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Hello all, I was going to place an order for the NanoVNA-F today and the link that I have for the BH5HNU version is down. I would like to buy from a reputable source and I know that huygen is the developer. So can anybody advise me where to buy the genuine article?

Regards

Conrad PA5Y

#78: on the measurement of s-parameters using the [LeastVNA] only

- 12 November 2019 - /g/nanovna-users/message/6912 -

Hello,

Allow us, please, to inform you that we just uploaded the (indirect)
"measurements" of S11, S12S21, S22 of an unknown 2-port connected to the
[LeastVNA], as well as the (indirect) "measurement" of GL of an unknown
1-port connected to this 2-port, at:



where:

s, l, o and S, L, O are the [LeastVNA] measurements at the Virtual Port of
[LeastVNA], when the SHORT, LOAD, OPEN "standards", 'standards', or
Standards having Nominal Values -1, 0, +1 are connected at the Load Port of
[LeastVNA] and at the Load Port of the connected 2-port, respectively, while G
is the [LeastVNA] measurement of the GL connected to the same Load Port of
2-port.

Notably, only one-port reflection measurements are involved.

Sincerely,

gin&pez@arg

:78#

450mAh is... Not suitable for NanoVNA
1. Stand-by draw
2. Charge circuit pushes over 1A( over 2C rate )

My battery already swelled( PCB/LCD curved slightly )

Fine under Ubuntu 19.10 and Mate desktop.
Also never could get it to run under XFCE4.

On my Mint system there was a 3.7 lite package that would install alongside 3.6 and leave? 3.6 as the default version.? nanoVNA-saver worked fine with that package and it didn't mess up other python apps.

Works fine here on Linux Mint 19.2 amd64 with python 3.7 per instructions here...



Note nvna-s requires python 3.7. Not earlier versions.

Looks like some good advice here...



for troubleshooting this problem.

You could start with

$ export QT_DEBUG_PLUGINS=1

and see what that tells you.

Doesn't work on my Linux Mint 18.3 cinnamon with Python 3.6.
Python has to be updated to 3.7. I tried that before, but other apps stopped working then. So I rolled back to 3.6

Carsten

This is the VNA I am working on. It has the EU1KY bridge (based on a RF
choke) and not the divider bridge.

Among its advantages is that it directly samples the IF signal on the clock
so that a high amount of averaging can happen even in the presence of
SI5351A jitter.

It will hopefully be available soon, and not much more than the NanoVNA,
and including a fixture for component testing.

On Sun, Nov 17, 2019 at 10:54 AM vaclav_sal via Groups.Io <vaclav_sal=
[email protected]> wrote:

This discussion answers many "who is on first" questions. Some of
them I had posted on my first post and received some answers too.
I have been reading the mail ever since that first post and have
confirmed my suspicion that this forum is users forum, not product
developers forum. (Asking other than "how do I do this..." got me labeled
as complainer. Very nice. )

I am still working on my original project, however, I have been doing some
research into replacing current processor with a device with build in
Bluetooth and WI-fi hardware for ANOTHER project.

So this idea of publishing pertinent board documentation which woudl allow
to replace the current STM32F072 got my attention.

This post is just initial fact finding.
Currently I am not interested in NanoVNA_WB , as in "WI-Fi" and
"Bluetooth" hardware as a money making enterprise, just as a proof of
concept of project.
If anybody like to "help out / participate " please reply "Private"
since this is NOT user question / post etc.

Vaclav AA7EJ

On 11/17/19 11:44 AM, Nels Nelsen wrote:

I have seen others solve this problem but they use developer tools not
available to me.

Still not able to load nanoVNA-saver on any of my Linux computers. (Ubbuntu
XFCE and Mint XFCE ) If you have nanoVNA-saver running on your Linux
computer please tell me what "desktop" version of Linux you are using ??

???? The most recent version of nanoVNA-saver runs fine on Linux Mint 19.1 Cinnamon.? Most development tools are available for everyone.

There is another way to skin the cat so to speak and measure these non resonate high (or low) Z antenna. That is to say an antenna not near 50 ohms.

