Bill,
I have the cal. software ( HP BASIC). As you said, it needs a lot of specific HP gear, but I re-wrote it in Python so it can be run on a modern PC with Prologix GPIB USB adaptors. And it is possible to use it with almost any signal generators/power meters/spectrum analyzers.
Further, the 4195A does not necessarily need a full cal; if you had to replace the EEPROM, you can also just do the calibrations that need the EEPROM.
* there are AFAIR two voltage-controlled bandpass filters in the bottom unit. The EEPROM stores the tuning voltage vs. centre frequency table.
* I think there is also an ALC loop in the bottom unit; and the EEEPROM has a table of the frequency dependent output power variations.
Tobias
HB9FSX
