Wouldn't it be fair to say that a notch duplexer rejects only the
'opposite' frequency in the system while a BandReject duplexer rejects
ANYTHING other than the pass frequency? (within the limits of the
notches)
So, a BandReject duplexer will help eliminating mixing products, while a
Notch duplexer won't. Given the choice, I would always take a BP-BR
duplexer over a notch duplexer.
Joe M.
Jeff DePolo wrote:
>
> > Can someone please explain what the difference is between a
> > BandPass/BandReject duplexer and a BandPass/Notch duplexer?
>
> In our little two-way radio world, the answer is that there is no
> difference.
>
> Technically speaking, a "notch" is very narrow, targeting only a specific
> frequency. A theoretical definition of a notch might include the phrase
> "infinitesimally narrow", but that doesn't exist in the real world - you
> can't achive an infinite Q.
>
> Likewise, as is often seen in other RF endeavors, a "band reject" implies a
> wider reject response, not just a single targeted frequency. For example, a
> band reject filter used in the TV/CATV world might reject a whole 6 MHz wide
> channel, or several contiguous channels.
>
> But the bottom line is that, in two-way, manufacturers seem to use the two
> terms interchangably. So don't lose any sleep over it.
>
> > Also - I just put a new PA online today on my 444.550
> > machine. The duplexer I have is rated at 100W, and the PA is
> > putting about 150W into it -- I was running about 50W with
> > the old PA. (BTW - There is an isolator between the duplexer
> > and the PA.) Will this cause me any grief either now or down
> > the road and if so, in what way??
>
> Quite possibly, yes. Duplexers' maximum power rating is usually a function
> of one of two factors: either its ability (or lack thereof) to dissipate
> heat as a function of insertion loss, or the breakdown voltages of one or
> more of its internal components (such as piston trimmer caps or thin
> dielectric materials).
>
> --- Jeff
>
>
> Yahoo! Groups Links
>
>
>
>
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