At 10/19/2008 06:51, you wrote: >Attached is a circuit I have used several times to combine two receivers >into one output. I have used it for adding a control receiver to a >repeater controller as well as two remote base radios into a single port >on a repeater controller, but it can be used to add a second input to a >controller for two repeaters in parallel. > >As Bob indicated, just put the transmitter PTT and audio in parallel, and >use this circuit to combine the two receivers and COS signals into single >audio and COS signals for the input of your controller. > >If you are not using GE equipment, just make sure the COS signals are >around 8 to 9 volts from each receiver when interfaced to this >circuit. If you only have 5 volt COS signals reduce the supply voltage to >the circuit to 5 VDC to use the lower voltage inputs. > >73 - Jim W5ZIT
Actually, I see this thread has come up before. There is a 2 RX selector schematic already in the files section: <http://f1.grp.yahoofs.com/v1/gFn7SNgwCe4RPSRof5FBmjjh2ZJxixJ8p13-b_J0M3Mhalzd88-HZ4QDQeR3zGonWvawWBupWv9CJaIioqtvcvA/2%20RX%20selector%20schematic.png> Although using CMOS gates as audio amps might work, I'm skeptical of their performance. Since they weren't designed for linear operation, they may be prone to significant distortion. Bob NO6B
