Topband: Skywaves from Monopole Surface Waves

[Richard Fry]

>We need sitting-man-with-meter-in-helicopter to go up there and prove that 
>what you get from the ground up to twenty thousand feet out (at) 20 miles 
>is a blend, and not a notch.

Below is a link to the fields calculated by NEC-4.2 for those conditions, 
and also for a horizontal distance of 0.1 mile from the monopole.

The plot for a horizontal distance of 20 miles shows the decay in the fields 
near the earth as a result of earth conductivity along that path, which 
attenuates the radiated field near the surface of the earth.  But those 
fields are not at or near zero, as some expect when looking at the far-field 
elevation pattern of a monopole.

The 0.1-mile plot shows maximum field in the horizontal plane, and rapidly 
reducing fields as the elevation angle increases.  This is to be expected 
for the shape of the radiated field at that distance, which varies 
approximately as the cosine of the elevation angle.

http://i62.photobucket.com/albums/h85/rfry-100/Surface_Wave_Flds.jpg

R. Fry