Topband: grounded tower detuning

[Ryszard Tymkiewicz]

 You say you already have a Gamma rod which
 makes me think you also have a simple series matching
 capacitor to your feedline. I would think that relay contacts
 in that drop line  could select either your matching
 capacitor during transmit or another added detuning
 capacitor to radial ground during receive. Hopefully
 resonating a small section of the tower.


Gary I did exactly as Lee K7TJR described...this system
is also showed in John ON4UN book in a chapter 7-94 FIG 7-135.
In my main QTH I'm using 22m high tower with Yagis on a top
and receiving K9AY is about 30m from TX antenna.
I can switch detunning "C" on and off and on 160m the
difference F/B on K9AY is between 1-2 S ! On 80m I can't
see any difference.
I used AUTEK do determine "C" value...it was easy.

                     73 GL
                     Rys
                    SP5EWY






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