"Frank's" wrote
Reg, with the antenna we have established as our test model:
All wires #14, monopole 9 m, 36 X 10m radials 25 mm below
ground. Ground parameters Er = 16, resistivity 150 ohm-m.
I have calculated the radiation efficiency including the surface
wave. What is interesting is that the surface wave contributes
very little at elevation angles over 10 degrees.

For 100 W input the total radiated power, not considering
the surface wave, is 31 W. When the surface wave is
included the total radiated power is 36 W.

==========================================
Frank,

So the missing 64 watts, if not dissipated in the radials must be
dissipated in the soil under the antenna.

To prove something, what is the efficiency when the ground is sea
water. Resistivity = 0.22 ohm-metres and permittivity = 80.

PLEASE CONFIRM THE NUMBER OF RADIALS.

I thought you were unable to model 36 radials. Were you using only 1
radial? With only 1 radial my program makes efficiency = 28 percent.
Which would be satisfactory agreement with your 36 % )

Or did you substitute the radial system with a lumped resistance of 5
ohms which I suggested could be used when estimating efficiency?
----
Reg.