On Jun 17, 2009, at 6:44 AM, towertalk-request@contesting.com wrote:
> I didn't mean to be a PITA, but I was running for the airport when I
> typed
> that reply and wanted to give you a fast response that was right
The short, the "RTFM" answer struck me the wrong way since I was
trying to learn from others. Especially after a long day here, too, so
I apologize for my snippy reply. BTW, thanks for taking the time to
reply.
As I interpret the conventional wisdom of ground effect on antennas,
according to the ARRL antenna book and ON4UN's "Low Band DXing", the
theory is that an antenna low enough to the ground will result in
ground losses except under perfect ground, which can be man-made
(counterpoise) or natural (if you're lucky enough). In my mind, adding
a ground screen under that corner should reduces ground loses. Of
course, how much in negligible. In L.B. Cebik's paper on NVIS loops
with ground screen there is a bit more gain with a ground screen. But
the size of the ground screen, 1 wavelength x 1 wavelength is really
big for my space - actually impossible.
Also, on a related note, since I'm using a antenna coupler (Icom AH-4)
and 210' of wire, as the antenna is "tuned" (for lack of a better
phrase), does the wavelength of counterpoise change also? Since the
coupler matches the impedance for the antenna, do the parameters on
the counterpoise change, also? This is straying from the loop
configuration, but is more of a question using a vertical and
counterpoise situation. My thought process is to build a counterpoise
under the vertical to match the wavelength of the wire (whatever
length) for the best results.
Any thoughts?
73,
Jeff
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