Oh drat! I thought I was getting away with something.... :-) I am about to start on a 6m mastr ii with 1 meg split. It is a 110 watt cont duty station I am converting to a repeater. I don't think the exciter is a pll, way too many cans on the board and small icom.... About how much isolation will I need there? I don't know if I have a preamp for this one or not... But if I do, I would try to run it. 73
----- Original Message ----- From: Repeater-Builder@yahoogroups.com <Repeater-Builder@yahoogroups.com> To: Repeater-Builder@yahoogroups.com <Repeater-Builder@yahoogroups.com> Sent: Wed Sep 08 23:08:38 2010 Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question The PLL exciter is why you're having such good success running a 4-cavity duplexer. If you had a PM exciter, chances are you'd be experiencing desense. The PLL exciter produces about 22 dB less noise at 600 kHz offset, reducing the noise supression requirement of the duplexer by a like amount. See: http://www.repeater-builder.com/pdf/GE_Isolation_Curves.pdf The OP also mentioned he was using a preamp - that's not helping his situation either. Even with a good receiver he's probably on the edge of crunching it with only a 4-pack. Personally, I'd never run a preamp with nothing but a 4-cavity duplexer on 2m, but if it works for you, God bless... A Q202G gives more isolation than a WP639 from what I've seen/measured, in part because the cavities are larger diameter (I think they're 7" versus 5"?). --- Jeff WN3A > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > [mailto:Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of NORM KNAPP > Sent: Wednesday, September 08, 2010 11:38 PM > To: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > Subject: Re: [Repeater-Builder] Wacom WP-639 Duplexer question > > > > I got a set of 4 sinclair cans, like a Q202g on a GE mastr II > running 100 watts with pll exciter and GE preamp with no > desense. Antenna is roughly 300' away fed with LDF7-50A. Is > this a miracle or typical? > > ----- Original Message ----- > From: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> > <Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> > > <mailto:Repeater-Builder%40yahoogroups.com> > > To: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> > <Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> > > <mailto:Repeater-Builder%40yahoogroups.com> > > Sent: Wed Sep 08 20:10:44 2010 > Subject: RE: [Repeater-Builder] Wacom WP-639 Duplexer question > > > > I'm not surprised- you're asking too much of a duplexer that > has four 5" > cans. According to my CommShop program, a duplexer with an 80 > dB spec is > more suitable with transmitter power in the 10-15 watt range, > assuming a > solid-state PA and a receiver sensitivity around 0.35 uV at > 12 dB SINAD. On > a 100 watt repeater, I'd expect something like a WP-642, > which has six 8" > cans. BTDT, got the T-shirt and mug... > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> > [mailto:Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of RichardK > Sent: Wednesday, September 08, 2010 3:11 PM > To: Repeater-Builder@yahoogroups.com > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> > <mailto:Repeater-Builder%40yahoogroups.com> > Subject: [Repeater-Builder] Wacom WP-639 Duplexer question > > Good evening, our club has a Wacom WP-639 four can duplexer > as part of our > repeater system. Input Fq is 147.915 and Output Fq is > 147.315. We have a > 600kHz (+) offset. Very simply, our main problem is when we run the > transmitter at full power 100 watts, there is a HUGE desense > on the receive > side of things. When we drop the transmitter power level to > around 20-50 > watts, the receive side opens WAY up to a large area where > people can get > into the repeater. As we begin to bring up the transmitter > power, "white > noise" begins to appear and the receive side starts to > desense again. All > the cables have been switched to double sheilded cables and > all the same > wavelength in length. We have the duplexer seperated & > sheilded from the > transmitter & preamp parts. We have not replaced the antenna > feed coax with > double sheilded coax yet. Antenna is a Hustler G7 atop a 55' > mast. The > duplexer was retuned just over 1 year ago. Any suggestions as > to what we > could look into next? Some of us believe the problem is with > the tuning of > the duplexer receive cans. Thank you very much. > > > > > > > >
