Okay, thanks all.
I've obtained proprietory 50 ohm loads and power splitters, so just
need to sort out the throughs, shorts and opens. The obvious question
now is: in respect of throughs and open and shorted terminations, is
the coax length of these relevant? I envisage making up N-type
connectors with say one inch long coax stubs for both open and short
unless there's some problem with this. Is the electrical length of the
coax relevant?
Thanks,
P.