Al Christman, K3LC wrote a comprehensive article in the March/April 2004
issue of NCJ entitled:
"Maximum-Gain Radial Ground Systems for Vertical Antennas"
Data was derived from using NEC4 with #16 wire just below the
surface and a 1/4 wave vertical element.
It covers 160, 80 and 40 meters and the optimum number of radials
and lengths for total wire length versus very poor, average and
very good soil conditions with graphs and data points.
For example, from Table VII which is entitled:
Optimum number and length of radials for a vertical antenna on 160 meters
(1.835 MHz) operating over average soil (conductivity = .005 Siemens/meter
and relative permittivity=13).
Total wire Optimum number of radials Optimum length of radials Peak
gain
in ft. in ft. in ft.
in dBi.
500 11-12 45.45-41.67
.11 dBi
1000 17-18 58.82-55.56
.38 dBi
2000 23-28 86.96-71.43
.63 dBi
4000 32-40 125.00-100.00
.89 dBi
8000 45-55 177.78-145.45
1.17 dBi
16,000 76 210.53
1.48 dBi
32,000 99-122 323.23-262.30
1.75 dBi
Previous articles are available at the NCJ website but I couldn't open this
particular
one for reference.
http://www.ncjweb.com/index.php?backissue=2004<http://www.ncjweb.com/index.php?backissue=2004>
The link may have to be typed manually since my e-mail has an HTML tag.
73, Jim, K1PX
K1PX@msn.com<mailto:K1PX@msn.com>
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