Compared to using a RLB in conjunction with a service monitor (such as an IFR 1500) or a network analyzer, the Bird 43 is cumbersome and time wasting. It will get the job done, but with less accuracy and much more time invested. I'd consider it a minimal effort at tuning a duplexer, not a thorough method at all. And no, it isn't a RLB by the definition.
At 10:35 AM 12/21/2005, you wrote: >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 > > > > Thanks, Robin Midgett K4IDC 615-322-5836 office - rolls to pager 615-835-7699 pager 615-301-1642 home [EMAIL PROTECTED] [EMAIL PROTECTED] http://www.people.vanderbilt.edu/~robin.midgett/index.htm 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/
