Coax Cable Test Help - RF Cafe Forums

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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

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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BSEE - KB3UON

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