Measure SMA connector - RF Cafe Forums

 Post subject: Measure SMA connector

Posted: Mon Mar 12, 2007 9:13 pm 

I need to measure VSWR and insertion loss of some SMAs from 0.5GHz to 5GHz. Any advice of how to do that? I have access to 8753C, SA 8566B. How do they test SMAs at manufacturers like Amphenol or Tyco anyway?

Thanks
Lanny

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Posted: Tue Mar 13, 2007 4:30 pm 

Do you think put 2 identical SMAs back to back with connection strip (or mechanical sleeve) less than calibration adapter kit's electrical length will solve the problem (take the average of the 2)?

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Posted: Fri Mar 16, 2007 7:45 pm 

Hi,
Can you describe what type of interface do you have on both ends of your SMA connector?

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Posted: Tue Mar 20, 2007 1:53 pm 

Hello UknowWhat,

Are these SMA adapters or SMA connectors on cables?
If they are adapters, are they the same type on each end or opposite type? This is important because if they are opposite type then they are "insertable" and you won't need to account for the extra adapters.

The 8753C NA is perferable becuse it can do both measurement, apply the corrections and calculate the answer in the units you need. It can also be done with the 8566B but you will need extra equipment like a coupler or VSWR bridge for example.

Before a method to do the test can be given we need to know the answers to the first questions in paragraph 1.

Regards,
RFTEjerry
P.S. I could not use the correct terminology because there must be a filter on the forum to sensor certain words so I used "type" instead. I hope you get the meaning.

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Posted: Tue Mar 20, 2007 6:52 pm 

Greetings RFTEJerry:

I'm glad to see that you use the "Preview" button before posting, since that is how you would have caught the censoring of the word s e x. It ends up like this:

*censored*

It is an unfortunate necessity due to the amout of vulgar content posted by vulgar people. The latest trick is posting links to have vulgar images appear in the forum threads. It is a constant battle keeping them cleaned up. My concern is that someone in the workplace will view a forum post and something will appear that could cause trouble for the viewer. Imagine the potential for problems if one of those pictures or a page full of censored words was left inadvertently sitting on a computer screen in a workplace!

Fortunately, within a few months there is supposed to be a major new release of the forum software that has a lot of filtering built in. It's in Beta now, but I don't want to run Beta software on the public forum.

What a sick bunch of people there are in the world that get their satisfaction imposing their depravity on the rest of us. Their methods and motives are no better than other terrorists who loom in a cover of anonimity and prey on the innocent. I would show the worst of them no mercy when caught.

Thanks for your work as moderator of this forum, and note from the example at the beginning that you can actually "fool" the censor system for the cause of all that is good

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Posted: Fri Mar 23, 2007 12:12 pm 

Hi all,

Thanks for the reply. I was so busy lately that rfcafe must be in another planet.

The SMA connectors are panel mounted jack. The VNA test cable interface is APC-7. We do also have precision 3.5mm supplied by Agilent so we can use it as an SMA adapter and calibrate it out.
After some researches and reading an old textbook by Gupta, I think it's doable by building a aluminium text fixture with both SMA jacks mounting back to back, connected through a 50mil diameter brass sleeve and take the square root of the result. I could also improve the characteristic of the connection by insulate it with a 50Ohm seal. Theoretically.

APC-7->3.5->SMA<->SMA->3.5->APC-7

Lanny