Per Molund wrote:
>
> I am trying to retune an Sinclair Q2330E duplex filter to 145 MHz
> (145.1375/145.7375) from it's factory configuration of 150 MHz
> (150.83/149.80), however the notch atenuation is strongly reduced.
> There is also impossible to set ut the proper bandpass/notch
> separation.
What you are describing has all the symptoms of too much coupling in the
loops. Try reducing the coupling of the loop in one can and see if it
makes it easier to tune the notch closer to the pass and if the notch is
deeper. If so, keep reducing the coupling until the notch depth is
optimized. Repeat on all the cans.
> I noticed fron the Q2330E specification sheet that the duplexer can
> be ordered for 132-150MHz og 148-174MHz, anyone know how I can
> determine which version I have on hand? I would assume the high
> frequency version can give this problem if I try to adjust it to 145
> MHz?
There should be no problem tuning the 148 version to 145 MHz. The main
difference between the two versions would be a longer resonator (and
possibly a longer outside can to accommodate it) and slightly longer
cables. The cables are not highly critical as to frequency from my
experience.
> Can I assume the difference between the two versions are the cavity
> loops and the cable harness?
>
> best regards,
>
> ---per
> LA9XKA
>
Good luck in your project.
Burt VE2BMQ>>>
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