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
