[BC] "live" feeds

[Ron Youvan]

> Mike's comment about the IFB feed is a good one. In fact, you could use the
> same pair for IFB if a second one isn't available. If you use center tapped
> transformers a D.C. voltage can be used to control a "simplex" circuit
> whereby a relay can be used to switch between send and receive. 

   If you use good quality properly center taped transformers you can
easily feed the audio to be aired out balanced and the feedback (cue)
back center tap to ground on each end, the cue channel will need to
pass through a high pass filter (some Op-amps) that kill everything
below 150 Hz or so.  It will also pass a DC Voltage to light a light
or ring a buzzer,  (with a transistor, relay or something) either way.
(assuming as dry pair)
-- 
    Ron  KA4INM
         Youvan's corollary:  Every action results in
                              an unwanted side effect.