Larry, Eagle is perhaps the best-known manufacturer of RLBs. Go here:
<http://www.eagle-1st.com/prod/pr2/rlb_toc.htm> RLBs made by Eagle range from about $400 to more than $900, depending upon the type of connectors, frequency range, and the precision. There are links on the above URL that take you to the very informative library of application notes. There are other manufacturers of RLBs, such as Hewlett-Packard, Wiltron, Rohde & Schwarz, and Microlab/FXR, but these are more costly and of laboratory quality. Once I bought my HP network analyzer, I put my Eagle RLB on the shelf but will keep it as a backup. Please consider that the RLB is only as accurate as the spectrum analyzer you use with it, so if the analyzer does not have an accurate and stable internal oscillator, you may be wasting your time trying to tune a duplexer with an RLB. 73, Eric Lemmon WB6FLY Quoting "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>: > 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/
