Everyone Thanks for your responses.
Do you check the Amp Key Interrupt box in the KAT500 utility software or does this occur automatically when using the Elecraft recommended set up with an Icom 7300, KPA500 & KAT500?
My set up is:
Icom 7300 Tuner Control Plug to power and Tune KAT500.
ACC line from Icom 7300 to KAT500 PTT relay, RCA connection from KAT500 to KPA500 PA Key Plug.
Thanks, Irwin KD3TB--