AnsweredAssumed Answered

Damaged 3.5mm standard?

Question asked by mattski on Oct 6, 2010
Latest reply on Oct 6, 2010 by Dr_joel
I have two old (>10 years) sets of HP 3.5mm calibration standards, and I tried on two different network analyzers to use them to perform an SOLT calibration up to 18GHz.  One port had a male cable, other port had a female test cable.  On both network analyzers, even if I switched the cables, the test port which used the female standards would show worse results - the phase of the open male cable was much greater than the phase of the open female cable, and it was a much lossier open.  I'm not used to doing coaxial measurements above a few GHz so I'm not sure if I should expect a big difference between the cables because one is male and the other female.

This makes me suspect the female standards were bad, so I checked under the microscope and saw that for both of these sets of cal standards, most of the females have damaged "tines" on the inside of the conductor.  They are all there, but in many cases have been twisted around, as in the picture below.  I recall from microwaves101 that this is a Very Bad thing to happen to cal standards, probably caused by labmates twisting the standards while making connections.

Is this damage likely to cause a bad calibration?

Unfortunately we only have the two sets of 3.5mm standards in the lab, and they are not used very often, so I cannot readily compare against another cal kit.