Warning about NanoVNA clones and comparison with Siglent VNA

[cgroen]

FWIW, I did a test on my R&S ZNLE-3 (calibrated with ZN-Z150), 1600 points, BW 100 Hz, average of 100 (only completed 49 scans), 1 MHz to 3 GHz.

[joeqsmith]

And of course, with these low cost VNAs you have a squarewave drive.  Another can of worms....

i think designer already figured it out and dealt with its shortcoming in IF...

I think my comment went over your head.  The designers are not going to know how the drive signals shape interacts with the circuit being tested.  It was the whole point of showing the effects the squarewave causing the amplifier stability issues during the video. 

I watched your 1st video.  While easy enough to follow along, I was really hoping for you showing a lot more than just a couple of antennas and filters.  Maybe consider a detailed review at some point once you have learned more about it.

imho its enough to show one example that its broke to prove that its broke...

From the original description, I was expecting more. 

I did a small comparison of the three instruments in real-world applications (antenna S11 testing and filter S21 testing)

The biggest takeaway is that the cheap clone produces measurements which are drowned out by its own noise, presumably due to poor shielding of the different sections.

[points2]

Thanks to joeysmith & the bootloader for these comparison btw nanoVNA vs Siglent : interesting to see how close they are regarding the amplitude (dB) !...

I'm wondering :
if we plot a derivative of measurement , like the GroupDelay (DUT could be a component, MLCC X7R for instance, something "noisy" around its SRF)
=> do we have the same results => perfect match btw nanoVNA & Siglent ?
or such a derivative parameter enables to see clearer differences in measurements btw these 2 devices ?
Thanks