So no more need to trim cable length manually. Playing around with this instrument, I came across a possibility in the FPC itself to compensate electrically for any cable length differences, both positive and negative, and even a setting to do this fully automatic. In several (excellent) reviews of the Rohde & Schwarz FPC1500 spectrum analyzer, like here and here, considerable attention was paid to the calibration procedure, the electrical length of calibration units, and attempts to make homebrew test cables of a precise, calculated length so that the reference plane would be exactly in the right spot for specific chosen connectors or components.
