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Ruben,

You didn't mention which sensors and meters you are using: thermistor (432A/487A type) or thermocouple (8481A type). Not that I know the answer in either case, but there's a fairly large difference.

I clean SMA and N connectors using a Q-tip soaked in isopropanol, though ethanol would work fine also. SMAs especially are sensitive to debris on the insulator.

Frequency measurement accuracy is a complicated question. The accuracy of the 8560 series is given in the calibration manual as:

f*DFR_rel + 2N (Hz) + 1LSD where f is the frequency, DFR_rel is the relative accuracy of the reference, N is the harmonic mixing number (depends on f) and 1 LSD is the least significant digit of the reading. DFR_rel depends on option. If you use the GPS as a reference, it's probably around 10^-11, otherwise probably around 10^-7 up to 10^-5.

The mixing number is given in the spec sheet as:
30 Hz to 6.46 GHz: N =1
5.86 GHz to 13.2 GHz: N = 2
12.4 GHz 31.15 GHz: N = 4
31.0 GHz to 50 GHz: N = 8

Basically, the first term is the error from the reference, the second is the integrated phase noise error of the instrument and the 1LSD is the usual least significant digit bobble.

Here is the spec sheet:


Erich