[TowerTalk] 80 meter antenna choice

[Tony Brock-Fisher]

I'd like to suggest a pair of phased delta loops. I have such an antenna 
and it works very well.

The apices are supported by a 20' PVC crossarm at 66' on the tower. The 
equilateral triangle loops are tilted away from the tower so the base 
leg  is 40-50 feet apart, and run parallel to the ground, about 6-8 feet 
above it. They are fed 1/4 wavelength from the top which gives vertical 
polarization. The natural loop impedance is around 100 ohms, which can 
be matched to 50 ohms with a 75 ohm section. The two antennas are fed 
with a relay arrangement which provides 180 degree switching, so only 2 
directions are possible. Gain is similar to  four-square.

The antenna provides vertical polarization for good low angle DX 
performance. The base leg acts as a counterpoise, so no radials are 
needed, and low ground conductivity  does not adversely affect 
performance. The frequency can be simply changed from CW to phone from 
ground level by adding stubs at the center of the base leg.

Feed system details available on request.

-Tony, K1KP