Fred, Are you looking for a circuit that will reset the controller if PTT is active for more than a continuous 10 minutes??
If so I have one I designed about 10 years ago. It is used to reset the controller from a continuous 10 or so minute PTT. It removes the power from the controller for about 1.5 second and then reconnects. I had a few PC boards made of this. If you like I can send diagram of circuit. Requires a dual op-amp, LM358 with some Rs & Cs and a pass transistor. It can handle over 0.5 amps. The unkeying, going high, ptt reset the circuit. If you are looking for something to keep power removed then this circuit is not for you. Let me know. 73, ron, n9ee/r >From: w6jll <[EMAIL PROTECTED]> >Date: 2008/04/21 Mon PM 06:02:33 CDT >To: [email protected] >Subject: [Repeater-Builder] Carrier Control Timer > >With regard to Tom's use of a carrier control timer - I am using GE >EXEC II and MVP's in my system. Although I have relied on the external >controller's time out functions, I would like to have a "backup" timer >in the transmitters that would take the repeater transmitter off the >air at say 10 minutes, if for some reason the contoller circuit failed. >I've looked at the 555 but the problem is that in the monostable mode, >the pulse input to start >the cycle has to be shorter than the timing cycle (according to some >design notes, about 1/3rd or less). Obviously, this won't work for the >intended application since the pulse (key down) would be longer than >the timing cycle. I'm sure someone on the bulletin board has >designed/implemented what I'm looking for. Any thoughts would be >appreciated. TNX Fred W6JLL > > > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
