[Antennas] Ground Planes

[Alex Eban]

...William made a very important point!!
	Actually what we call a ground plane can operate in one of 2 modes:
resonant and not resonant and the mechanism is fundamentally different in
each case.
	For the resonant mode, known as counterpoise, the length is
critical. However, one should remember that any non symmetrical layout of
radials will distord the radiation pattern of the antenna! Soo, if you
choose to use a few resonant radials only, be prepared to accept some
distortion in the radiation pattern.
The other mode, the true ground plane is relying on its capacitive coupling
to ground to operate and due to its size, it also acts a current gathering
device for the those current that would otherwise floe through the lossy
ground.
	Elevated radials usually operate in the resonant mode at the lowest
frequency of interest and it is a known fact that their being nonresonant at
the higher frequencies- although longer than a quarter wavelength- do not
detract from correct antenna operation. But, even then 3 or 4 radials only
produce a very definite, although minor deformation of the radiated field.
N6PL recommends at least 6 radials even high in the air. He should know: he
designed vertical or the Navy for a long time!
	if you go for the counterpoise type, you might even consider adding
a ground wire tuner to optimize matters.
Alex	4Z5KS

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