Consider going through the effort of constructing a careful and well characterized "L matching" system, one where the L and C components are operable thru a HF range where the self resonate characteristics can be neglected. Then this LC matching system can be taken to the antenna under test and simply use the VNA as an accurate high dynamic range reflectometer. You can readily tweak the match system to obtain a 40 or 50 dB return loss! Then the LC match system now retains the information you desire, namely the Z of the antenna under test. If you take the network back to the shack and terminate the VNA port into 50 ohms, then the antenna port conjugate is the desired antenna Z. Now you could try to measure this Z with your VNA again, or have a calibrated L and C value already recorded on this little LC match system tool. Knowing the L and C values required to achieve the good return loss permits you to calculate the antenna Z.

Of course, you may consider a PI match or a TEE, etc... dependent on the range of expected antenna Z in lieu of the L. However, the L is attractive as it results usually in a minimum Q match solution.

Alan

Hi Oristo
My comment regarding about "waste of time" regarding S21 measurements was solely based on how to save a S21 sweep and convert it from transmission to reflection.
There are other option which I have tested to night where an ordinary SOL calibration is done ether in shunt mode or Serial mode.
The shunt mode where a T-Adaptor is inserted between the two SMA male male test cables and a SOL calibration done at the third leg of the T-Adaptor. If the T-Adaptor is FFF then use the male calibration kit and in the NanoVNA-Saver you may use either ideal or the settings I published for male kit. If you use a FMF T-adaptor allowing a female bulkhead/PCB edge adapto to be fitted where the DUT is soldered between center pin and ground, then calibrate with the female calibration kit setting in the NanoVNA-saver. I have attached screen copies of the shunt method testing a 10K resistor and it works actually when seeing the parallel R and X values in the data fields for the three marker. The reading a fluctuation due to noise but by continuous sweeping and using the NanoVNA-saver averaging function it is actually not that bad. However the Shunt method are only optimum for impedances from 0 ohm and up to some 1K ohm
For the S21 series SOL calibration I used the three pin pin adaptor seen on the picture constituting Short Open and Load (two 100 ohm 1% SMD resistor soldered to the pins) and the screen copies demonstrates clearly that measuring 10Kohm is piece of cake when studying the marker data as parallel R and X. The window for R+jX is on the other hand "terrible" only because the R+JX read out and due to the 110fF measured as the capacitance of the two pins to which the 10K resistor is soldered. Ig I had used an open standard like the adaptor with 10kOhm fitted the this shunt c would have been smaller and been the shunt C of the SMD resistor and the added fringe C due to the solder added to the end of the SMD resistors. As you see when you have control of you test setup like I have demonstrated. The it is possible up to at least 100MHz to reach accurate measurement. The traces in the Smith chart shows also for the shunt method the added delay due to the Bulkhead adaptor (as the calibration is at the SMA male reference plane). It can be tempting to use the Electrical Delay in the NanoVNA menu but due to the lag of error correction in the NanoVNA it does not work satisfactory.
Final remark:
Prior to do these two new calibration methods for the NanoVNA in conjunction with the NAnoVNA-Saver do a full SOLT calibration with the two male male test cables fitted from the NaNoVNA menu and save to C0. It is always a good idea to have these two test cables fitted. This calibration is essential for the NanoVNA-saver to build upon despite it does account for the delay of the female female adaptor both for S11 and S21 calibration but no to do anything about and that is why the Electrical delay does not work properly.
Have fun
Kind regards
Kurt



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Oristo
Sendt: 17. november 2019 21:52
Til: [email protected]
Emne: Re: [nanovna-users] Increasing measurement range (ohms) ?

Hi Kurt -

Thanks as always for your expertise and patience for explaining VNA best practices!
This second paper motivates mastering T adapter techniques, particularly for low impedances.

Thinking of finding a way to measure in S21 mode with the NanoVNA is "waste of time"
as it requires that both the Ch0 and Ch1 output/input impedance is pure 50 ohm.
In the appendix2 of one of the report S21 measurement documented.

I am using it on Linux Mint Cinnamon 19.1 NanoVNA version 0.2.0 and it
works fine.

Dave
N2VUZ

Hi Andy -

am I to understand that it's worth trying to
calibrate with a load other than 50R
then doing some simple back tracking calcs ?

The W0QE paper indicates that, seemingly because of errors introduced
by parabolic curve fitting in AIM4170 software,
calibrating with higher impedance yielded results that he liked better.
Some issues are:
* At least for the nanoVNA resistance bridge, sensitivity drops away from 50 Ohms.
Sensitivity is related to curve slope steepness here:

...so e.g. errors and noise have more impact.
Since a reflection bridge can use a reference load higher than 50 Ohms,
it might work better for higher impedances, but requires correcting and converting nanoVNA S21 values.
* Where to find / how to verify high frequency impedance calibration references?
With good high impedance calibration references, a 9:1 transformer may be characterized and used.

