Topband: Angle of radiation to local stations?

[D. Rodman, MD]

I did some on air testing with some bidirectional antennas for 160m and
the results were somewhat surprising to me.  It appeared the antenna which
should have favored the direction of the local stations was an S unit
lower.  The antenna is a low angle radiator with vertical polarization.
When I checked the modeling of the antenna, I see the low angles favor one
direction for DX but the higher angle signals are several dB stronger in
the opposite direction.  This leads me to think about what angles 160m
stations within 15 miles might be copying best.  If this is high angle, my
observations are explained.  I am confident the ground wave propagates
based on field strength for a while but I am not sure what distance
skywave at higher angles begins to seriously affect on this band.  I am
most familiar with the upper bands.  Thanks.

David J. Rodman, MD 

Assistant Clinical Professor 
Department of Ophthalmology 

Research Assistant Professor
Department of Chemistry

State University of New York at Buffalo

FAX 716-859-4565 
Office 716-854-1137

e-mail: rodman at acsu.buffalo.edu