Thank you for visiting RF Cafe! Electronics World Cover,TOC,and list of posted Popular Electronics articles QST Radio & TV News Radio-Craft Radio-Electronics Short Wave Craft Wireless World About RF Cafe RF Cafe Homepage RF Cafe in Morse Code Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs Twitter LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes AN/MPN-14 Radar 5CCG Notable Quotes App Notes Calculators Education Magazines Software,T-Shirts,Coffee Mugs Articles - submitted by RF Cafe visitors Simulators Technical Writings RF Cafe Archives Test Notes Wireless System Designer RF Stencils for Visio Shapes for Word Search RF Cafe Sitemap Advertising Facebook RF Cafe Forums RF Cafe Homepage Thank you for visiting RF Cafe!

Testing Circulator / Isolator - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Original posts:

Amateur Radio | Antennas | Circuits & Components | Systems | Test & Measurement


Lamini
 Post subject: Testing Circulator / Isolator
Posted: Fri May 11, 2007 6:03 pm 
 
Lieutenant

Joined: Fri May 11, 2007 5:48 pm
Posts: 3
Greetings everyone.

Ive not new to here as I come here every time I could use some help and use the search feature mostly for antennas/vswr/smithcharts. However, I have not found anything on testing Circulators and Isolators. I have searched here and the net with very little luck, i believe wikipedia had the most info. Not that theory of operation on these items wouldnt hurt me, I am mostly searching on how to test them. Well, if I knew how they operated then I would know how to test them. However, after looking at the spec sheets of circulators/isolators on the net, are they tested by insertion loss?

I have a Motorola R2670 easily available, will this do the job? Its your basic comm test set (for those that dont know), and more. Im not sure on how to test a circulator (ie will this frequency pass with very little amount of reflection?). Im guessing I would use the Duplex function (generate Freq on RF IN/OUT while monitoring Freq on ANT port vs using Tracking Generator (?). THe Freq range supported by the test set is applicable to what I will be working on (make sure the circulator works / passes Freq with very little loss).

Thank you ahead of time. meanwhile i'll be playing with the test set.


 
   
 
Lamini
 Post subject:
Posted: Fri May 11, 2007 6:12 pm 
 
Lieutenant

Joined: Fri May 11, 2007 5:48 pm
Posts: 3
learned some info...

environment is a radio with < 200Watts out to antenna (VHF range). all i gotta do is verify circulator/isolator work, was told a double circulator was in place... whatever that is


 
   
 
RFTEJerry
 Post subject:
Posted: Mon May 14, 2007 10:14 am 
 
Captain
User avatar

Joined: Thu Apr 13, 2006 9:53 am
Posts: 17
Location: Florida
Hello Lamini,
An isolator is nothing more than a circulator with the "final" port terminated in a "perfect" 50 ohm load (or whatever the characteristic impedance is).The purpose of these devices is to direct RF energy in only one direction thus protecting the device connected to one port from reflections from another port "downstream". Both of these devices are tested for 1) insertion loss 2) isolation between ports and 3) VSWR. You can use a VNA or a coupler/PM/Spectrum Analyzer to make the measurements. You don't indicated whether these are stand alone componets to be tested before insertion into a system or as part of a "circuit". I'll assume stand alone. Insertion loss can be tested by simply measuring the power into the device and the power out. The difference is IL. Isolation can be measured by applying power into device, using a coupler on output port 1, terminate output port 2 and measure the feflected power from port 2 on port 1. Continue around the circulator until all ports are tested. VSWR is measured by measuring the reflected power from the port of interest using a VNA or a coupler and PM or spectrum analyzer. I have always had good luck in contacting manufactures of components I have used and asking them what and how they test them.

Good luck,
RFTEjerry


 
   
 
Lamini
 Post subject:
Posted: Thu May 24, 2007 12:02 pm 
 
Lieutenant

Joined: Fri May 11, 2007 5:48 pm
Posts: 3
I forgot to post my results from last week. I arrived to the test location and everything happened naturally. Was your basic Insertion Loss measurement;

0dBm in port 1 = 0dBm into port 2. 0dBm into port 2 to port 1 nothing = everything good. I used the Motorola/General Dynamics R2670 Communications Test Analyzer in Duplex mode to transmit/receive as neccessary with no problems.





Posted  11/12/2012

RF Cafe Software

   Wireless System Designer - RF Cafe
Wireless System Designer

RF & EE Symbols Word
RF Stencils for Visio
Calculator Workbook
RF Workbench
Smith Chartâ„¢ for Visio
Smith Chartâ„¢ for Excel

About RF Cafe

Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2022
Webmaster:
Kirt Blattenberger,
 BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.

My Hobby Website:
 AirplanesAndRockets.com

Try Using SEARCH
to Find What You Need. 
There are 1,000s of Pages Indexed on RF Cafe !

height-line