Moonlight

I got away from solving the problem interfacing the ID-O-Matic with the RT97S to take care of immediate problems around the house. I determined that the COR out on the RT97S does indeed have audio on that line and will feed back into the COR in and modulate the radio given a chance. I was really disappointed with the engineering frankly. I conjured up this very simple circuit that I bread-boarded that solved the audio feed through problem. It's also a very cost effective solution and easy to build. The components can be obtained online or whatever you might have in the junk box. Only things I ordered was the LM44D00 two pole relay, some 2N2222's and green LEDs that gave be a visual feedback of operation. The LED and associated resistor can be eliminated if desired. The circuit works almost perfectly with one exception. When the ID-O-Matic activates and keys the radio you cannot key the repeater until the ID-O-Matic relinquishes the COR in line. This means during that short brief time during the courtesy beep the repeater cannot be keyed. This shouldn't be a problem in most cases since the beep duration is very short. And on air etiquette usually means a user pauses for a couple of seconds to allow another user to join the conversion. So not a real problem. This is true also when the unit is sending id. My unit ids in CW and voice. Takes just a few moments so it shouldn't be a real problem. But at least the horrible feed-through problem is fixed. I also put 16 pin DIP sockets on the board for the 4049 chip and the miniature relay. Hope you find this useful and if so and you hear of others with the same problem with this configuration feel free to share the circuit diagram to them. Best of luck with your project. WRLY353

I' m having a problem with the COR out on the RT97s to COR in on the ID-O-Matic (latest version). The repeater trips the controller OK but the controller produces a voltage that back feeds into the RT97s COR circuit causing problems. One of the problems is a loud white noise being transmitted. Sounds like an open squelch. Disconnecting them and manually tripping the controller and the problem goes away. Courtesy beep works as it should and the loud white noise vanishes that the repeater was broadcasting. It appears some kind of isolation circuit is required like a reed relay or maybe a MOSFET. Anybody run into this problem? What was your solution? The COR on the RT97s goes low on carrier detect. The controller is expecting it's COR input to go low on trigger. When they are connected as expected the problem appears. Putting a meter on the line I see the voltage at about 2 volt on the COR line Then on key up there is a very brief drop like a pulse in voltage before coming back up to the 2 volts. It should stay low as long as its being keyed. Any ideas on a MOSFET isolation circuit? Any ideas would be much appreciated. Thanks in advance, WRYL353