What does Error Code 22 on the 8970B Noise Figure Analyzer indicate?

The Keysight 8970B/71B/71C Noise Figure Measurement Operating Manual specifies the error code as: "Current RF attenuation not calibrated".

This error is generated when input to the analyzer from the device under test (DUT) exceeds the current range setting of the 8970B.

To rectify the error, increase the attenuator range utilizing Special Function 32.x SP.

Error 22 can also appear due to DUT's local oscillator (LO) feed thru. If you suspect LO feed thru as the culprit, use a spectrum analyzer to confirm this condition. Then use a filter to remove the LO feed thru.