[Motorola] MOCOM on Data

[Leo Whiteway]

Ken Cechura wrote:
> 
> so, i essentially need to buiild an amplifier?  Think an LM386 amp inline
> might work?
> 
> At 09:04 PM 2/19/2002 -0800, you wrote:
> >Ken Cechura wrote:
> > >
> > > Score one for me, i got the Rx to work.  Score one for the MOCOM 70 (VHF),
> > > It won't Transmit.  I had a Kantronics KAM rigged in, and it would key the
> > > MOCOM, but i got no audio.  My KPC9612 won't even key up the radio.  Where
> > > is the best PTT point, and where is the best place to feed in audio (also,
> > > do i need to, in some form, transform the audio?)
> > >
> > > I have the former mobile 4 ch MOCOM 70 mounted in the Consolette base
> > > station, so i have multitudes of wires in it.  any help is much
> > appreciated.
> > >
> > > Thanks
> > > Ken
> >
> >Hello Ken; Some time back I connected some TNCs to the MOCOM 70. I found
> >the mike input jack was expected to be connected to a microphone with an
> >amplifier in it. This means that the mike hi pin has a few volts on it.
> >If my memory is ok, The transistor that this voltage came from needed
> >this voltage terminated with the mike amp. I think the impedance of this
> >mike amp was in the neighborhood of a just a few hundred ohms. This also
> >meant the the input must have had quite a high level of audio voltage
> >from the mike amp. I remember adding a 2n2222 into the mike line and
> >played with resister values till I got enough audio voltage to the mike
> >jack to make the deviation at 3.6 khz. I think that was about optimum
> >for what I think packet works best at.
> >73 VE7UW in Kelowna, BC, Canada
> >--
Yup; that is about what I did. If that opamp you are talking about is a
simple op amp then you could adjust its gain with a small pot and get
just what you want. Probably easier than working with a single
transistor.
73 de VE7UW
-- 
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