NanoVNA Custom Software

[joeqsmith]

Because AppCAD and METAS are so limited, I started to look for another program to perform some sort of sanity check.   This program is JAVA based and may be helpful.   

https://personal.utdallas.edu/~frensley/

I have included the touchstone file created with the V2Plus4 that was used to generate the attached plots.   At least my math appears to be correct for the stability coefficients, or at least matches up with what they show.    A good sign.   

Notice that they have some support for gain as well which is something I may add.   They do not support the stability circles.   Maybe there are other free tools that could be used to verify this part.   

In fact, most modern VNAs have this stability analysis option built-in.

The old Agilent PNA I bought doesn't have any features like this.  They don't even include TDR with the base install.  Maybe someone with a new VNA can load the file and show some screen shots. 

[joeqsmith]

CMTs software does not appear to have support for it.

[joeqsmith]

After much hair pulling, the power calculation is sorted or at least matches with the Texan's software.

[Alextsu]

Because AppCAD and METAS are so limited, I started to look for another program to perform some sort of sanity check.   This program is JAVA based and may be helpful.   

https://personal.utdallas.edu/~frensley/

I have included the touchstone file created with the V2Plus4 that was used to generate the attached plots.   At least my math appears to be correct for the stability coefficients, or at least matches up with what they show.    A good sign.   

Notice that they have some support for gain as well which is something I may add.   They do not support the stability circles.   Maybe there are other free tools that could be used to verify this part.   

Thank You very much for the links, Joe.
This seems to be a very helpful tool, I shall give it a try when I have some more spare time.
The Available gain graphs are also very interesting feature, thanks!
You are correct, I don't have all the necessary setup to perform the SW tests right now.
I ve got several SpDT SMA coax switches from Anritsu that I plan to adopt in tests.
Besides, I do have a low-cost VNA at hand that supports extracting full 2-port set of S-parameters from the DUT.
Thanks,
Alex

[joeqsmith]

Thank You very much for the links, Joe.
This seems to be a very helpful tool, I shall give it a try when I have some more spare time.
The Available gain graphs are also very interesting feature, thanks!
You are correct, I don't have all the necessary setup to perform the SW tests right now.
I ve got several SpDT SMA coax switches from Anritsu that I plan to adopt in tests.
Besides, I do have a low-cost VNA at hand that supports extracting full 2-port set of S-parameters from the DUT.
Thanks,
Alex

Assuming your VNA supports Touchstone, maybe you can use it for your amplifier designs.   I had long ago removed JAVA and had to install it just for this app.  If you are aware of any better Touchstone post processors that can do some of the things you want, just provide a link. 

In fact, most modern VNAs have this stability analysis option built-in.

I looked at Keysight and did not see where they had anything like stability circles included in their software.  If CopperMountainTech and Keysight don't support it, I am wondering which models do?   

The problem I see with using two discrete  DPDT coaxial switches is you are placing unterminated stubs on the transmission lines.   Maybe it won't matter for what you are doing. 

Which low cost VNA are you using that has support for 2-ports?   Depending on the specs, it may be worth porting the software to it.   

[joeqsmith]

While searching for tools to validate my math,  I ended up watching a very basic video showing all the details for the stability circles.   Attached is the output from my math which if you watch the video, seems to match up.   

[joeqsmith]

Time to start working on the documentation.    Attached showing the stability menu.  Poor amplifier.

[joeqsmith]

After some thought, the plan is to add onto the 2-Port Plot tab.

What's might be interesting to see in the SW features is the ability to plot a family of load stability circles on one graph simultaneously in case of broadband stability analysis, for implemented frequency sweep, as it is shown in the last section of L. Besser paper
Thanks,
Alex

Plotting a family of circles is easily done in a text book, but I'm not sure how it would be accomplished in the real world.   These are data formatting questions that I had hoped you would clear up by showing how your tools work.    Considering there is a circle for each point collected.  Even the original NanoVNA will capture 101 data points, so 101 circles.   OWO mentions the V3 supporting 10,000 data points. 

Calculating 10,000 data sets shouldn't pose much of a problem but plotting them may be a bit much.   

One way to avoid the mess would be to concatenate all the circles into one array and plot that as a single graph.  Of course that would be a fairly large array but Labview can handle that much easier than trying to graph several discrete circles. 

[Alextsu]

One way to avoid the mess would be to concatenate all the circles into one array and plot that as a single graph.  Of course that would be a fairly large array but Labview can handle that much easier than trying to graph several discrete circles.

That's very nice, would be great,
Thank You !
Concerning the stability graphs in the VNAs, as far as I know, Rohde Schwartz analyzers have them as an option (but only K, mu1 & mu2 plots).
I've believe that Keysigh have this option for VNA, too, as far as I have seen it's description in Joel,'s textbook.

Which low cost VNA are you using that has support for 2-ports?   Depending on the specs, it may be worth porting the software to it.   

I have Jan's open source VNA, it's a fairly new project,
 the USB protocol they had implemented is still a subject to minor changes as the SW is still under development.
As we had discussed previously, this work is still in progress, and it is not properly documented yet.

