Here is a 9 MHz crystal filter which is matched to 50 ohms. The response is in good agreement despite not re calibrating over the proper passband range; say 8-10 MHz. Instead I used the 50 kHz - 900 MHz cal and reset the stimulus range to cover a narrower passband. It would be best if you cal with prior knowledge the filter center and span and not task the interpolation routine. The update rate between the PC and the COM port on the nanoVNA is fast enough to permit real time tuning of the Z match networks. I set the refresh rate to 800 mS. Alan
