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pna-x noise figure for converters 2.4mm E-cal variation

Question asked by rok on Feb 18, 2014
Latest reply on Feb 18, 2014 by daras

I am taking noise figure for converters measurement on the PNA-X. I am using a 2.4mm E-cal on the RF port side and a 2.92mm E-cal kit on the IF port side. The problem is that I get different results with 2 different 2.4mm E-cals, while still using the same 2.92mm E-cal. Both 2.4mm E-cals give roughly the same noise figure waveform shape across the frequency band, but they are offset by about 0.3dB. I also tried a 2.4mm mechanical cal kit and it agrees with the 2.4mm E-cal with the lower noise figure measurement. (only worse by a few hundreds of a dB). So I believe there is something wrong with the 2.4mm E-cal that is giving the worst noise figure result. 

My first question would be what is the largest variation one might expect for the noise figure measurements between 2 different 2.4mm E-cal kits. My guess would be at most 0.1dB. The second question is whether there is a user-side test I can run on the PNA-X on the suspect 2.4mm E-cal kit which might reveal the problem.