I'm not familiar with those particular duplexers, but the Celwave duplexers
Eric mentioned are easily damaged by over-power. Usually the insulators at
the open end of the resonators (the ends with the tuning slugs) arc over
and/or develop carbon-ish deposits. In cases of mis-tuning, sometimes there
is damage at the cabled ends as well. Their maximum ratings shouldn't be
stressed, and make sure you have a good antenna load, they aren't very
forgiving.
--- Jeff
> -----Original Message-----
> From: Repeater-Builder@yahoogroups.com
> [mailto:repeater-buil...@yahoogroups.com] On Behalf Of kerinvale
> Sent: Friday, August 28, 2009 4:59 PM
> To: Repeater-Builder@yahoogroups.com
> Subject: RE: [Repeater-Builder] Cavity/duplexer connection cables
>
>
>
> Thanks Eric .The uhf diplexer is a 6mc450s and it has been
> tuned to the makers procedure (tuned for the notch and not
> pass).The notches came up with ease around 70 db each side
> and the db loss at the pass frequency was around 1-2 db .I am
> using a hp8921a with the duplex out and ant in
> connections.These mobile notch duplexers are supposed to do
> between 400-520mhz but as you say maybe they are built to
> suit the particular frequency for the client .There are
> plently of them available and they quote they are supposed to
> cover the frequencies.The interconnecting cables cannot be
> changed and are molded into the design of the duplexer. I
> have been able to remove the top screw plate from the one I
> am having problems with and have found one of the insulating
> tubes has a burnt hole through it so a spark of rf could jump
> from the tube to the adjusting screw and has burnt the tip of
> the screw black so this could be the cause of the static and
> loss of power because it was in the TX pass side.I will look
> at making a new insulator tube and test it again . I have
> other flat pack duplexers in use and they work perfectly .I
> have been changing them slowly over to 6LD450s notch
> duplexers because they seem to work better than the mobile flat packs.
>
> Thank You,
> Ian Wells,
> Kerinvale Comaudio,
> 361 Camboon Road.Biloela.4715
> Phone 0749922574 or 0409159932
> www.kerinvalecomaudio.com.au <http://www.kerinvalecomaudio.com.au/>
>
>
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