I found one unit made by RF Systems - I think it would do exactly what
you want. A bit pricey, in my opinion, at about $100. Google
"automatic speaker switch" to find more.

See: http://www.rfsystems.com/si-2.htm
and http://www.homecontrols.com/cgi-bin/...1969/sesent/00

Eric

"Steve" wrote in message ...
I have a pair of speakers in the cockpit coaming for the AM/FM radio..

I would like to figure out a way to connect the VHF external speaker to one
of these, so I can hear any calls on it in scan or monitoring of ch16.

Both radios are below deck so I can only hear them in the cockpit on a
remote speaker..

I know I could just use a toggle switch, but would prefer to find a way to
combine both outputs so the VHF would be heard over the AM/FM output.

Is there a simple way to do this and prevent one unit from harming the
other??

Steve
s/v Good Intentions