4 cans will do it. Preamp may or may not be of any use depending on noise floor. Your bigger problem is all the noise that a mobile encounters these days. Sometimes it's tough to hear the repeater through all the crap that's out there.
Chuck WB2EDV ----- Original Message ----- From: "NORM KNAPP" <[email protected]> To: <[email protected]> Sent: Thursday, September 09, 2010 3:04 AM Subject: Re: [Repeater-Builder] Wacom WP-639 Duplexer question > 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: [email protected] <[email protected]> > To: [email protected] <[email protected]> > 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: [email protected] >> <mailto:Repeater-Builder%40yahoogroups.com> >> [mailto:[email protected] >> <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of NORM KNAPP >> Sent: Wednesday, September 08, 2010 11:38 PM >> To: [email protected] >> <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: [email protected] >> <mailto:Repeater-Builder%40yahoogroups.com> >> <mailto:Repeater-Builder%40yahoogroups.com> >> <[email protected] >> <mailto:Repeater-Builder%40yahoogroups.com> >> <mailto:Repeater-Builder%40yahoogroups.com> > >> To: [email protected] >> <mailto:Repeater-Builder%40yahoogroups.com> >> <mailto:Repeater-Builder%40yahoogroups.com> >> <[email protected] >> <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: [email protected] >> <mailto:Repeater-Builder%40yahoogroups.com> >> <mailto:Repeater-Builder%40yahoogroups.com> >> <mailto:Repeater-Builder%40yahoogroups.com> >> [mailto:[email protected] >> <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: [email protected] >> <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. >> >> >> >> >> >> >> >> > > > > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3121 - Release Date: 09/08/10 02:07:00
