[WARC] Manufacturers of Duplexers on 146.640 Repeater Site?

[Leslie Hittner]

The '64 duplexer is a four cavity SinclairVHF duplexer. It was
purchased new from the factory pre-tuned to 146.16/76, which was
the frequency that I thought we were going to be allocated. I
re-tuned it to 146.04/64 upon receiving that allocation from the
Minnesota Repeater Council. It was purchased and placed into
service in 1974-75. Interconnecting tuning cables are a high
quality teflon variety that need not be replaced. The lengths of
these teflon sections are very critical and should not be
tampered with (A call to Sinclair - I think they are still in
business - might be in order to determine if these lengths need
to be changed when a minor change in frequency is accomodated. I
did not change them when I re-tuned it.) The black 1/2-inch
cables that connect the cavities of the duplexer and the
duplexer itself to the outside world could be replaced with new
double shielded cables. Those lengths should be the same (taking
into account differences in velocity factor) as the originals.
In any event, some attention to the crimp connectors on the 1/2
inch black cables may be in order.

I retuned the duplexer without the benefit of a spectrum
analyzer - no small task. As Jim says, however, it is less
difficult with the right equipment. Duplexers - especially if
they are not bumped around - don't "go out of tune." The tuning
on this one, however, might be improved if it is done
correctly - and with the right equipment. Before attempting it
however, I would suggest that you measure the specs. It's not
wise to tune it just because we are in the mood to improve the
site.

I don't know who made the UHF duplexer.

-Les, K0BAD


----- Original Message ----- 
From: "Walt Kelly" <wkelly at hbci.com>
To: <Litvan at acegroup.cc>; "'Winona Amateur Radio Club general
discussion'" <warc at lists.w0ne.org>
Sent: Monday, March 17, 2008 23:02
Subject: RE: [WARC] Manufacturers of Duplexers on 146.640
Repeater Site?


> I believe they are WACO.
>
> -----Original Message-----
> From: warc-bounces at lists.w0ne.org
[mailto:warc-bounces at lists.w0ne.org] On
> Behalf Of Len Litvan
> Sent: Monday, March 17, 2008 8:59 PM
> To: W0NE Listserv
> Subject: [WARC] Manufacturers of Duplexers on 146.640 Repeater
Site?
>
> Can anyone tell me who the manufacturers are for the two
duplexers at
> the 146.640 site--the 2 meter duplexer and the 440 duplexer?
Thanks.
>
> If anyone has recommendations about a source for professional
servicing
> and tuning of duplexers, please pass this information on to me
also.  I
> am requesting this information as part of the club project to
cost out a
> good renovation of the equipment at this site.
>
> Thanks & 73,
> Len KC0RSX
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