A 555 would be a solution. Off the shelf 3 minute delay timers for air conditioners are common. 3 minutes might be a bit long. Don't know if have shorter ones.
They simply delay an air conditioner coming on for 3 minutes if power is lost primarily to permit the unit to come on when hopefully other conditioners have already fired up. If a large number of air conditioners come on at one time it starves the power system dropping line voltage causing undue wear. Now if all conditioners have the same 3 minute timer then still a problem. Guess the timers are not that accurate so might not be a problem. Just wire the contacts to the low tx power. This would be more expensive than a 555, but could be mostly plug-and-play solution. I am sure there are other such delay timers. 73, ron, n9ee/r >From: Mel Farrer <[EMAIL PROTECTED]> >Date: 2008/04/20 Sun PM 04:56:57 CDT >To: Repeater-Builder@yahoogroups.com >Subject: Re: [Repeater-Builder] Need time delay circut > >A couple of ways. 1. Using a NE555 as a timer, circuits are everywhere. 2. >I use a 2N7000 fet and pull in a low current relay on the PTT line. Use a >regulated low voltage to a RC timeconstant you want to the gate. When the >voltage gets at the turn on point (around 2.2V) it will pull in the relay. > >Mel > >----- Original Message ---- >From: Thomas Oliver <[EMAIL PROTECTED]> >To: repeater-Builder@yahoogroups.com >Sent: Saturday, April 19, 2008 9:19:26 PM >Subject: [Repeater-Builder] Need time delay circut > > > > I want to install a timer to inhibit ptt until my tubes warm up on my > transmitter, anyone got any favorites? I am using a .375K Micor PURC and when > power is interrupted and comes back on the exciter drives cold tubes. > Motorola didn't think that was too much of a problem I guess. thanks tom > > > Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try > it now. > Ron Wright, N9EE 727-376-6575 MICRO COMPUTER CONCEPTS Owner 146.64 repeater Tampa Bay, FL No tone, all are welcome.
