Good day everyone and seasons greetings,
I have just change from a full size inv vee to a shunt fed tower 24.6m ht, with
4 top loading wires, the antenna dips with a gdo at 1.5 mhz, 110 degs, I have
installed a shunt at 16m point with about 1m spacing I found I could only tune
with a T match I put together, a series cap or an omega match did not give
results, the antenna works great with the T match, I have installed more
radials and am up to 60 now with about 25 of them 1/4 wave, the radials are
still work in progress.
Today I tried the series cap again and moved the bottom of the shunt wire
closer to the mast about 300mm off the mast and found I could tune with a
series C and found a 1.6 - 1 match with about 275 pf.
I have looked at the graph in the ON4UN book and it looks like I am a bit low
with my gamma arm it seems it may have to go to the 19m point and then fine
tune with gamma spacing.
I did want the antenna to be on 1.5mhz so was please at that but could anyone
tell me if I am correct in thinking the gamma arm needs to go up, it would be
good just to use a motorised C possible a vacumm one eventually.
regards HNY all
John G4EIM
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160 meters is a serious band, it should be treated with respect. - TF4M
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