The military has developed a system whereby this is possible. It is complex,
heavy, expensive, and doesn't work all that well.

It is possible to mickey one up using relays and diode RF detectors, but it is
unreliable and at some time the failure mode will fire one transmitter directly
into the other receiver. It is a race to see which one burns out first.

Jim




"Nicholas J. Hirsch"
shared these priceless pearls of wisdom:

-A friend of mine is trying to use one antenna with 2 radios in his RV-4
-
- and wants to be able to and listen on both radios and transmit form
-
-ether.... Is there a solution for this such as a combiner or RF
-
-switch that can be used with 2 aircraft radios?
-
-Thanks
-
-Nick
-

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com