Hallo Ralf, I've had a similar problem with my K2. It was simply a poor (intermittent) connection in the feedline ;-) ω²LC=1 -- View this message in context: http://elecraft.365791.n2.nabble.com/KX3-antenna-tuner-intermittend-operation-tp7573335p7573469.html Sent from the Elecraft mailing list archive at Nabble.com.