One final comment (I hope).
Don't expect cutting the PHYSICAL connection to earth will suddenly stop
earth loss near the antenna, or will make FS suddenly much better.
With four elevated radials there is very little "shielding" or field
cancellation anywhere near the antenna except right under the base of the
antenna. The four radials radiate up, down, and to the sides and couple very
tightly to the earth. The earth between the radials still has large currents
induced in it by the antenna and radials. Only in the far field are all
induction and radiation fields cancelled.
I measured a slight INCREASE (a fraction of a dB) in field strength when I
grounded the center of my test antenna to a eight foot ground rod when using
elevated radials or ground mounted radials when the ground system was small
(but the difference was so small it was unreliable). With a large ground
system there was no detectable difference. I only measured 1.2 dB
improvement going from four ground mounted radials to four elevated radials
(elevated eight feet on 3.7 MHz). I wouldn't call that change staggering, but
it is worthwhile.
I wouldn't suddenly expect to see 10 dB less loss by cutting the earth lead,
since I didn't see that amount with a eight foot height change or by adding a
ground rod connection (while using a large isolating choke on the feedline).
73 Tom
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