Hi Carlo,

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you would need more details on what you think seems abnormal, more pictures would be helpful.

It is difficult to know from the calibration constants table alone if you have a problem with your 8590A.

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However, I notice that some correction values ??for the input attenuator are high, there is probably a problem, but it would be necessary to check it to be sure.

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So, if you have noticed that there is frequency drift, this is normal, if the Spectrum respects the specification here.

For a hp8590A, frequency precision is ±5.1MHz.

Frequency stability, after 2 hours warmup and 5 min after setting center frequency, is about 50kHz/5min.

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Yves

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