Negative resitance for S11 port antenna measurement

[kelogs]

Hello,

v0.7.3 on Windows;

Already had my nanovna calibrated in two range: 30 MHz around 315 and another 30 MHz around 434; used an average of 10 sweeps with ~saver which has produced some partly negative values for resistance - measured two (almost) identical antennas, without any in- ~saver calibration. I can say for sure that nanoVNA did not report any negative resistances.

Having seen the failure, i have then set an interval from ~225MHz to 525MHz, some ~300 points, calibrated inside ~saver, remeasured the two antennas with generally different results, but still having ranges of frequency where the resistance was again negative. I have not properly checked what the naonoVNA was reporting on its screen for the frequency range.

What am i doing wrong ?

Thanks!