[BC] Directional FM Antennas

[Thomas G. Osenkowsky]

FM DA's are modeled on a test range using a tower
section identical to the tower being used. Any lines,
conduits, etc. are included in the model. Parasitic
elements are used to directionalize the H & V
azimuth patterns. The exact location of these fixed
elements are carefully documented so the entire
antenna can be installed exactly as modeled on the
test range. There are no variable coils and/or
capacitors as there are in an AM DA phasor.

Tom Osenkowsky, CPBE

> If the directivity is accomplished using parasitic elements 
> as many amateur antennas do, are the directional 
> characteristics monitored in some way?