Hello David,
I mentioned in a much earlier post, I have no idea what is in the firmware definition for the standards supplied with the nanoVNA. In addition, based on the physical description of the standards provided, i.e. the 50 ohm load a pair of 100 ohm chip resistors soldered in parallel, that they may not represent the state of the art! However, if there were a way to measure and characterize them as a entry to the unit, such as a classification table, that would be helpful,
I did measure their 50 ohm load after an independent 3.5 mm SOLT cal on a hp 8753 VNA and found their load standard at 900 MHz was at best 17 dB return loss. Another measurement of a second independent 50 ohm load from Weinschel on the 8753 at 900 MHz demonstrated a significantly better return loss. However, on the nanoVNA the Weinschel showed the same 17 dB return loss.
Is there an issue here? YES!
I might add, folks who use this instrument should consider obtaining SMA connector savers. It will not be long before the poor SMA connectors on the nanoVNA are tainted.
Alan
