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


Peter Ide-Kostic <on7yi.pik973@...>
 

Any one with bad return loss on port 2 (less than 20dB) at 1.5 Ghz ?

On Sun, Aug 16, 2020 at 11:18 PM Peter Ide-Kostic via groups.io
<on7yi.pik973=gmail.com@groups.io> wrote:

Thank you for your reply

1) Please find below the trace between 1.4 and 1.6 ghz, of course there no
change (as expected)

[image: image.png]
2) The cables are fine I am sure, they are quality SS405 cables of 25 cm

3) To make a long story short, it is the owner of the Aliexpress shop
himself who informed me that he could no longer deliver the genuine model
<https://nanorfe.com/nanovna-v2.html#> that I had initially ordered in the
April time frame as he had switched supplier. I do not want to enter into
details but I was quite lucky with this specific transaction on aliexpress,
I waited a very long time (with at least 3 different shipping attempts) .
When the device finalmly arrived it had been damaged by transport . The
seller then simply offered me to send me the models coming from his new
supplier which I have accepted.

On Sun, Aug 16, 2020 at 10:55 PM CT2FZI <ct2fzi@...> wrote:

Did you calibrate from 1.4GHz to 1.6GHz and tried to measure it again?

Did you tried using another cable?

Why you say it's a clone?

Cheers

A domingo, 16/08/2020, 21:48, Peter Ide-Kostic <on7yi.pik973@...>
escreveu:

Hello,

I bought a nanovna V2 <https://nanorfe.com/nanovna-v2.html> on
Aliexpress
a
while ago. When I received it, I realized that it was a clone which I
did
not expect, but ok, I managed (as usual)

I then checked the performance vis a vis of the official nanovna-v2
specifications <https://nanorfe.com/nanovna-v2.html#specifications> .
Fortunately, on the positive side, there was no problem regarding the
S21
dynamic range and regarding the S11 noise floor that both met the
nanovna
V2 specifications. However I was a bit puzzled to discover that the
return
loss of port 2 of my clone was unfortunately much higher than what is
officially specified....

official return loss specifications for port 2
20dB at 1.5 Ghz, 13 dB at 3 ghz

my measurements after calibration (see picture)
15.7 dB at 1.5 Ghz and 9.5 dB at 3Ghz

I wondering if
- I am doing something wrong the way I did this measurement
- if I am the only owner of a clone with this specific performance
problem
on port 2
- if owners of the genuine nanovna V2 also have the performance issue
- what is the value of the attenuator that you possibly use on port 2
during calibration to compensate for the sub-optimal return loss (I use
between 6 and 12dB depending on the accuracy I need and the dynamic
range I
am willing to sacrifice)

Thanks for sharing your return on experience regarding this issue

[image: image.png]







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