[Motorola] Strange MSR-2000 Duplexer

[Eric Lemmon]

Jay,

The number TKN8293A is a current part, but it's a cable for a duplexer, and
it costs $94.

After poking around in my MSR2000 manual, I found that the TKN8293A cables
are used to connect the two outboard filters of the duplexer to the TX and
RX terminals.  The duplexer associated with these cables is a TLD2502A
comprising four rectangular filter cans mounted to a 3U panel.  It is
specified to cover 148-174 MHz.  When properly tuned, is should have an
insertion loss of 1.7 dB, RX and TX notches at least 82 dB, and a minimum
RX-TX isolation of 52 dB.  It is designed for a minimum RX-TX separation of
1.5 MHz, and it can handle 125 watts.  The design is unique to Motorola.

FYI, the TLD2502A duplexer is worthless at 600 kHz splits in the 2m Amateur
band.

73, Eric Lemmon WB6FLY
 

-----Original Message-----
From: motorola-bounces at mailman.qth.net
[mailto:motorola-bounces at mailman.qth.net] On Behalf Of Coote, Jay
Sent: Monday, April 23, 2007 9:34 AM
To: motorola at mailman.qth.net
Subject: [Motorola] Strange MSR-2000 Duplexer

I am looking for tuning instructions for a VHF duplexer found in an
MSR-2000 repeater cabinet.
The only numbers seen are TKN8293A.  I can furnish digital photos to aid
in ID'ing.
It looks like it was made for Motorola.
 
Thanks