[Elecraft] KPA500 Issue

[Joe Hutchens AJ8MH-Radio]

Looks like the Kenwood switches high during transmit and the KPA500 
requires a low for transmit. KPA500 specs in my manual say +5V max, open 
circuit on receive, closed to ground on transmit.  My old KPA500 manual 
doesn't show Kenwood interconnections.  Only the K3, Yaesu and Icom.

Yup, ya need to supply a low to the amp.

Joe ( AJ8MH )
http://webpages.charter.net/aj8mh-radio/