Topband: Rx Loop and Tower Radiating Noise?

[Greg Chartrand]

A good question was asked, what do you do with a shunt
fed tower?

I can think of several different ways to achieve the
same result but they all depend on how the tower is
matched and how close to a resonant antenna the tower
is without any matching components. I have heard some
guys adding components to de-tune the antenna on rx. 

I would suggest the old fashon cut and try method.
Take a portable radio, it should scream anywhere near
the vertical. In the case of a gamma/omega, try
disconnecting the drop wire from the capacitor(s) and
see what happens. If that doesn't work, try adding a
coil to de-tune it. Probably the worst case would be a
grounded tower that was right on frequency. 

I used a 12v relay with 10 amp contacts. I never had a
flashover problem with the relay, its at a low
impedence point so the voltage is not excessive even
at full legal.

Just for fun one day I connected the relay to ground
the wire and used my keyer to open and close the relay
continuously. I walked the neighborhood and could hear
the noise level go up and down with the relay closure
a block in any direction!


Greg
W7MY



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