John,
If you're sweeping an antenna that's in close proximity to the VNA,
leakage from the cables is probably not going to be a limiting
factor. Other aspects of cable quality (impedance bumps at
cheap connectors, as just one example) still matter. Another
very important aspect of cable quality is stability of the cable's
delay in the face of flexing the cable. If, for example, the cable
is flexed in between measuring the short and open CAL standards,
it can really throw off even single port calibrations.
You're right: really good test cables for VNA work would set you
back more than 10X the price you probably paid for your nano-VNA.
And a decent set of CAL standards goes for around $4k to $5k
last time I looked, which was close to 10 years ago.
I have access to a lab-grade VNA and have been meaning to
take a look at the cables that accompanied my Aursinc nano,
but haven't gotten around to that yet.
Dana
