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 <Repeater-Builder@yahoogroups.com> To: Repeater-Builder@yahoogroups.com <Repeater-Builder@yahoogroups.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@yahoogroups.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> 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.
