I really did not plan to respond to this thread, but after seeing Charlies'
comments, I thought I should share my experiences, as they may be of help
to others here.
In 2004 I constructed a 1/4 wl 80 meter ground plane antenna, and installed
a 3/16 wl radius screen on the ground under it. The screen was made up of a
grid of #14 copper wires, with 36 inch spacing, bonded with plumbers
solder at each and every grid crossing point. On top of this grid I also
installed 32 equally spaced 1/4 wl radials.
A second 80 meter ground plane antenna was constructed several hundred feet
away (this was to be the first of my 4-square array). This antenna was
constructed with the base raised 10 feet off the ground, and 3 elevated
radials were installed parallel to the ground so that grazing cattle could
move about freely without doing damage. The radials were made about 10
percent shorter then a quarter wavelength, tied together at the base of the
vertical, and the antenna was then brought to resonance by placing a single
coil between the radials and the coax shield connect point.
I was able to select either of the verticals with an A-B switch at the
operating position. I ran this system for an entire season, running
comparisons on both receive and transmit, and relying on DX stations to
give me comparative readings when I would switch antennas. My experience is
this: On receive I could tell very little difference (if any) between the
antennas. On transmit, I would often get better reports on the elevated
ground plane. This was very surprising to me, as I had always heard that
more radials make a better (read better for DX) antenna, and that the
elevated system should produce a signal strength of up to 6 db lower then a
well constructed radial system would have. I never got a better report on
the ground mounted antenna, but on a lot of occasions the listening
stations would say the signal strengths of both antennas were identical. My
conclusion was that I should go with the elevated radial system. I did this
for both my 80 meter and 160 meter 4-square systems. The 160 system uses 4
radials per antenna, and these are 20 feet high and parallel to the ground.
John, ON4UN, claims I now have a great dummy load on 160, hi. But its
working for me.
Soil conditions undoubtedly have something to do with it. I live in
Northeast Texas, and we have hardwood trees and grazing land here with a
lot of iron in our red clay like soil, together with sand (I'm about 40
miles south of the Red river, guess where it got its name). W7IUV has had
just the opposite results from mine as far as antenna performance is
concerned. Larry claims his system is a poor performer. He is in western
Washington with desert like soil conditions.
My final comment is this: the only way to really know which is best for
you and your location, is to build both systems and run the comparison
tests over a full season, like I did. I will make no claim of one type
being superior to the other. It all depends....
73, Dave - W5UN w5un@wt.net
homepage: http://web.wt.net/~w5un Grid: EM23mg
2356 County Road 3245
Mount Pleasant, TX 75455
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