Maratrac on split site repeater
Moderator: Queue Moderator
Maratrac on split site repeater
I'm using a maratrac lowband and a m1225 uhf link. On the receive radio I have the cor out of the lowband to the controller and tx audio and ptt to link. I can transmit on the receive freq and it keys the link up and passes audio without a problem, but when you unkey the link radio will flash tx on and off. I have turn the squelch up on both radios and it can't be coming in on the receive radio because I have a monitor on it and the link. Any ideas? AG4TI
Re: Maratrac on split site repeater
It's called ping-ponging, and it's a pain in the butt to resolve without a way to delay expressing COR immediately after a dekey. Think of it as a self actuating relay, or a pair of logic gates set to trigger each other.
Rcvr 1 senses carrier and its COR pulls in PTT on Xmit 2.
Rcvr 1 loses carrier and drops COR. Xmit 2 drops PTT.
Rcvr 2 gets a bump from the xmit and momentarily applies COR which keys Xmit 1.
Xmit 1 keys and dekeys which bumps its rcvr causing it's COR to bounce.
Xmit 2 keys and dekeys which bumps its rcvr .....
Way too much fun. Hilarious to listen to, but not very useful. If your squelch circuits won't clamp it effectively, then you'll need to design / add some delay to the COR lines so they can suffer through these rcvr falsing and stop ping-ponging. A few hundred milliseconds from a simple RC time constant on each PTT/COR line should do. You may be able to build it into the Maratrac since it has more real estate inside.
Rcvr 1 senses carrier and its COR pulls in PTT on Xmit 2.
Rcvr 1 loses carrier and drops COR. Xmit 2 drops PTT.
Rcvr 2 gets a bump from the xmit and momentarily applies COR which keys Xmit 1.
Xmit 1 keys and dekeys which bumps its rcvr causing it's COR to bounce.
Xmit 2 keys and dekeys which bumps its rcvr .....
Way too much fun. Hilarious to listen to, but not very useful. If your squelch circuits won't clamp it effectively, then you'll need to design / add some delay to the COR lines so they can suffer through these rcvr falsing and stop ping-ponging. A few hundred milliseconds from a simple RC time constant on each PTT/COR line should do. You may be able to build it into the Maratrac since it has more real estate inside.