Beware of cheap underperforming clones

As of 2022 there are many badly performing clones on the market. V2/3GHz NanoVNA uses parts like ADF4350 and AD8342 which are costly and clones have been cutting costs by using salvaged or reject parts.

See official store and look for V2 Plus4/V2 Plus4 Pro versions only to avoid getting a bad clone. We have stopped selling V2.2 versions since October 2020, so all V2 hardware that are not Plus or Plus4 are not made by us and we can not guarantee performance.

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Does the Firmware Assume Any Calibration Standard Coefficients?

biergaizi2009 2022/05/07 08:15

Hi all.

I'd like to know that when you perform a calibration using the NanoVNA v2 itself, does the firmware assume any calibration coefficients for the standards by default? I'm using the NanoVNA v2 for some measurements, controlled by the computer, and the calibration is done entirely in my own data post-processing. I'm currently assuming the standards are ideal, with reflection coefficient of 1, -1, and 0, without coefficients for correction. This is adequate for my purpose. However, it just came to my mind that if the NanoVNA v2 itself makes any assumption, there will be a disagreement between the built-in measurements and my computer measurements.


P.S: I previously asked whether the NanoVNA v2 is suitable for CW measurements and the answer was negative, but I ordered one anyway for other measurement tasks.

DiSlord 2022/05/08 03:50

In my last fw version (after v1.2) for V2 i add Calibration Standard coefficients support.
Also it allow work CW mode.

biergaizi2009 2022/05/09 11:38

> In my last fw version (after v1.2) for V2 i add Calibration Standard
> coefficients support.

Could you please clarify your answer? Does it mean that, if nothing is specially adjusted by the user (i.e. using the calibration standard coefficient feature), by default, the firmware calibration routine assumes ideal open, short, and load? I don't care whether the firmware supports any coefficient, I do not use the firmware calibration and do everything in my own post-processing programmatically from raw data. Rather, I'm concerned whether the firmware is doing anything behind the scene that may cause a disagreement in the final data when one compares the default firmware calibration and my own external calibration (for example, I heard that some NanoVNA v1 firmware hardcoded a 50 fF capacitance for the open standard by default in the calibration routine).

DiSlord 2022/05/10 01:18

By default in my fw on measure STANDART for all H / H4 / V2 / Lite:
OPEN = 1
SHORT = -1
LOAD = 0
No any additional correction added (i remove 50pF apply for H/H4)

But after v1.1 for V2 series i add calibration standards coefficients:
- OPEN: C0, C1,C2, C3 and Delay
- SHORT: L0, L1, L2, L3 and Delay
- LOAD: Z0, L. C, Delay
- THRU: Delay
You can input this values, and after V2 apply this corrections for calibration data (now OPEN/SHORT/LOAD not 1, 0, -1)

On CPU connection V2 send RAW data (possible ask calibrated, but by default send RAW)

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