•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<
Job Board
About RF Cafe™
Copyright 1999-2015

Coax Cable Test Help - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.

 Post subject: Coax Cable Test Help
Posted: Fri Sep 29, 2006 11:11 am 

Joined: Fri Sep 29, 2006 11:05 am
Posts: 4
Hey everyone !

I have a cable assembly that I would like to get some test data on. Instead of the usual Type N to Type N, I have a daisy chain of Type N to Type N "Tee" to Type N. I can connect to 3 locations but my VNA only has 2 ports. What could I do to test this assembly for an accurate VSWR or IL measurement ?


 Post subject:
Posted: Fri Sep 29, 2006 4:03 pm 
Site Admin
User avatar

Joined: Sun Aug 03, 2003 2:02 pm
Posts: 476
Location: Erie, PA
Greetings TomCalver:

You should be able to terminate one arm of the assembly in a calibrated 50 ohm load (since that is what a 3rd VNA port would present) and test two ports at a time.

I assume you realize that your described configuration will present 25 ohms (assuming you are using 50 ohm cable) to all ports in the assmebly since each port will "see" two, 50 ohm impedances in parallel.

- Kirt Blattenberger :smt024
RF Cafe Progenitor & Webmaster

 Post subject:
Posted: Fri Sep 29, 2006 4:21 pm 

Joined: Fri Sep 29, 2006 11:05 am
Posts: 4

Thanks. That's about what I figured but I just wanted another opinion.

The 25ohm impedance never occured to me. I am using a 50 ohm cable but I'll have research this a bit more.

Everything seems to be matching up on the assembly. The test results are horrible but at least I can see a bit more of what's going on.

Thanks again.


Posted  11/12/2012
Custom Search
More than 10,000 searchable pages indexed.

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeKirt Blattenberger... single-handedly redefining what an engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem!
(Seize the Day!)

5th MOB: My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website