RE: [Repeater-Builder] Re: Motorola Duplexer Info Needed

[Bill Hudson]

 

There you go Joe!  The man with all the answers!  That sounds like the exact
situation you have!

 

Good work on that info!  

 

Now I'll have to go back and see what the deal was with the duplexer we had
here!

 

Bill - W6CBS

 

  _  

From: Repeater-Builder@yahoogroups.com
[mailto:repeater-buil...@yahoogroups.com] On Behalf Of nj902
Sent: Wednesday, December 03, 2008 2:02 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Motorola Duplexer Info Needed

 

The technical data for the UHF MSR2000 duplexers is contained in a 
section of the UHF station manual, 68-81061E55, behind the "OPTIONS" 
tab.

This section was not included in the original -O release of the 
manual but is definitely in newer manuals such as the -C version.

The MSR2000 duplexer family consists of several 2 and 4 cavity 
models covering the frequency range from 406-520 MHz. The same 
TRN9041A cavities are used in all of the models, thus the mechanical 
construction of the cavities should not be a factor in your issue.

Different antenna and interconnect cable sets are used for each of 
the three frequency ranges: 406-430 MHz, 430-470 MHz, and 470-520 
MHz.

The 4 cavity T4085A models operate at T-R spacings of greater than 3 
MHz whereas the T5002A models are configured for separations between 
2 and 3 MHz. These use a different set of coupling loops than the 
T4085A.

The maximum input power specification for these duplexers is 250 
Watts.

--

--- In Repeater-Builder@ 
yahoogroups.com, "Joe Burkleo" 
 wrote:

"I have a Motorola 4 can duplexer out of a UHF MSR2000 series radio 
that is the pass/notch style. ...

I can not find any info on this unit ..."

 

Re: [Repeater-Builder] Re: Motorola Duplexer Info Needed

[Bob M.]

There is an older T1500-series manual on the web site that goes along with this 
Yahoo! Group.

There are two rather different coupling loop assemblies/setups in those cans: 
those that arranged for the notch ABOVE the passband, and those that are 
arranged for the notch BELOW the passband. I doubt you can arbitrarily reverse 
them.

The various cable sets are only documented by the colored dots on the 
connectors. I didn't see any actual cable lengths.

I think they use the same unit on the Quantar and there might be a newer 
document in that manual, but I doubt anything has changed in those cans in 30 
years.

Bob M.
==
--- On Wed, 12/3/08, Joe Burkleo <[EMAIL PROTECTED]> wrote:

> From: Joe Burkleo <[EMAIL PROTECTED]>
> Subject: [Repeater-Builder] Re: Motorola Duplexer Info Needed
> To: Repeater-Builder@yahoogroups.com
> Date: Wednesday, December 3, 2008, 4:20 PM
> Bill,
> That is interesting that you are having the problem with
> the duplexer
> not tuning down to 440.8.
> 
> This duplexer that I have will tune down to at least 440.0
> with no
> problem on the duplexer running out of pass tuning range.
> The problem
> that I am having is with the notch sliding adjustment on
> the top of
> the cans running out of adjustment range on the notch
> tuning. The
> screwdriver pass tuning adjustments on the front of the
> unit have
> plenty of range. I never did run them all the way in just
> to see how
> far they would go, but they will go well below 440.8. I
> will try your
> suggestion of tuning it up on the higher end of the band
> tonight if I
> get home early enough.
> 
> I have one of these style duplexers on our 444.525/449.525
> 225 watt
> Micor repeater running at 150 watts with a Angle linear
> preamp on the
> receiver with no problems, so I know they can be made to
> work at the
> higher end of the band.
> 
> I don't think a T1500 deries duplexer will perform as
> well at that
> power level.
> 
> I was hoping someone had a manual that covered the
> duplexer. I can not
> find any reference to the specifications or parts list in
> the MSR or
> MSF manuals that I have.
> 
> Thanks,
> Joe
> 
> --- In Repeater-Builder@yahoogroups.com, "Bill
> Hudson" <[EMAIL PROTECTED]> wrote:
> >
> >  
> > 
> > Joe
> > 
> >  
> > 
> > You just happen to have one of the series of duplexers
> that does not
> make it
> > all the way down into the bottom of the ham band at
> 440.xxx Mhz.
> > 
> > If it truly is the Motorola duplexer out of the
> MSR2000 series
> repeaters,
> > they - in fact - do not tune down to the bottom of the
> band.  The
> original
> > T-1500 series duplexers make it fine, but the
> mechanics of the tuning in
> > these specific cavities "bottom out" before
> making it to the lowest
> part of
> > the 440 - 450 MHz. band.
> > 
> >  
> > 
> > What you are experiencing is normal.  Trying tuning it
> up in the 444.9 /
> > 449.9 range, and you will see it works fine.
> > 
> >  
> > 
> > Maybe you can trade it with one that you know will be
> going on a higher
> > frequency.  
> > 
> >  
> > 
> > Interesting timing on your post.  I just became aware
> of this myself a
> > couple of months ago.
> > 
> >  
> > 
> > Bill - W6CBS
> > 
> >  
> > 
> >   _  
> > 
> > From: Repeater-Builder@yahoogroups.com
> > [mailto:[EMAIL PROTECTED] On Behalf Of
> Joe Burkleo
> > Sent: Tuesday, December 02, 2008 11:24 PM
> > To: Repeater-Builder@yahoogroups.com
> > Subject: [Repeater-Builder] Motorola Duplexer Info
> Needed
> > 
> >  
> > 
> > Hello,
> > I have a Motorola 4 can duplexer out of a UHF MSR2000
> series radio
> > that is the pass/notch style. I am pretty sure
> Motorola also used
> > this same duplexer on the MSF5000 series of radios. I
> can not find any
> > info on this unit and I am having a problem with the
> notch on the low
> > pass side. I can not seem to adjust the notch past 4.5
> MHz spacing. It
> > will adjust down to 3 MHz spacing just fine. The notch
> on the high
> > pass side adjusts just fine and will actually go a
> little beyond the 5
> > MHz spacing.
> > 
> > The pass adjusts properly on both sections of the
> duplexer.
> > 
> > It was originally on 464/469 and I retuned it to
> 440.8/445.8. The
> > notch problem was there on the original frequency as
> well.
> > 
> > I am using a IFR A-7550 analyzer/tracking generator
> for alignment. the
> > duplexer has very good insertion loss and the notches
> are -100 db, so
> > it is meeting specs very well, other than the one
> notch being off.
> > 
> > Has anyone ran across this before or have any ideas. I
> though I would
> > ask the group, before I started drilling out pop
> rivets to disassemble
> > the cans from the mounting bracket.
> > 
> > Thanks,
> > Joe