[joeqsmith]

Which low cost VNA are you using that has support for 2-ports?   Depending on the specs, it may be worth porting the software to it.   
[/quote]
I have Jan's open source VNA, it's a fairly new project,
 the USB protocol they had implemented is still a subject to minor changes as the SW is still under development.
As we had discussed previously, this work is still in progress, and it is not properly documented yet.
[/quote]


I tried downloading their latest software and loaded in that last Touchstone file.  I don't see how you plot the stability with it.  It seems very limited for such an expensive device.    Are you using a different program with it?

[Alextsu]

I looked at Keysight and did not see where they had anything like stability circles included in their software.  If CopperMountainTech and Keysight don't support it, I am wondering which models do?   

I have double checked Joel's textbook and it appears that formerly Agilent VNA's SW had a built-in equation editor, which made it possible to plot the stability factor plots on the screen.
The user just had to enter the necessary maths equation with S-parameters there.
But the book also states that more recent analyzers already have this plots for K, delta and mu factors available, together with the test=Pass or Fail criterion.
All other calculations could be done as post-processing in external SW, I assume something like Matlab, after the S-parameters export in Touchstone format.

Jan's VNA also has this Touchstone format S-parameters export feature and some kind of built-in equation editor, too.
So, in theory,  it's possible to do the job. But in practice it might be limited to different measurements errors.

[joeqsmith]

I looked at Keysight and did not see where they had anything like stability circles included in their software.  If CopperMountainTech and Keysight don't support it, I am wondering which models do?   

I have double checked Joel's textbook and it appears that formerly Agilent VNA's SW had a built-in equation editor, which made it possible to plot the stability factor plots on the screen.
The user just had to enter the necessary maths equation with S-parameters there.
But the book also states that more recent analyzers already have this plots for K, delta and mu factors available, together with the test=Pass or Fail criterion.
All other calculations could be done as post-processing in external SW, I assume something like Matlab, after the S-parameters export in Touchstone format.

Jan's VNA also has this Touchstone format S-parameters export feature and some kind of built-in equation editor, too.
So, in theory,  it's possible to do the job. But in practice it might be limited to different measurements errors.

I was thinking that

In fact, most modern VNAs have this stability analysis option built-in.

did not mean you would have to buy Matlab or use the built in equation editor to process the data.   Rather I am expecting a single button or menu option that plots the family of stability circles along with all the factors you are asking about.   I've spent a few hours putting the code together and would expect anything I show would be a pale compared with the what the larger companies like Copper Mountain Tech and Keysight offer.  Oddly enough, I am not finding these features.

What would be interesting is to use the internal equation editor to plot the family of stability circles you asked about, even with a small data set.  Some of my old equipment supports a way to write custom code that runs native to the instruments.  I've never had a use for it as the desktop PCs will normally have far more capability.   With Jan's VNA running headless, you're already running on the PC.    This is where changing to a new version of LabView could improve things. 

[joeqsmith]

Concerning the stability graphs in the VNAs, as far as I know, Rohde Schwartz analyzers have them as an option (but only K, mu1 & mu2 plots).

I had a look at RS and also could not find anything showing stability circles. 

https://cdn.rohde-schwarz.com/pws/dl_downloads/dl_application/application_notes/1ez65/1EZ65.pdf

Searching on Google images, I couldn't locate a single screen shot of ANY vendor showing this feature.    I suspect that doing a family of them like I show would be too CPU intensive.  Or maybe they don't get a lot of requests for it from their customers.     Too bad Brian and Joel from Copper Mountain Tech and Keysight don't chime in.  They may be able to provide some much needed background on it.   


Shown using the typical stability circles.  I have not rolled it into my software yet.   

[Alextsu]

Concerning the stability graphs in the VNAs, as far as I know, Rohde Schwartz analyzers have them as an option (but only K, mu1 & mu2 plots).

I had a look at RS and also could not find anything showing stability circles. 

https://cdn.rohde-schwarz.com/pws/dl_downloads/dl_application/application_notes/1ez65/1EZ65.pdf

Searching on Google images, I couldn't locate a single screen shot of ANY vendor showing this feature.    I suspect that doing a family of them like I show would be too CPU intensive.  Or maybe they don't get a lot of requests for it from their customers.     Too bad Brian and Joel from Copper Mountain Tech and Keysight don't chime in.  They may be able to provide some much needed background on it.   


Shown using the typical stability circles.  I have not rolled it into my software yet.   

Yes, You're correct, the "stability circles" is a feature that is still unavailable in VNAs.
I just wanted to point out that "stability factors" plots are already available in most modern VNAs.
This caused some misunderstanding, I guess.
Sorry about that

[joeqsmith]

Yes, You're correct, the stability circles is a feature that is still unavailable in VNAs.
It is partly explained by the fact that mu1 & mu2 are considered enough for checking DUT amp behaviour.
Also, Your should not expect much from the CopperMountain as far as at is just a spin-off from a Russian Planar company.

I assume you had a reason for wanting to see the stability circles plotted.  Were you asking just to see if I was able to plot them using LabView?  If so, hopefully I have answered that question for you. 

