Hi Paul -
ive updated the wiki
I have calibrated after installing NanoVNA-Q many times,
and SAVE->SAVE [0-3] is NOT required after CAL->RESET
RF CALIBRATE can fail for several reasons, but that is not one.
Here are some calibration failures that I personally experience:
1) Immediately after firmware installation,
failure to (by terminal command) `clearconfig 1234` followed by power off/on
2) After `clearconfig 1234` followed by power off/on, failure to `touchcal` and `touchtest`
If touch calibration is off, based on your personal touch style,
then it is too easy for one or more of the OPEN/SHORT/LOAD/ISOLATION/THRU/DONE
presses to NOT be detected. When press is detected, the next button highlights...
Watch for that, retry if not sure.
3) Failure to verify e.g. Smith plot change for each termination change during calibration
- may not get SHORT, LOAD or THRU termination properly connected
4) Connector crimp to coax failure
- I am always calibrating with RG-316 leads, and 2 have failed since July
- Crimp failure may be detected by LOGMAG or other plot change by touching connector
or by SHORT not registering correctly on Smith plot
I do many successful RF calibrations without saving, but still fail 1 of 4 or so, with or without saving.
Oristo