[Elecraft] KPA500 hum; horrendous

ANDY DURBIN a.durbin at msn.com
Wed Nov 7 09:41:32 EST 2018


Hum level depends on PA current draw from the torroidal transformer.  What is your PA voltage key down?  What is the complex impedance of the antenna system as measured at the amplifier?


I reduced my KPA500 hum level from intolerable to acceptable by adjusting the transformer voltage tap and bringing the antenna system load close to 50 ohm resistive.


Andy, k3wyc


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