[Motorola] MSR-2000

[Eric Lemmon]

Steve,

My MSR-2000 UHF Service Manual shows that the standard transmit channel
element is a KXN1095A.  I have no idea why the number is different from what
you have.  I am pretty certain that the KXN1095A is a 2 PPM unit.

Since you have tried two different channel elements and experienced the same
symptom, it may indicate a problem in the exciter.  You might check voltages
against the service manual.  If the channel element is receiving a low
operating voltage, it will likely be very unstable.

It's always better to send the channel element in to be fully compensated
with a new crystal.  Although I haven't used Bomar in more than 30 years,
I've read a few posts that claimed Bomar didn't actually do anything to the
channel element beyond merely testing that the crystal could be centered on
frequency.  Moreover, the term "compensation" is rather vague unless it is
spelled out as to what actions will be taken in that process.

I know for a fact that International Crystal (ICM) not only tests the
incoming channel element first to ensure that it will work with the new
crystal, but they also do more than merely compensate the channel element
for temperature drift.  The newly-crystaled channel element is also tested
for sufficient output, for tuning range each side of center frequency, and
for response to modulating signals.  This last point is very important,
because the freshly-crystaled channel element is of little use if it cannot
be deviated fully with the modulating signal.  Some crystal houses never
test the crystal to see if it can be modulated to meet the radio
manufacturer's specification.

If you don't have a spare channel element of the correct model, you can
purchase one from ICM if they have one in stock.  Also, you can exchange
channel elements with ICM in most instances.  That is, you can send in a
working MICOR channel element with your order for a new MSR-2000 crystal and
ICM will send you a fully-compensated MSR-2000 channel element.  Contact
Cecelia Brown at ICM to work out these details in advance of your order.  Of
course, you must pay the $30 for the compensation service in addition to the
crystal price.  The nice part about this deal is that you can put the order
on a credit card over the phone, and ICM will start working on it
immediately while your trade-in channel element is still in the mail.

Disclaimer:  I have no financial interest in ICM; I am merely a longtime
satisfied customer.

73, Eric Lemmon WB6FLY
 

-----Original Message-----
From: motorola-bounces at mailman.qth.net
[mailto:motorola-bounces at mailman.qth.net] On Behalf Of Steve Tripp
Sent: Monday, March 05, 2007 8:30 AM
To: motorola at mailman.qth.net
Subject: [Motorola] MSR-2000


 I have an MSR-2000 on 440 and running quite nice with one exception. I find
that the TX drifts more than I like. It moves +/-1 kHz and is EXTREMELY
critical to adjust. It moves kHz's with minimal adjustment. I ordered Bomar
xtals and installed them myself. After some aging, I noticed the drifting. I
bought another set of kxn-1088 and 1086 and had Bomar install and temp
compensate. The same drifting occurred. 

Would International do a better job? Does anyone know where I can get the
2ppm elements. 

Thanks for any suggestions. 

Steve
K1IIG