[WARC] Manufacturers of Duplexers on 146.640 Repeater Site?

[Len Litvan]

Les,

Thanks for the detailed info below.  Some materials I found confirmed 
the critical length of branch cables interconnecting the cavities.  The 
materials went on to state that cable length might need to be changed if 
the desired frequencies were 4-5% higher or lower than the duplexer 
design frequency and a comparison of operation between design and 
desired frequency operation showed deteriorated performance.

The change in frequency below is less than 1/10 th of one per cent.  
Performance is excellent.  I think we leave the branch cables and 
junction cables alone except to check the crimp connectors as you 
pointed out.

On another subject, are all three duplexers (146.640, 444, and 146.835) 
the band reject (pass/notch) type or are any of them band pass only type?

73,
Len

Leslie Hittner wrote:
> 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....