If I had the disposable cash, I would have ended up with a CopperMountain product.  Specifically, the one Brian used to measure that common mode coaxial transformer for us.

I watched this series from Keysight on stability.  Part 1 mentions some of other factors used. 
 

[UR5FFR]

Hi,

I want to present my development for impedance measurement and matching network design. Software working with S-A-A V2, NanoVNA V2 and NanoVNA-F V2. Its easy to use and freeware. Include user manual in PDF format.

A short video demonstrating the main features of the program.



You can download software here

[joeqsmith]

Demonstration of the stability circles after Alextsu's request.   
 

[joeqsmith]

Both programs for the original and V2+4, along with the manual have been uploaded to Github.   The older software has been removed.

[m3vuv]

just wondered if there are any versions of the nano vna that cover 2.4ghz wifi?

[joeqsmith]

just wondered if there are any versions of the nano vna that cover 2.4ghz wifi?

https://nanorfe.com/nanovna-v2.html

I had made a review for the V2+4
https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3427308/#msg3427308


Here are a few other low cost VNAs:

https://github.com/jankae/LibreVNA
https://www.arinst.net/
http://www.mtinst.com/wiki/index.php/VNA6000C

[m3vuv]

so is that a yes or no?,my nanovna is the one that had a 2.8 inch screen but i swapped the screen for a 3 inch screen from aliexpess,just wondered if firmware will make it work for 2.4 ghz,im sure it goes to 300mhz and 900 using harmonics.

[joeqsmith]

so is that a yes or no?,my nanovna is the one that had a 2.8 inch screen but i swapped the screen for a 3 inch screen from aliexpess,just wondered if firmware will make it work for 2.4 ghz,im sure it goes to 300mhz and 900 using harmonics.

It depends what you are asking.  From your original question, "just wondered if there are any versions of the nano vna that cover 2.4ghz wifi?", there are at least two models of the NanoVNA that have an upper frequency beyond 2.4GHz.   So YES to question 1. I provided a link to them.    I suspect now what you really want to know is if firmware is available that will allow the original NanoVNA to work past 2.4GHz.   That, I don't know, but, if there was I can't see it being of any use.  The performance is poor once you move past 300MHz.   Still, if all you care about is the frequency, then maybe.

**
I recently posted some data for the original NanoVNA, H4, V2P and V2P4.   You can get some idea about the noise and dynamic range.  Both the H4 and my original NanoVNA have firmware that support up to 1.5GHz.   Doubling that, is certainly going to make matters much worse.   Maybe you only need 1dB of dynamic range.
https://nanorfe.com/forum/VNA-output-level.html   

[Alextsu]

Hello, Joe,
Thanks for adding all the new features, looks great! Very nice!
Though I had not tried them yet, but I have a question:
May be it's possible to add an "S2P load" button to UI?
I was thinking of possibility to use the new SW features to work directly with imported .S2P Touchstone files,
is it possible?
Also, when I try to Save or Load any S1P files in Your app, they all are stored or read only with a comma "," in the decimal point format, while all other Touchstone use dot "." decimal point separator.
Is this by default or due to some regional LabView settings I have to tune?
Any suggestions about that?
Thank You!

[joeqsmith]

Hello, Joe,
Thanks for adding all the new features, looks great! Very nice!
Though I had not tried them yet, but I have a question:
May be it's possible to add an "S2P load" button to UI?
I was thinking of possibility to use the new SW features to work directly with imported .S2P Touchstone files,
is it possible?
Also, when I try to Save or Load any S1P files in Your app, they all are stored or read only with a comma "," in the decimal point format, while all other Touchstone use dot "." decimal point separator.
Is this by default or due to some regional LabView settings I have to tune?
Any suggestions about that?
Thank You!

I could read the S2P files as well and have thought about dropping S1P all together.   I also thought about writing a complete viewer.  For now, I still use AppCAD and METAS.  Both are free.  Both have their limitations.   Another option is to use the software that came with your VNA. 

Keep in mind, that the viewer that is built into my software is currently VERY limited.  I just don't have much of a need and would rather use a third party tool if at all possible.   

There could very well be a regional problem with one or both applications.   The V2+ uses binary and so talking with the device was never a problem.  The original NanoVNA used ASCII.  I added an autotest for the regional settings but it is only for the original NanoVNA.   I have not considered the Touchstone files but I would not be at all surprised that they are also effected by the regional settings.   There is a section in the manual on how to change these settings in the INI file.  You could try that and report back if it solves your problem.   If so, I may be able to correct that in software as well.   

[joeqsmith]

Looking at my software, the regional settings would effect the Touchstone files for all of my programs.  I can certainly change my software to display the comma like you're used to but write text files with the decimal.       

I would have thought that countries using the comma separator would want that across the board.  But it sounds like in some cases you want the comma and others you don't.  I don't see in the standard where they specifically mandate the separator.   

Before I make any changes, I would be interested in hearing from those of you living in these areas if you want the Touchstone to reflect your regional settings, always use the decimal, or keep it as is and use the INI file?   It's quick change for me, so no big deal but let's make sure that it's the right solution.