The Bird Model 43 is a typical RLB. You can also use a network analyzer. Dick
----- Original Message ----- From: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]> To: <[email protected]> Sent: 21 December, 2005 08:20 Subject: Re: [Repeater-Builder] Duplexer tuning with Return Loss Bridge Who makes a Return Loss Bridge? Any idea of the approximate cost? LJ -----Original Message----- >From: Eric Lemmon <[EMAIL PROTECTED]> >Sent: Dec 21, 2005 7:42 AM >To: [email protected] >Subject: Re: [Repeater-Builder] Duplexer tuning with Return Loss Bridge > >Gary, > >A return loss bridge (RLB) is an extremely useful tool for tuning the >pass function of a BpBr duplexer. That's because the bandpass response >of each cavity in a BpBr duplexer is very subtle- nothing like the peak >you will see in a bandpass-only cavity. Even when three BpBr cavities >are in series, the bandpass response is rather wide. > >An RLB allows any good spectrum analyzer to emulate the reflection >capability of a vector network analyzer to a sufficient degree that >bandpass tuning can be much more precise. Instead of viewing the >transmission bump, you can view the reflection notch- which is very >sharp. With such a clear indication of the bandpass tuning, the cavity >can be tuned within a few kHz of the exact pass frequency. > >It is essential that all interconnecting cables and connector cables be >of very high quality, and the spectrum analyzer's reference oscillator >be on frequency. It takes some practice to use an RLB correctly, but >it can allow you to tune a duplexer with remarkable precision. > >73, Eric Lemmon WB6FLY > > >Quoting [EMAIL PROTECTED]: > >> >> Gentlemen, >> Will be starting a new science project setting up Wacom 641 on 2 >> meters. >> Have a Rohde & Schwarz monitor receiver with S meter, DB pads, dummy >> loads >> etc. Plus an IFR 1500. But I see comments on a unit called a 'return >> loss >> bridge' for the IFR. How important is this return loss bridge and >> what is it's >> claim to fame? Do I really need one? Also have an old HP 8554B Spectrum >> Analyzer. >> Thanks, >> Gary K2UQ >> >> >> > > > > > > > > >Yahoo! Groups Links > > > > > > Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
