My comment would be that any method that doesn't allow for measuring return loss at the pass frequency is subject to mistuning. In most duplexers, the pass is rather wide and if only pass measurements are being made, then the optimal tuning for input return loss cannot be made accurately. While the pass is fairly wide, the return loss frequency is very narrow and can be optimized only if monitoring the RL as well as the throughput.
Hap Griffin ----- Original Message ----- From: v44kai To: Repeater-Builder@yahoogroups.com Sent: Sunday, June 22, 2008 4:09 AM Subject: Re: [Repeater-Builder] Duplexer tuning with an Oscilloscope Hi Darrell, I never done it, and will like to try it. Can you send me a sketch of the setup, with a brief explanation of your procedure for accomplishing this? Will appreciate it very much Darrell. v44kai.....Joel. ----- Original Message ----- From: "jistabout" <[EMAIL PROTECTED]> To: <Repeater-Builder@yahoogroups.com> Sent: Sunday, June 22, 2008 12:06 AM Subject: [Repeater-Builder] Duplexer tuning with an Oscilloscope > Hi All, > > Just curious if anyone here has used a wide-band oscilloscope (along > with a signal source, of course) for duplexer and/or filter tuning? > > I use an older Tektronix 7904 500mhz scope along with an HP 8640B > Signal Generator and it works great. I can't really measure filter > response, but I can see amplitude changes both large and small very > well, which allows for quite precise tuning. I've tuned a couple of > pass/notch type duplexers and several notch-only units with this setup > and they all work nicely. > > Anyway, wonder if anyone else does this and general comments on the > technique. Thanks! > > - Darrell/KA7BTV > > > > > > > ------------------------------------ > > > > Yahoo! Groups Links > > > ---------------------------------------------------------- No virus found in this incoming message. Checked by AVG. Version: 8.0.100 / Virus Database: 270.4.1/1512 - Release Date: 6/21/2008 9:27 AM
