Doug - I just saw this post and you may already have a solution. If not, then you could use a triac to switch the ac relay and a PNP transistor to switch the triac. The transistor would be turned on by pulling the base to negative through the open collector output of your transceiver. You would need to make a simple dc supply powered from the 13.8 vac supply in the amplifier. All of the new components could probably be mounted in the amplifier. Let me know if you want to pursue this.
Jack, KO?T?
