I've been trying to make some NF measurements with an Anritsu MS4622 "scorpion" which says that it has the 6GHz NF Option on the HW options screen, but every time I try and measure I get a Noise Figure overload error. There also seems to be a distinct lack of 28V out of the back port for the HP346B.
I'm wondering if the software is present but some hardware element is not present, although I would have thought the firmware would have detected that.
Photo shows the front of the RF board. I'm wondering if there should be some other modules behind the input modules marked 46720.
Alan