I agree. I have found very few receivers I could not locate a good squelch logic output easily. I always used the bi-polar transistors (such as 2N3904 and 2N3906) for the added circuitry needed.
Neil - WA6KLA Joe Montierth wrote: > > --- Dave <[EMAIL PROTECTED]> wrote: > > > > I use a couple of EF Johnson Challenger 71xx UHF > > mobile radios for > > the RX and TX side of one of my repeaters. Obviously > > there is no COR. > > A makeshift COR signal is the busy LED which works > > to a point. The > > busy LED lights up whenever there is ANY AND ALL > > signals on the > > frequency regardless of the PL tone. A static crash, > > the noise floor > > raising, a DX repeater, etc... it will trigger the > > transmit on the > > repeater, but the audio will not pass because that > > is filtered by the > > call guard (PL ). What I need to do is I need to > > grab the signal from > > the squelch gate trigger to make a true COR. > > > > However, directly taping to the trigger point with > > the controller > > loads down the whole thing and nothing is received. > > I've tried using > > a radio shack mps2222a transistor to make a > > transistor switch and > > still, it loads it down. I'm thinking now of using a > > quad buffer/line > > driver or something like that, but thats going to > > use a lot of space. > > I'd prefer to just use a transistor or something. > > Something that I > > can solder flat to the PC board and not have to run > > a pile of wires > > and add a circuit board. > > > > Does anyone have any ideas --- know of any > > transistors that could be > > used that will not load down the gate/squelch? I > > need something that > > is almost transparrent to the gate trigger. > > > > Thanks > > > > Dave > > N9NLU > > > > It's hard to say exactly what you need without knowing > some voltages, etc. What is the voltage at that point, > squelched and unsquelched? When you installed the > transistor, did you use a series resistor to the base > of 100K or greater? This is an easy problem to solve, > you just need to get the right values of parts. > > Joe > > __________________________________ > Do you Yahoo!? > Yahoo! Finance Tax Center - File online. File on time. > http://taxes.yahoo.com/filing.html > > > Yahoo! Groups Links > > > > Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
