 4 radial, each 1/4 wave length of the
> lowest
> frequency to be used was a necessity. ( and yes, I understand that
> more is
> usually better, up to a certain point, ) Am I wrong about the length
> or does it
> matter ?
>
>> Elevated above ground, it's a counterpoise, you want it to be a
>> quarter
>> wavelength long, and you need only one (though having only one
>> might make
>> the antenna a little directional). But once it's coupled to the
>> ground, the
>> soil detunes it and ground losses go way up ... unless you've got a
>> lot of
>> them.
>
> My experience here in Tucson, Arizona has been that burying radials
> up to 4
> inches below ground doesn't make any difference, I belive that the
> dry nature
> of the local soil to be responsible for the low losses.
>
>> So to improve your signal, you could either run your single radial
>> elevated
>> above ground, or bury 60 of them.
>> The nice thing about buried radials, is that they can be shorter
>> (about 0.1
>> wavelength) and they don't need to be tuned.
>>
>> Regards,
>> Andy
>
> Yes, I fully agree, run as many radials as you can, make them as
> long as you possibly
> can, keep them, preferably, above ground but bury them if you must,
> and you will
> definitely improve your signal .
> To my way of thinking, the only thing that improves a good ( maybe a
> great ) antenna
> system is a good radial and ground system.
> My only other comment would be that the radials don't have to be run
> in a perfectly
> straight line, the wires composing your radial system can be moved
> around as needed
> to clear obstructions ( read that as your better halfs Roses, Mom's
> Petunias, the side-
> walk or Juniors swing set, sandbox etcettra) . If that obsticle is a
> beautiful yard full of
> grass that you are understandably reluctant to dig up, the solution
> is to beg, borrow or
> otherwise scrounge a side walk trimmer. With it you can easily make
> very nice, narrow,
> cuts in the grass, without any dirt being thrown up on the grass.
> You then simply stuff
> the radial wire into the cut you just made and when you next water
> the grass the cuts
> will disappear.
>
> O.K. thats my 2 bits worth, and should add a little more fuel to the
> fire, if I have said
> anything that you disagree with I am certain you will let me know
> and I look forward
> to hearing it.
>
> 73 de kc7vda (Dan)
>>
>>
>> ------------------------------
>>
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>> Antennaware@contesting.com
>> http://lists.contesting.com/mailman/listinfo/antennaware
>>
>>
>> End of Antennaware Digest, Vol 44, Issue 1
>> ******************************************
>>
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