Rick (W-A-one-R-K-T) wrote
I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and
a hold over from the olden days. Check the antenna handbook,
the new philosophy is more and shorter...."
____________

Below is a link to a calculator on the FCC website giving some
insight into this. It restricts inputs to values allowed for AM broadcast
stations, but still might be of some value to amateurs.

For one example, it shows a 1/4-wave monopole using 120 x
1/4-wave buried radials as generating a groundwave field of
about 306 mV/m at 1 km for 1 kW of applied power.

If the number of radials is reduced to 90, and their length is reduced
to 0.153 wavelength, the groundwave field is reduced to 267 mV/m.

The difference in radiated power then is (267/306)^2, or about
24%, which value is dissipated by heating the earth.

Whether or not that reduction is important to amateurs is a judgment call.
But an antenna system producing 267 mV/m for these conditions would be
unusable by a "regional" AM broadcast station -- which per their station
license must produce a groundwave rms field of at least 282 mV/m at 1 km
for 1 kW of applied power.

http://www.fcc.gov/mb/audio/bickel/figure8.html

RF