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The TS-64 needs a series resistor with the encode line maybe a
47K,
otherwise it will load the audio line.
Juan
----- Mensaje original -----
Enviado: Wednesday, July 28, 2004 8:10
PM
Asunto: [Repeater-Builder] Re: MSR-2000
Deviation Question
Ah ha!! I have finally found the problem. Skipp and Kevin
both
suggested that I look long and hard at the channel element, and just
to be sure, I ordered a new one today from ICM. But that was not the
problem ;o) That's okay, as I really would prefer a new ICM element
anyway.
Went down to the shop tonite to conduct some tests on the
channel
element that Skipp suggested to me, injecting a high level PL tone
into the PL tone input of the exciter. I figured I would first
disconnect the TS-64 tone board, and monitor that point with a scope
to see exactly what was hitting the "splatter filter" in the
exciter's
audio chain. As soon as I plugged the radio in, I knew we
had found the
problem as the deviation increased several fold. For
some reason, the
TS-64 was pulling down the audio line. Disconnect
it and now the
modulation is clean as a whistle (grin) at 1 KHz to
over 6 KHz deviation.
No distortion is evident on the service
monitor scope at all.
In
thinking back over all the symptoms, the fact that I was seeing
increasing
deviation with increasing audio frequency feeding an
audio generator
directly into the exciter should have been the tip
off. All of the
pre-emphasis I believe is done external to the
exciter, yet I was seeing
obvious pre-emphasis, and could not make
rated deviation at 1 KHz audio
frequency.
I've got several brand new TS-64's on the shelf, and will
install a
new one tomorrow.
To put it mildly, I am really stoked
that the problem is finally
solved. Thanks very much to those who tried to
help me with this.
Ah, life is good!
73,
Army -
AE5P
--- In [email protected],
"Army Curtis - AE5P"
<[EMAIL PROTECTED]...>
wrote:
> Good point. The channel element was simply recrystalled by the
folks
> we bought the MSR-2000 from, and I also am looking hard at
it. I
did
> try another channel element I had on hand that was done
by Channel
> Element Headquarters, and it did the same thing. I believe
I will
> send one of them off to ICM and have them do a new one that I
KNOW
> will be right, and see if that makes a difference.
>
> We bought 4 of these repeaters, and I'm about at my wits end with
> them. I believe my next step while I'm waiting on the new channel
> element to come from ICM will be to convert one of the other 3,
and
> see what it does. And I believe I may give the Squelch Gate
card
> interface a try, at least for the audio interface. Can't hurt
;o)
>
> Thanks for the ideas.
>
> Army -
AE5P
>
> --- In [email protected],
Kevin Custer
<[EMAIL PROTECTED]...>
>
wrote:
> > Army Curtis - AE5P wrote:
> >
> >
>No. The output of the controller goes to the Squelch-Gate card,
>
and
> > >through the several stages of audio amplification there
before
> going
> > >on to the exciter. Since that was the
way Motorola designed it,
> it
> > >seemed like the best
way to keep it.
> > >
> >
> > Who did the
channel element? If you re-crystaled it yourself,
it
> likely
> > isn't working correctly. Try another (factory) channel
element
to
> see
> > if the problem goes away. If
it does, consider having ICM or
> Bomar redo
> > your
element.
> >
> >
Kevin
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