The useful answer: Calibrate a NanoVNA at the measurement reference plane with the exact frequency sweep and appropriate open, short, load, and through standards required by the measurement.
What changes in real operation
Calibration removes systematic errors only from the calibrated path and range. Adding an adapter or feed line afterward moves the reference plane unless its effect is deliberately included or de-embedded.
The shortcut that causes trouble
A saved calibration can look valid while covering the wrong span, port, cable, temperature, or connector arrangement.
Put it into practice
Set the final sweep, let the instrument stabilize, clean connectors, attach each standard without twisting the cable, complete the calibration sequence, save it, and verify with a known load before trusting antenna data.
Practical boundary
Use current equipment instructions, battery and controller limits, measurement references, operating rules, and observed propagation. Planning values and propagation labels are not guarantees.
