Re: Performance of my nanovna V2 clone - return loss of port 2 seems much too high ?


Peter Ide-Kostic <on7yi.pik973@...>
 

Hello,

Thank you for your anwer

Ok, please find below the same test but done without any cables on port 1
and only a through cable to connect to port 1 and port 2. I have also used
400 points to get a clean accurate trace with as little noise as reasonably
possible.


=> At 1.5 Ghz; the return loss on port 2 is still significantly too low
(15.5 dB vs 20dB) expected, *so no changes*

=> At 3 Ghz, the return loss has improved significantly, *it is now 14.7 dB
which is a bit better than the 13dB specified officially.*

=> At 2.33 Ghz, the return loss is 11.7 dB is which is much too low, it
should be minimum 13dB according to the specifications


[image: image.png]


*Conclusion*: my measurements and yours simply confirm that the return loss
on port 2 of my nanovna 2 clone is unfortunately not as good as the one
of your genuine nanovna V2 model <https://nanorfe.com/nanovna-v2.html> .
This is the confirmation that I wanted to have (thanks for your help). I am
not saying all the nanovana V2 clones systematically under perform on port
2 the return loss, but on the other hand, if I have the issue then other
clown owners may have it too (quite common sense really). It will not
prevent me from sleeping at night, but at least I know....

Kindly note that the quality of the calibration loads and of the SS405
cables that I used for this test are perfectly OK.

Thanks
Regards
Peter

On Mon, Aug 17, 2020 at 8:47 PM <@switchabl> wrote:

Peter,

I have attached a measurement of port 2 return loss from my NanoVNA V2,
bought from tindie. This one seems to be meet the specs (-20.3dB @1.5GHz
and -15.5dB @3GHz).

There is also significant ripple on your measurement. It looks like your
calibration is bad and you have significant residual source match error (or
possibly your cable is bad, but less likely; since you are calibrating
directly at the port 1 connector, you are measuring the cable as well). So
I would take the results with a grain of salt. Mine is not perfect either,
but it looks a lot less bad.



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