Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering magazine articles Engineering software Engineering smorgasbord RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine USAF Radr Shop Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Thank you for visiting RF Cafe!
Innovative Power Products Passive RF Products - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe
 

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024

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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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

Copper Mountain Technologies (VNA) - RF Cafe

VSWR Calculation - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts.

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster

jaryi4pora
 Post subject: VSWR Calculation
Posted: Wed Jun 15, 2005 9:34 am 
 
Lieutenant

Joined: Wed Jun 15, 2005 9:12 am

Posts: 1

I am trying to figure out what the output VSWR of a microwave modem assembly will be. There is a Freq Conv with an output VSWR of 2.0:1 then a cable to a switch and another cable going to the egress. Cable VSWR is 1.22:1 and switch VSWR is 1.5:1. If I want to know what the output VSWR at the egress will be, how do I calculate this. This isn't something I can measure on a VNA.

Thanks for any help


 
   
 
Joe
 Post subject: VSWR
Posted: Fri Jun 17, 2005 2:54 pm 
You need a lot more information to calculate VSWR. Full S Parameters, magnitude and phase, are used to calculate the cascaded response.

As a rule of thumb, the VSWR due to the interaction of 2 connected devices can vary between the product of the 2 VSWR's max and the quocient of the 2 VSWR's min. For example connecting a 2.0:1 device with a 1.5:1 device can yield a 3.0:1 (2.0x1.5) worst case if the reflected waves add in phase or a 1.33:1 (2.0/1.5) best case if the reflected waves are 180 degrees out of phase. If you are incredibly unlucky, the components you described may yield a worst case VSWR of 4:1 at some frequency.

The cables will effect the VSWR in several ways. Long cables will allow the phase to vary greatly and cause a large variation in VSWR over the bandwidth. It will add ripple to the response. The loss of the cables will actually improve the VSWR by attenuating the refleted waves.

Measuring the VSWR can be done the same way that the frequency converter is measured using load pull techniques.

Posted  11/12/2012

KR Electronics (RF Filters) - RF Cafe
RF Cafe Sponsors
RIGOL Technologies (test equipment) - RF Cafe
RF Superstore (RF Components) - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free