Topband: Detuning/Grounding Xmit Antenna while on RX

[John K9UWA]

> 
> So, depending on what your radio main antenna port looks like when switched to
> receive antennas, you might be able to add 1/4 wave of coax and have exactly the
> same effect with no additional switching at all.
> 
> Otherwise, you run a risk of creating relay sequencing issues. You have to be
> careful, and you must use a relay system and a control system that does not hot
> switch a relay. 
> 
Years ago at old QTH I did that. Feedline from Amp to Shunt Fed tower was set at 1/2 wave electrical length. 
Then between the Amp and Transmitter I placed a Relay box that Grounded the Transmit Antenna during
Receive. Only needed to deal with relay for 100 watts that way. Relay needs to be fast closing and slow in opening to
as Tom says prevent hot switching.
John k9uwa
John Goller, K9UWA & Jean Goller, N9PXF 
Antique Radio Restorations
k9uwa at arrl.net
Visit our Web Site at:
http://www.JohnJeanAntiqueRadio.com
4836 Ranch Road
Leo, IN 46765
USA
1-260-637-6426


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