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My last message was meant in response to Oristo. Forgot to quote it. "Use of 74LVC4066 Quad bilateral switch instead of SA612 mixer is elegant; given square wave Si5351 output, its ideal mixer

It might also be better to redesign the resistance bridge for wider impedance measurement. Current balanced 50 ohm bridge, NanoVNA design, does not have wide range. The FA-VA5 and EU-1KY antenna

I would think that just putting resistors in series with each side of the crystal would raise the impedance enough to unload the Q. I would start with 1 K ohm on each side (for the series

Yes, because of the strong impedance mismatch between the crystal and the VNA there may be some passband ripple. But it is still instructive to see what the passband curve looks like with closely

A thought experiment and an issue with comparison of the single crystal with the matched filter counterpart. A single crystal in series mode is embedded in a 50 ohm system, in this measurement.

Thanks, George, for the FA-VA5 video hyperlink: https://www.youtube.com/watch?v=X8Z7veGV57o Use of 74LVC4066 Quad bilateral switch instead of SA612 mixer is elegant; given square wave Si5351 output,

Here is some information on phase noise on the chip, Si5351A used in the VNA. It is reasonable, nothing extraordinary, however, the loop configured in the VNA may do some noise correction. In any

Sure, I'll try that. I'll try an xtal in its shunt mode, so just a S11 measurement. Then in series mode in which case I should pick up both a S11 and S21 set of values. I assume you measured the xtal

Thanks for info, George. Thats what I was looking for.

Sorry, but gave you wrong reference date for QEX article. It is titled "DG5MK IV Meter, An Accurate Antenna Analyzer" by Michael Knitter in the May, 2017 issue of QEX.

Now try a single crystal, closely scanned/calibrated, near resonant frequency point. It won't be matched to 50 ohms but will still give you a narrow curve. I tried a crystal at 27 MHz and it looked

"You are right. But frankly speaking I do not understand why the spurious do not influence the test results. I am lacking the theory behind." If the system is linear, the harmonics can be separated

BTW the images attached are so compressed that often it is very hard to read any text. Can this be modified by the moderator of the group?

Just by curiosity I made a phase noise measurement of the output signal. For comparison the overlay in the picture is my 10MHz rubidium standard which shows the measurement limits of my system.

You are right. But frankly speaking I do not understand why the spurious do not influence the test results. I am lacking the theory behind.

Here are some plots/data capture.

All good questions and point. Thanks. I shall post my measurement plots. I did both data capture as well as photo shot of the VNA as it looks a bit better on the VNA screen as opposed to the data

No, EU1KY is quite a bit different in any case, you have a limited resolution bandwidth even if it is not apparent as a physical filter circuit. although I think there must be a lowpass filter after

He is implementing a narrow bandwidth filter in the DSP to remove artifacts of the square wave. It is the same procedure used by the FA-VA5 and EU-1KY antenna analyzers. Otherwise the square wave

I may be wrong, but: * is nanoVNA not derived from the EU1KY antenna analyzer? * in which case, mixers basically mix down to DC (no IF) - bandwidth limited by RC networks into ADCs with 5.5 MHz gain