Topband: Monopole Elev Pattern w.r.t. Earth Conductivity

[Richard Fry]

Dave WX7G wrote:
>For DX we are interested in elevation angles from 3-15 degrees. How much 
>error is there in a NEC model of a monopole at these elevations?

The link below shows the NEC4.2 fields for a seawater path on 1850 kHz.  The 
calculated field at 1 km in the horizontal plane for 1 kW of applied power 
is 309 mV/m.

The theoretical maximum field for that system at 1 km in the horizontal 
plane, over a perfect ground plane is 313 mV/m.

The fields at low elevation angles above the horizontal plane are nearly the 
same.  As NEC calculates the horizontal plane field accurately, the other 
fields shown there will be equally accurate.

As shown in my earlier plot for seawater, 5 mS/m and 1 mS/m, the shapes of 
the elevation patterns close to a monopole are very similar to each other 
for those different conductivities.

http://i62.photobucket.com/albums/h85/rfry-100/160m_Qtr_Wave_ElPat_at_1km.jpg

R. Fry