Re: NanoVNA first impressions: did I just get a bad one? #calibration #nanovna-h_v3dot4 #edy555_nanovna


Peter Ide-Kostic <on7yi.pik973@...>
 

I don't think any nanovna "V1" can work with good accuracy above 900 Mhz,
whatever "flavor". For all my measurements above 300 Mhz, I use another VNA
offering a much better dynamic range.
A nanovna "V2" is what is needed to work above 900 Mhz not a "V1"

On Mon, Jun 15, 2020 at 2:10 PM <iyerak@...> wrote:

Hi! I'm new to this group and just received my NanoVNA-H. I discovered
some issues, and would appreciate the advice of members in this group on
the following four questions. Thanks in advance!

1. A full calibration to the end of the supplied cables and up to the
maximum frequency of 1.5GHz gave me good results when I connected the
short/open (S11~0dB) and load (S11~-50dB) standards to ch0. However, when I
connected the thru standard, S11 was between 15-20dB at most. This sounds
really poor, given that the thru is supposed to be a matched 50-ohm
connector.
2. Measurement of a microstrip double-stub bandstop filter at 1GHz showed
an S21 curve that unnaturally flattens out at about -20dB from
approximately 900MHz to 1.1GHz, rather than dipping down to about -50dB,
which is what full-sized VNAs show.
3. All my measurements show something weird around 900MHz, like a
discontinuity in the curves. I know that the NanoVNA-H switches over to the
3rd harmonic from 900MHz to 1.5GHz and the dynamic range is reduced, but
why shouldn't the curves be continuous?
4. Finally, just a question: has anyone had luck finding the properties
(e.g. capacitances, inductances, phase offsets, etc.) of the supplied
calibration standards, so that they can be entered into NanoVNA-saver?

Thank you!



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