"Hal Rosser" wrote

I also wonder about 'good grounds' for dipoles.
If your terrain was very sandy - so much so that it would take over a
hundred ft of
ground rod to make a difference - then would this mean that your antenna
would
perform as though it was 100 ft higher - than over "normal" ground. ???

I've seen industrial plants use "ungrounded 480volt delta" system, and
with this system, if
any of the 480 v legs come into contact with "ground" (say a wet piece of
concrete floor)
there would be no sparks - as that corner would become the grounded leg.

You might be mixing dc-theory with rf, and looking for a particular
relationship that's not there. The antenna is not 100' higher electrically
as you suggest. In terms of your 100' ground rod, just because it might take
that deep a hole to achieve say, 5 ohms dc-resistance, that does not make
the surface or an antenna above it at an elevated potential with respect to
each other.

A dipole certainly behaves differently over varying resistances of soils.
But the efficiency differences have never been equivalent to the antenna
being at a different elevation because of soil conditions. Now maybe I get
away with less ground loss from a half-wave dipole that is not quite a
half-wave above ground, because my soil is very sandy, is that what you
meant? It doesn't change the electrical height of my antenna any, but the
soil is such a lousy conductor that less is absorbed by a slightly too-low
antenna.

Jack