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!
Copper Mountain Technologies (VNA) - RF Cafe
Amplifier Solutions Corporation (ASC) - RF Cafe

About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    Kirt Blattenberger,


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 typing 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:


Anatech Electronics - RF Cafe

Amplitude Match - 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

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Systems

-- Test & Measurement

 Post subject: Amplitude Match
Posted: Tue Oct 17, 2006 8:49 am 

Joined: Fri Sep 29, 2006 11:05 am

Posts: 4

Ok guys, here's another one....

I've been asked to perform a "Amplitude Match" between frequencies on a batch of 4 coax cable assemblies.

What is Amplitude Matching ? How would you perform this on a VNA ? :oops:

 Post subject: Amplitude Match
Posted: Tue Oct 17, 2006 10:43 am 
User avatar

Joined: Fri Feb 17, 2006 12:07 pm

Posts: 268

Location: London UK

I guess it depends to some extent on what is implied by "assemblies". These could be quite complex, or just individual lengths with a connector each end.

In the latter case, different cable types will have different dispersion characteristics of the loss vs frequency response.

If you set up a VNA to display S21 across the range of frequencies asked for, there you have it: compare the curves.

If you have a complex assembly with for example power splitters, you would have to compare port A on one with port A for the others, and go on doing this for the other ports, with all other ports correctly terminated.

 Post subject:
osted: Tue Oct 17, 2006 10:56 am 

Joined: Fri Sep 29, 2006 11:05 am

Posts: 4

Thanks for the reply !

This is a simple coax assembly with 1 connector on each side.

So I'm looking at a S21 measurement. Take the first one, measure it and save it to memory and compare the rest vs. that first one. The difference would be the amplitude difference with the first being the baseline.

Format would be Logmag ?

So it looks like I'm looking at an insertion loss difference between cables at a given frequency span ?



 Post subject:
Posted: Tue Oct 17, 2006 1:28 pm 
Site Admin
User avatar

Joined: Mon Jun 27, 2005 2:02 pm

Posts: 406

Location: Germany


Yes the format should be Log Mag.

You should measure the S21 for each cable in the given frequency range and compare the obtained S21 curve vs. the frequency.


Best regards,

- IR

Posted  11/12/2012

RF Electronics Shapes, Stencils for Office, Visio by RF Cafe

RF Cafe Visitor Comments on News, Articles, System, Design, Components, etc.

Please e-mail your comment to me (Kirt B.), and I will post it here for you - no computers involved!

1 - Your participation will be greatly appreciated. - Kirt B.

Berkeley Nucleonics Academy RF Boot Camp - RF Cafe
Innovative Power Products Passive RF Products - RF Cafe

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

These Are Available for Free