It turns out there a a few essential parts missing from the VNA I bought. Nothing too serious, but mainly some RF interconnects (patch leads) that go between the VNA and the transmission/reflection test set. These are three leads of 24" and one of 34" all terminated by N-type (male) plugs. The length of these cables is critical to preserving the phase relationship of the signal under examination, it seems. Now I can't find any on E-bay or elsewhere, so my first inclination is just to make them up myself. But is that going to be problematical WRT subsequent measurement errors? How critical is the electrical length quoted and what's the best method for attaching the plugs so as to preserve Zo so far as possible? Thanks, p.