Chris It is some sort of earth loop - I can't be more specific since it depends on your installation. I have heard the same when I put my headphone switcher in the same box as the controller I use for copying freq/mode between the two K2s here. I found mine by systematically disconnecting the variious control and audio cables and earth lines. 161 Bob G3PJT _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft
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