Miller Family
Art Astronomy Ham Radio Sewing Misc

T1 Tuner Project

80m Antenna


My current antenna is an 88ft doublet up about 40ft and fed with 450ohm window line. It is matched to 50ohms by the Elecraft T1 tuner located at ground level directly below the center of the antenna. The T1 matches the feedline/dipole successfully to ~1:1 SWR on 80m through 6m although the azimuth pattern gets pretty daisy-like above 20m.

I've never paid much attention to the 80m pattern in the past. However I'm often finding that others seem to be able to hear and be heard on 80m much better than me during foxhunts.

I decided to model a configuration that I had heard about somewhere on the web which uses the feedline as a vertical and the dipole wires as a top hat. For the model I used 8 radials 60ft long since that is what is practical at my location.

The graph below shows elevation plot of the comparative gains. The azimuth plots for both are nearly perfectly circular. Pretty dramatic. The doublet on 80m is a major cloud warmer. At 25 degrees the vertical version completely smokes it.

I'm looking forward to trying this out ASAP!

dipole vertical comparison