Hi, all...

OK - I was hoping that 80W would be enough of a drop.  Wasn't aware until
these responses (yours and others) that the MSR PA was not rated for
Continuous Duty.

I'd have to check the model suffix - I don't remember right off hand.

No - no circulator at this time. Seems SWR was low last we checked it, but I
can't remember the specific reading - I think it was around 1.3:1, though.

We followed the tuning procedure in the manual.  We also used the Motorola
test panel, so it was literally "by the book"...

Last time we measured it (when we put the PA in the last time) RX
sensitivity was about .5 µv straight into the receiver, .62 after adding the
tone panel, and almost 1.0 after adding the duplexers.

>>All things considered, a working MSR is a good unit.
That's what I hear - I just wish I could get ours working, and keep it
there.  :(

Mark - N9WYS


-----Original Message-----
From: skipp025 [mailto:[EMAIL PROTECTED]
Sent: Tuesday, September 07, 2004 10:46 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: MSR2000 PA out - again...

> "N9WYS" <[EMAIL PROTECTED]> wrote:
> I have an MSR2000 on 444.550 for the
> local ham club / county EMA.  The PA (a
> 110W model) is out again.  We just had
> this repaired by the local Motorola
> shop, with whom we've had very good
> results from in the past.  We're running
> the PA at about 80W,

Not good, 60 watts max for typical repeater
operation is about as far as I'd push it.
You probably would not have noticed the
repeater doing 40 to 60 watts vs 80.

> so I'm thinking we didn't "burn it up",
> but I can't help but wonder if there
> is anything inherently wrong with the
> MSR2000 PA for UHF.

There is, do you have an A or B version
(model number suffix at the end)?

> This is the third time the PA has failed
> in this particular machine in about a
> 2-year time frame.

You've got more than a PA problem. Possible
high reflected power or lock to talk users.
Do you have a circulator following the
transmitter?

> (This was a repeater originally tuned
> for 460 MHZ, and brought down to the ham
> band.)

And how was that done..?

> This particular machine has been a pain in
> the @$% - RX sensitivity isn't what it should
> be,

What is it..?  You might have some lightning
damage in the receiver front end.  One of the
Canadian guys mentioned this problem a month or
two back.

> PA keeps going out, etc. Seems like we're up
> at the site every couple of months do
> make some sort of repair on it.
> I'm wondering if we should just cut our
> losses and get another machine, or
> should I keep plugging away at this repeater?
> If we do decide to chuck it, how much can I
> expect to spend to get a comparable replacement
> - we use this machine during severe weather
> season for forwarding reports to the NWS, and
> it's open other times.  We want to add remote
> RX sites (you've probably seen my inquiries
> about those in the past) but I don't want to
> start adding remote RX sites until I get the
> main repeater working reliably.
> I'm open to suggestions...
> Thanks,
> Mark - N9WYS

I can't tell you what is best for your needs, but
the PA issue is probably bigger than just that
one part (the power amplifier). A circulator and
a fan would be a godsend if you must run the 80
power level in the stock PA.
You can repair it again, buy an $1100.00 drop in
replacement from TPL or sub something else in. I've
done all three, now I'm making my own predriver
units for larger trailing PA's.

All things considered, a working MSR is a good unit.

cheers
skipp
skipp025 at yahoo.com
www.radiowrench.com





 
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