On 9/8/2010 6:11 PM, RichardK wrote: > 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.
The Wacom WP-639 is insufficient for 100 solid state watts, unless you run a GE MASTR II PLL exciter and no preamp. You will either need to replace the duplexer with another unit capable of properly isolating 100 solid state watts, add additional filters, change to a less noisy transmitter and amplifier (tubes are better - no I'm not kidding). Kevin Custer - W3KKC
