I am neither a programmer nor trained in electronics, but I am having a great time using my nanoVNA-H4 with my homemade crystal radio. I measure S11 using only CH0, and the results I get for Smith chart, inductance, and reactance seem about right and work well when I use them for things like predicting tuned frequency given a know capacitance.
However, I believe I have no way to estimate Q = X / R for my coils, because R is quite low and may vary between -2 and 5 ohms. That variability may not be all that bad for a $90 instrument, but it can¡¯t be used for Q! I am hoping you EE types may suggest a workaround for getting a decent Q estimate.
Here is a totally made up example of what someone may suggest: "R gets quite high at frequencies way higher than those the coil will be used at. At those high R values, the error is less. Take that number, and ¡°everyone knows¡± equation XYZ for skin effect is quite accurate, so use equation XYZ to back-calculate R at lower, practical frequencies. Now you can estimate Q reasonably well."
