Thanks, Stephen. I don't seem to be able to find the user guide for this instrument. I do have the full original service manual, though, which is invaluable in getting the device fully functional again. It was a stretch for me, though. A bit above my pay grade as they say. But at least I did it, it works and I've learned a lot in the process - not about the process of vector network analysis but rather about working on something I'm not familiar with and gaining confidence in so doing.
Jinxie