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The NanoVNA V2_2 image(S parameter) always abomoral and cannot be corrected by cailberation.


13515474300 2021/01/06 04:23

Hello everyone!  My NanoVNA's  smith circle always shows ellipses and cannot be corrected by cailberation. Certainly that my caliberation option is correct. When I connect to PC,the viewer shows the same situation. Now I wonder that one or some components in it is broken? if its,which component should I replace? The version is V2_2 and  I attached pic(just cable and vna.nothing else attached) follow. Thank U again for tap in and give me an answer! ! !

barnc4br 2021/01/06 06:25

With a cable attached, I get similar results. A cable is not amorphic. You are looking at it over a wide freq range which is why it is going in circles.
Disconnect everything.

ok1vaw 2021/01/06 08:41

If you want to see, what is on the end of the cable, you have to calibrate at this plane. Try to put a picture when you put short on the end of the cable. I suppose there are multiple discontinuities (adapters or similar). Try to look at TDR and you should see, in which distance  the disturbances are.
OK1VAW, Vojtech.

13515474300 2021/01/06 19:54

ThankU for answer,I've tested a same filter ,and the S parameter performance tend to be totally different between my desktop and NanoVNA shows.the later just cannt be figure out cause the serrated S11 and S21 line, pics are follows.

13515474300 2021/01/06 19:57

ThankU for answer,I've tested a same filter ,and the S parameter performance tend to be totally different between my desktop and NanoVNA shows.the later just cannt be figure out cause the serrated S11 and S21 line, pics are follows.

OwO 2021/01/07 12:10

The image in your first post looks like there may be some damage to the
rf switch U551 (mxd8641) or the baluns. Check for broken wires on the
balun and maybe try replacing U551. The circles should look a bit more
round.

On 06/01/2021 20:23, 13515474300@163.com wrote:

13515474300 2021/01/06 22:37

Roger that . I'll try to replace it . SO APPRECIATE !!

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