Reg:

Here is the results of my analysis of a 99 radial monople:
Height 9 m, radial length from 0.5 to 10m, all conductors
#14 AWG copper, ground Er = 16, resistivity 150 ohm - m.
Radials 25 mm below ground. Antenna efficiency includes
the surface wave.

Radial Radial Radiation Ant
Length Z Resistance Efficiency
(m) (ohms) (ohms) (%)

0.5 63.0 - j 33.6 13.2 17.6
1.0 47.7 - j 18.2 13.2 21.7
1.5 41.8 - j 13.7 13.2 24.1
2.0 38.3 - j 12.5 13.2 25.7
2.5 35.7 - j 11.2 13.2 27.1
3.0 33.4 - j 10.8 13.2 28.3
3.5 31.6 - j 10.5 13.1 29.4
4.0 29.8 - j 10.1 13.1 30.6
4.5 28.2 - j 9.5 13.1 31.7
5.0 26.8 - j 8.9 13.1 32.8
5.5 25.7 - j 8.2 13.1 33.8
6.0 24.7 - j 8.0 13.2 34.7
6.5 23.9 - j 6.9 13.2 35.6
7.0 23.2 - j 6.2 13.3 36.4
7.5 22.6 - j 5.5 13.4 37.7
8.0 22.1 - j 4.8 13.5 38.0
8.5 21.6 - j 4.2 13.7 38.8
9.0 21.2 - j 3.5 13.8 39.5
9.5 20.9 - j 2.9 14.0 40.2
10.0 20.7 - j 2.2 14.2 40.9

Note that the radiation resistance is computed
from the total radiated power (including surface
wave) divided by the RMS base current squared.

The radial input impedance is derived from
the difference between the antenna input
impedance and the radiation resistance. A
fraction of an ohm can be attributed to the
copper losses in the monopole. Also
some of the imaginary part of the radial impedance
must be due, in part, to the input impedance
of the vertical section.

With 0.5 m radials the surface wave accounts for
2% of the total radiated power. With 10 m radials
the surface wave accounts for 5% of the TRP.


Frank
CM Reg's 99 radial Vertical

CM (WG)

CE

GW 2 1 0 0 0 0 0.0968 -0.025 0.00082

GW 35 4 0 0.0968 -0.025 0.026 0.5 -0.025 0.00082

GW 70 4 0 0.0968 -0.025 0 0.5 -0.025 0.00082

GW 105 4 0 0.0968 -0.025 -0.026 0.5 -0.025 0.00082

GR 1 33

GE -1 2

GN 2 0 0 0 16 0.0067

FR 0 1 0 0 8.07 0.01

LD 5 0 0 0 5.8001E7

WG

EN



CM Reg's 99 radial

CM (GF)

CE

GF

GW 1 90 0 0 9 0 0 0 0.00082

GE -1

EX 0 1 90 00 83.83328192 0

LD 5 0 0 0 5.8001E7

RP 1 101 1 0000 200 0 -2 1 200

RP 0 91 1 1000 0 0 1 1

RP 0 19 73 1002 -90 0 5.00000 5.00000

NE 1 1 46 1 200 45 90 1.0 1.0 1

NH 1 1 1 1 200 89 90 1.0 1.0 1

EN