On 10/3/21 5:30 PM, Roger Need via groups.io wrote:
From what I understand you are resetting the cal in the NanoVNA before connecting to NanoVNA Saver. When calibrating with the Calibration Assistant in the PC program NanoVNA Saver you should already have the NanoVNA calibrated over a range larger than the range you want. This was made clear by the the original author, Rune, in a post when he first released NanoVNA Saver. You can search the group for his post.
I'm not so sure about that.? The interface (over the USB) doesn't expose any way to know whether the nanovna is sending calibrated or uncalibrated data to NanoVNA-saver. The data command with arguments 2,3,4,5,6 allow dumping the calibration coefficients in use, so maybe you could infer whether the results returned by data 0 or data 1 are calibrated or not.
Therefore, the key is that the nanovna is in a state that matches the state it was in when the cal was done with NanoVNA-saver. You could "stack" calibrations, for instance.
In general, though, the cal tables in the nanovna are for the 101 data points (on the base unit), with interpolation used for frequencies not in the table. NanoVNA-saver, though, can store calibration tables with arbitrary numbers of points (it's using scikit-rf's implementation of calibration)
I would argue, then, that you should "reset" (i.e. remove) the calibration on the NanoVNA (since that's a known state) before doing the cal on NanoVNA-saver.