As Kurt pointed out, W0QE S21 result depends on ideal (or at least precisely known) CH0 and CH1 impedances.

I am using Linux Mint Tina and it works well.

Hi Kurt -

Thanks as always for your expertise and patience for explaining VNA best practices!
This second paper motivates mastering T adapter techniques, particularly for low impedances.

Thinking of finding a way to measure in S21 mode with the NanoVNA is "waste of time"
as it requires that both the Ch0 and Ch1 output/input impedance is pure 50 ohm.
In the appendix2 of one of the report S21 measurement documented.

I am looking for help to try and fix this problem,
My Linux computer complaint is :

Could not load the Qt platform plugin "xcb" in "" even though it was found.

Indications are this is a library problem with python on Linux .

I have seen others solve this problem but they use developer tools not
available to me.

Still not able to load nanoVNA-saver on any of my Linux computers. (Ubbuntu
XFCE and Mint XFCE ) If you have nanoVNA-saver running on your Linux
computer please tell me what "desktop" version of Linux you are using ?? I
am using XFCE and it does not appear to support nanoVNA-saver.

Thanks in advance,

Nels

--




n_n

If you can lay your hands on some of the old General Radio (GR) connectors,
they would work well. Finding them will be the challenge.

Dave - W?LEV

--

*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

Hi Oristo
It is a difficult task to measure highZ components based on two restrictions.
For the first the DUT used to test the VNA test set up is it really a HighZ with flat response over a large frequency range and for the second part does the test setup destroy the measurement of the well calibrated VNA due to parasitic components.
I have done several reports on the topic where I demonstrated the need to characterize the test adaptor and proven it is possible to measure a 10Kohm resistor pretty accurate. One of the obstacles is that it is forgotten that VNA read outs are as series impedance R+jX and it changed to parallel representation it suddenly is showing fat better results
I see the article you refer to has fought these aspects and not found the clue as the VNA used are probably able to do better but the testjig is "killing" the results.
For a test with the NanoVNA the best way is to use a SMA PCB Edge/bulbhead adaptor and solder the component to centerpin and ground with minimal solder (fringe C) and no leads added. The calibration must be with female kit setting in the NanoVNA-Saver and read out as parallel R and Parallel X. There is one more "snake" as the measurement plane is not the calibration plane for the male SMA to which the female test adaptor is fitted but the QRP firmware has added the feature of positive delay shift so that calibration plane is moved to the rear of the bulkhead/PCB edge adaptor and thus elimination the shunt C and series inductance og said adaptor.
Thinking of finding a way to measure in S21 mode with the NanoVNA is "waste of time" as it requires that both the Ch0 and Ch1 output/input impedance is pure 50 ohm. In the appendix2 of one of the report S21 measurement documented.
to calibrate and measure a DUT like a toroid in shunt mode_2.pdf
Http://www.hamcom.dk/VNWA/How to calibrate and measure a DUT like a toroid correctly the smart way.pdf
Copy paste the URL and watch out it is tough reading so just skim it
Kind regards
Kurt



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Oristo
Sendt: 17. november 2019 15:40
Til: [email protected]
Emne: Re: [nanovna-users] Increasing measurement range (ohms) ?

I wonder how others tackle the problem ?

This discussion answers many "who is on first" questions. Some of
them I had posted on my first post and received some answers too.
I have been reading the mail ever since that first post and have confirmed my suspicion that this forum is users forum, not product developers forum. (Asking other than "how do I do this..." got me labeled as complainer. Very nice. )

I am still working on my original project, however, I have been doing some research into replacing current processor with a device with build in Bluetooth and WI-fi hardware for ANOTHER project.

So this idea of publishing pertinent board documentation which woudl allow to replace the current STM32F072 got my attention.

This post is just initial fact finding.
Currently I am not interested in NanoVNA_WB , as in "WI-Fi" and "Bluetooth" hardware as a money making enterprise, just as a proof of concept of project.
If anybody like to "help out / participate " please reply "Private" since this is NOT user question / post etc.

Vaclav AA7EJ

no, it doesn't work because it requires Android 7+

--
*73, Lucio I0LYL Rome, Italy*