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Re: Transmitting while listening in diversity mode

Posted by Scott Ellington on Jan 07, 2011; 4:14pm
URL: http://elecraft.85.s1.nabble.com/Transmitting-while-listening-in-diversity-mode-tp5897822p5899779.html

If the power coupled to the RX antenna is too high, or you just want to be safe, add a small relay in the RX antenna feedline to disconnect it and ground the RX input on transmit.  Radio Shack 275-241 works well.  I run the 12V coil on 70 V, with a series resistor, to make it switch faster, but it would probably be fast enough for QSK on 12 V.  A reed relay would probably be barely audible.

If the sound of the relay bothers you, the same can be done with PIN diodes, though it's a bit more complicated. One could probably just copy the circuit of one of the switches in the K3.


73,

Scott  K9MA




Scott Ellington
Madison, Wisconsin
USA



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