"Cecil Moore" wrote in message
y.net...
Reg Edwards wrote:
Perhaps some kind person who has been able to afford the latest issue
of NEC4 could calculate the radiating efficiency of a typical vertical
antenna of height 9 metres (29.5 feet) and diameter 50mm (2 inches) -
- when fed against a ground system of 50 uniformly distributed radial
wires, each 1.64mm in diameter (14 AWG) buried to a depth of 25mm (1
inch), of length 10 metres -

Would it help to model this in EZNEC with the radials 1/1000
of a wavelength above ground?

Just heard a funny line on Stargate SG-1 on TV:
"This planet is as dead as a Texas salad bar."
--
73, Cecil http://www.qsl.net/w5dxp

Ground planes above ground can approximate the results
from buried radials. The wires should be several wire diameters
above the ground, and not 10^(-6) wavelengths -- providing
that a finite ground, Sommerfeld/Norton method, is used.
The reflection coefficient approximation will produce large errors.

73,

Frank