_____
From: [email protected]
[mailto:[EMAIL PROTECTED] On Behalf Of Daron Wilson
Sent: Thursday, January 31, 2008 9:37 PM
To: [email protected]
Subject: RE: [Repeater-Builder] Re: Desense Problem on 222 MHz Repeater
(window filter cannon fodder)
> > I can't imagine why you would want to put a "window filter"
> > between your duplexer and antenna line. There is much more
> > to be gained by putting separate band pass filters on the
> > tx and rx ports.
>
> There can be good reasons for including a window filter with
> a duplexer. Reduction of high powered signals, which are IF
> Images would be one such appplication. Sometimes a plain jane
> duplexer just isn't enough. Sometimes a duplexer doesn't provide
> a DC return to ground, which is nice to have when/where possible.
Let's not shoot ourselves in the foot here. >:)
If you need more selectivity for the transmitter or the receiver then put a
cavity or two on the appropriate port. You get more for your money that way.
Perhaps.but not necessarily. We have a VHF system on a site that is very
noisy and crowded. Separate transmit and receive antennas with about 100'
of vertical separation. We worked with a variety of full size band pass
and notch cans in different configurations but could never clear up some
grunge in the receive side. I installed a DCI 144-148 Mhz window filter in
the receive side before the cans and it shaped right up. Whatever was
getting in was pretty much filtered by this additional window filter, and we
hadn't been able to do it with three band pass filters.
73 N7HQR
<http://geo.yahoo.com/serv?s=97359714/grpId=104168/grpspId=1705063108/msgId=
79015/stime=1201832734/nc1=4025304/nc2=5028925/nc3=5170402>
