[Elecraft] Windom Antennas

Fri Jun 6 19:48:00 2003

George:
  I'd sure like to know how you are feeding those EDZs.

best wishes,

dave belsley, w1euy

--On Friday, June 6, 2003 5:36 PM -0500 "George,  W5YR" <[email protected]> 
wrote:

> Guy, you must have had some adverse experiences with verticals somewhere
> along the line . . .
>
> I use the Butternut HF-9V, ground mounted over a field of 18 radials each
> 25 ft long. The antenna resonates per the CIA-HF impedance instrument in
> each of the 9 bands. It loads well with very low line SWR. Based upon the
> SWR, impedance measurements and the design of the radial field, the total
> ground loss is likely no greater than 3 dB and is possibly less. This is
> in a typical backyard with trees, power pole and lines nearby, etc.
>
> The key thing about the vertical is that in competition with a pair of
> 20-meter extended double zepps, mounted at 38 ft and at 90 deg,  and a low
> 80-meter horizontal full-wave loop, the vertical many times produces
> better signals than any of the other wire antennas.
>
> I participate in the QRP-L Fox Hunts and most QRP operating events and
> fully a third of  the time, the most difficult contacts are made with the
> vertical.
>
> I find that it is noisier than the wires but not exceptionally so. Late at
> night when 20 meters is largely asleep, it is interesting to monitor
> 14,100 and listen to the beacon stations and try the various antennas.
> You would be surprised at how often the vertical returns the best signal,
> even from locations favored by the patterns of the EDZs.
>
> All your points are technically valid, and taken in summation would
> persuade anyone that using a vertical is heresy. Nonetheless, with proper
> installation and attention to the points you mentioned, a vertical - even
> a "compromise" multi-band vertical - can provide superior performance when
> conditions favor.
>
> You might enjoy reading of the research done in the 70's with shortened
> verticals by Jerry Sevick, W2FMI. His work was published in QST at the
> time and is reprinted in appendices in "Building and Using Baluns and
> Ununs."
>
>  Jerry provides quite detailed loss measurements and the like for various
> radial configurations, etc. I might add that Dr. Sevick, formerly a
> scientist at Bell Labs, knows what he is doing, and his work can be relied
> upon for accuracy.
>
> Neither his work nor my experience and measurements can support your dire
> predictions of 6-10 dB loss with a vertical for the reasons you enumerate.
>
> 73/72, George
> Amateur Radio W5YR -  the Yellow Rose of Texas
> Fairview, TX 30 mi NE of Dallas in Collin county EM13QE
> "In the 57th year and it just keeps getting better!"
> <mailto:[email protected]>
>
>
>
>
>
> ----- Original Message -----
> From: "Guy Olinger, K2AV" <[email protected]>
> To: "Bob Lewis AA4PB" <[email protected]>; "Elecraft"
> <[email protected]>
> Sent: Friday, June 06, 2003 5:00 PM
> Subject: Re: [Elecraft] Windom Antennas
>
>
>> I agree with your statement about poor installation. Unfortunately it's
> quite WORSE than that. Lack of a proper ground connection is only loss
> factor #1. Note that poor series ground conductivity at a ground located
> feedpoint does not apply to a series of "vertical" antennas that have feed
> points up the antenna. But the rest below DO.
>>
>> Loss factor #2:
>>
>> An antenna will initially radiate about half its power below the horizon.
> Horizontally polarized energy will essentially bounce at some angle, at
> full strength.
>>
>> Vertically polarized energy will usually be absorbed instead of bouncing.
> UNLESS the ground media at the bounce is salt water or laced with
> conductors, like extensive dense buried radials. Both of those are rare in
> the typical installation, since the vertical was chosen because of LACK of
> good supports for horizontal antennas, or limited space, which means
> limited space to place radials, if even practically possible.
>>
>> Loss factor #3:
>>
>> A vertical antenna has a lot of flux directly underneath. It penetrates
> the ground to a surprising degree. If there is not a conductive dense
> screen underneath (even for the "center fed models" not using the ground
> as a current sink) the flux penetration of the ground will induce loss
> currents in the area immediately underneath. This loss is completely
> independent of any "ground connection" on the vertical.
>>
>> Loss factor #4:
>>
>> High current losses due to compromise tuning for multibanding, shortening
> for convenience in construction can occur at aluminum joints, traps, and
> in miscellaneous connections in the antenna.
>>
>> Loss factor #5:
>>
>> Trees, buildings, etc in the vicinity will all attenuated a vertical
> signal to a higher degree than horizontal signals. This is especially true
> at the low angles we are targeting in the first place.
>>
>> It's important to remember in this thread that the original post had to
>> do
> with a very limited installation of a compromise multiband vertical
> antenna, not a W8JI ultimate vertical paradise.
>>
>> IF the owner has the time and inclination to do some work with radials
>> and
> specifically go after the loss factors, then some considerable success can
> be had.
>>
>> UNFORTUNATELY, only a tiny percentage of the residential vertical
> installations I have seen had 1 through 5 above attended to. Most were
> significantly afflicted with these factors, initially not knowing what was
> happening to them, and even a LOW horizontal antenna improved their
> results dramatically.
>>
>> If one is going to do the "vertical" thing, DO the ***ENTIRE*** vertical
> thing, or don't bother. Don't just stand the thing up, run coax to it, and
> think you are done. This is particularly true for the QRP crowd, where the
> 6-10 db disadvantage you can accumulate in factors 1-5 isn't there to give
> away in the first place.
>>
>> 73, Guy
>> K2AV
>>
>> >
>> > From: "Bob Lewis (AA4PB)" <[email protected]>
>> > Date: 2003/06/06 Fri PM 04:40:35 EDT
>> > To: "Elecraft" <[email protected]>
>> > Subject: Re: [Elecraft] Windom Antennas
>> >
>> > > ...the joke about verticals is "radiate equally poorly in all
>> > directions".
>> >
>> > I think verticals get this "bad rap" because the typical ham doesn't
>> > install them correctly. No good radial or counterpoise system - shove
>> > an 8-foot rod in the ground and call it "grounded".  I wonder how well
>> > a dipole would perform if you only put up half of it.
>> >
>> > The bottom line - it's usually easier to put up a "good" horizontal
>> > antenna than it is to install a "good" vertical.
>> >
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>>
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>
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----------------------------------
David A. Belsley
Professor of Economics