I have the boom on my TH11DX loaded on 40 meters using a gamma match. I
isolated the truss wires and fed one side through a capacitor.
Problem is that the closest that I was able to get to resonance was 7.7 MHz.
I get reasonable results with a tuner to get it to match on 40m. The match
box that I built actually contains an omega match, but I found that the
extra cap wasn't much help.
It appears that the system wants to have the truss connection moved out a
few inches in order to be able to bring the match down to 1:1 on 7.2 MHz.
But that would mean taking the antenna down.
I was wondering if the gamma match wants the connection farther out on the
boom, or would it also work to add some length to the truss wire in the form
of adding a bit of a loop (droop?) of wire between the gamma capacitor and
the truss wire to make it appear that the line is longer?
Can any one suggest an alternate solution to make the gamma match work at
7.2 MHz? (Cheat the cable into thinking it's fatter?)
Mike
W0IH
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