What does Error Code 42 on the 8970B Noise Figure Analyzer indicate?

This error is generated when the System Local Oscillator (LO) is not located on the GPIB bus at the address specified via Special Function 40.1.

1. To rectify the error ensure the System LO GPIB address is set correctly and connected to the System Interface Bus (not the GPIB bus). By default the 8970B sets the System LO bus address to 19.
2. Confirm the source's address is set to 19 (at the source). Also, if the LO is an 8360 or 8370 family source, confirm the GPIB language at the source is set to Analyzer mode (not SCPI).
3. If the default System Local Oscillator GPIB address of 19 is not acceptable, modify the address at the source, and modify the setting of the System LO at the 8970B via the keystroke: 40.1 SP (GPIB address) ENTER
4. If a System LO is not being utilized, set then disable the LO via the sequence: 46.1 SP ENTER