[Elecraft] Nasty spurs on RX with new KPA500

[Andy Durbin]

"Connecting the RX directly to the antenna and the spurs are not there,.."

That seems to suggest that the signal is coupling through the T/R switch.   What happens if you key the KPA500 by grounding the key line input but leave the transceiver in RX mode? (Need to be in OPER mode).  Look for the * on the left side of the KPA500 LCD to confirm keying.

Just to be clear - this is not a transmit test, just changing the state of the T/R switch in the KPA500.

Another test - leave the RX on 10 m and cycle through the KPA500 band  selections using the KPA500 band switches.  Is there any change in amplitude of the spurs?

73,
Andy, k3wyc