Right you are, Chuck! I have one of those Sinclair R-106G, six-cavity low-band duplexers in my garage. Both it and its similar, eight-cavity version are in a heavy steel cabinet that measures 18" deep, 22" wide, and 67" tall. The performance of the Sinclair six-cavity duplexer is about the same as the Decibel Products "water heater" duplexer that uses four cavities, each about 11" in diameter and five feet tall.
73, Eric Lemmon WB6FLY -----Original Message----- From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Kelsey Sent: Thursday, October 02, 2008 5:07 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] LMR-400 Cable I suspect that he has notch cavity resonators. Each can is about two feet tall, more or less. So, while eight of them take up some space, they are not likely as large as you envision. Chuck WB2EDV ----- Original Message ----- From: [EMAIL PROTECTED] <mailto:rertman%40ix.netcom.com> To: Repeater-Builder@yahoogroups.com <mailto:Repeater-Builder%40yahoogroups.com> Sent: Thursday, October 02, 2008 7:14 PM Subject: Re: [Repeater-Builder] LMR-400 Cable Tom, With 65 feet of cable, your feed line is very close to a resonant length at 6 m. Actually about 3 wavelengths. If you have enough extra coax length, try winding some of it into a coil and see if that reduces your desense problem. Also, make sure your antenna is a good impedance match to your transmitter/duplexer impedance. A 6-cavity duplexer on 6 m has to be a HUGE duplexer and I suspect that's where your problem is. You have to have a VERY precisely tuned duplexer that provides at least 85 dB of isolation between the XMTR and the RCVR. 73, Dick W1NMZ
