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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
