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Coax Cable Test Help - 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


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

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 ?

Thanks,
Tom


 
   
 
Kirt Blattenberger
 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.

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

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

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.

Tom




Posted  11/12/2012

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