I always use an NPN transistor (2N4401 or whatever floats your boat) as an
inverter on the Micor COR, with a voltage divider on the base. Micor COR
to base through 10K, 4.7K from base to emitter, ground emitter, collector
becomes active-high COR. Pull up collector with 12V through 1K (or
whatever) if your controller doesn't have a pull-up internally.
--- Jeff WN3A
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Josh
> Sent: Monday, June 21, 2010 11:58 AM
> To: [email protected]
> Subject: [Repeater-Builder] Micor COS issues.... continuing
>
>
>
> I've been fighting this issue for a while now. I've tried
> some bandaids to deal with it, tried multiple repeater
> controllers (including one I designed myself with an
> ATMEGA328 Microcontroller (I'll probably be releasing this
> design as open source coming up)... and I'm fighting the same
> problem everywhere... My micor COS signal is weird.
>
> When the squelch is closed, I get right around 8 volts, taken
> from pin 8 of the modified mobile audio/squelch board - the
> tried and true process just about everybody uses..... When
> the squelch opens, I'm at not ground potential, but right
> about half a volt. This isnt really the sort of logic signal
> I want (I want this thing to be dead nuts zero, not half a volt).
>
> What is the deal here?
>
> I've tried adding resistors in series to fudge things and
> cause voltage drop, but thats not really even working that
> well. I've tried the 2n2222 circuit, but that doesnt really
> have a lot to do with this (although a variation of that
> might come into play I suspect)
>
> How do I best solve this so I can get my repeater on the
> air?? This is very close to the last issue I have remaining to solve.
>
> Help / advice is greatly appreciated.
>
> Josh
>
>
>
>
>
