Monday, May 07, 2007 at 15:39
Mike, the main purpose of using one counterpoise is as an artificial earth. The advantage of using them over a "real" earth is when experiencing RF
feedback type problems.
I found that when I switched from coax to open wire feedline for the wire antenna, that the only way to kill stray RF was to use counterpoises.
I got a decent zap off the CW key! I use 2 wires of slightly different lengths per band. Also, I still use an earth "mat" system under the floor consisting of heaps or copper radials originating from the main earth rod and chicken wire clamped together.
The idea of the mat is to try and have an effective earth to work against when strapping the feeders together thus making the antenna a top loaded vertical.
The main earth rod is under the floor, directly under the antenna tuner.
Mike you may be interested in the present HF wire antenna. It uses
home made open wire feeder - estimated to be 600 ohms into a full wave horizontal (sort of) delta loop that is resonant on 40 metres. Works a treat on 30 & 40 with a significant reduction in noise pick up. It does tune on all bands. Performance on 80 has not been fully tested but RX reports would have it down as compared with the 80 metre flat top zepp.
Cheers, Tony
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