Hello. I have two calibration kits of the same model. They both pass their pin depth and electrical specifications. However, I tend to get slightly better measurements with one kit versus the other when measuring the same device. If I perform a VNA verification using each calibration kit and compare the results of the 20 and 50dB attenuators, and the airlines, how much difference should be expected? And, is it valid to use an airline, termination, and offset short to measure the directivity and source match of the VNA and deduce that the one that yields the better results is the better calibration kit?
You can use your airline to determine the quality of a load: (see page 178-182 of my book for details)
First connect the load to the test port directly, and do S11, data->mem, data-mem (data MINUS memory), and the level should be -80 dB or so (use 1 kHz RBW, 0 dBm or so).
Then disconnect the load and reconnect it. the level should be below -60 or -65 dB. This tests the connector repeatabilty of the load.
Then connect the same load to the end of the airline, and the airline to the port. Record the envelop of the values. The actual load performance is 6 dB lower than the peaks of the envelop. see if there is a difference between the loads.
Of course this presumes the airline is much better than the loads.