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It seems that CH0 output also has impedance about 40 Ohm. So, it's better to use two 10 dB attenuators. One on the CH0 and the second on CH1.

The source may be DC-DC convertor. Try to disconnect external power from NanoVNA, is it still present?

I think noise may come from DC-DC converter used in battery charger. Because there is noticeable higher noise when external power supply is connected and this noise is not come through cable. It is

I opened the nanoVNA and connected the line in of a good USB audio device to the reference SA612. But as I did not dare to do two connections the unbalanced signal had a lot of noise. And there were

Hello, Allow us, please, to point out that to be possible to the slightest a comparison between measurements regarding nanovna and/or vna, these measurements should be accompanied by an estimation of

does only scalar measurements

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Ouch! Bear Burt, K6OQK -- Sent from my Android thingamabob with K-9 Mail. Please pardon the spelling errors as the dog can't spell so good.

Analog devices has a bridge and detector IC ADL5920, is this useful. It goes from 9kHz to 7GHz.

Caution is the keyword. FWIW I heard long ago that nylon underwear can generate 3000 volts. Bear Albrecht W5VZB New Mexico

Bruce, This link might interest you, http://www.reeve.com/Documents/Articles%20Papers/Ferrite%20Beads/Reeve-Hagen_FerriteBeads_P1.pdf . It describes a fixture and procedure for measuring ferrite beads

Just so I understand, would I connect only the outer shield to the center pin of the two ports, leaving the center of the coax floating unconnected?

These peaks are from spurs of the SI5351 output so they move with the IF frequency and happen at 1kHz intervals. You see them (although lower) also for the 8kHz and 12kHz harmonics of the IF The lower

Hi Alan, the measurements lower limit is given by the phase noise of the SAs oscillators. HP Application Note 270-2 "Autometed Noise Sideband Measurements using the HP 8568A Spectrum Analyzer" shows

Erik, I re-ran it at 1.2GHz, which will correspond to 240MHz. I also changed the offset to 4KHz. Here are the results: [image: image.png] The 1KHz peaks are still there (and unrelated to the IF

I've separately emailed my results having added windowing to the FFT signal. While my results are much improved f

I tested windowing and that does not make a big difference as can be expected in this case where the stimulus is fully controlled What is worrying me are the multiple peaks you get 1kHz apart next to

Erik, The FFT assumes that you have a perfect fit of the (co)sinus in the sample Spot on! I applied the blackman windowing function to the 1.29GHz output (the worst frequency), and the result is much

To get a better CH1 input impedance I recommend to use a 10dB attenuator possibly with a 10dB amplifier when above 300MHz

Indeed, that is what I plan to do with my own build VNA using (almost) the same HW as the nanoVNA Will let you know once done