The nanovna wiki recommends for calibration:
"Connect cables to the CH0 and CH1 ports, connect the cables with the through
connectors, and execute CAL CALIBRATE THRU."
Is there any particular reason not to use just one of the two included cables
connected from Ch0 to Ch1 without using the through connector
1) frequently connecting and disconnecting directly to nanoVNA's rather fragile connectors
accelerates wear and reduces operational lifetime
2) ANY changes between calibration configuration and subsequent measurements compromises results (AKA invalidates them)
- VNA simply compares so-called scatter values to those made during calibration,
then makes approximate calculations to estimate network values.
Because I'd like to chop one cable
Try calibrating with one cable, then measuring with both (or vice versa)
to approximate the amount of error induced for your application.
That will at least be frequency dependent,
so first constrain the measurement frequency range to that of your application.
rather than buying another cable and connectors
SMA cables have finite useful lifetimes; plan on needing replacements in any case.
Oristo