NanoVNA Custom Software

[joeqsmith]

Flipper's second Lite arrived.   Sadly, same problem as his original.   Sounds like the supplied USB cable was also bad.   Measuring the voltage at the (HP Z640) USB connector at 5.098V.   There is also a rapid charge port which outputs 5.25V.  Both are too high for the LiteVNA to work properly but note that there is a difference. 

Looks like the diode dropped powered hub is the fix for now.  Flipper is sending me the VNA and I will attempt to make the Changes Dislord mentioned and see if we can improve the low frequency performance.

[realfran]

LiteVNA64: Remove D1 R7 R1 -Please disconnect the battery and USB power connection when modifying the circuit. The battery must be connected after the modification is completed to work properly.
This is the modification suggested.
Another suggestion is: Calibrate without a USB cable (the reason is on calibration is embedded in the noise).
I calibrate the LiteVNA on battery with USB cable disconnected I started the NanoVNA-Solver V2.8 and I get this.

[joeqsmith]

I was referring to the front end modifications Dislord had mentioned:

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg4015222/#msg4015222

In Lite if remove DC block capacitor and ESD protection diode possible get better results on low frequency range < 10M (but this huge increase chance burn rf switch)

I have no plans to modify the power supply section.   I had asked a few questions to try and understand if these changes would cause other problems but we did not get a response.   So for now, Flipper will stay with the low voltage powered hub.   

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg4030855/#msg4030855

***

Another suggestion is: Calibrate without a USB cable (the reason is on calibration is embedded in the noise).
I calibrate the LiteVNA on battery with USB cable disconnected I started the NanoVNA-Solver V2.8 and I get this.

The data I've presented in regards to the power supply noise has all been without calibration.  Calibration isn't a panacea able to overcome such hardware problems.   

That said,  we always run them with a PC.  We expect raw data from the VNA and calibration is handled by the PC.  It should be easy enough to replicate. 

***
Snip a USB cable and expose the power leads.  Power the VNA from an external supply.   Flipper's will start to act up with 5.04V applied.  I don't know the upper voltage limit before damage but it was plugged into that charge port.  Keep it below 5.2V and I suspect you are fine.   
Assuming no calibration, I would expect you to measure 50-60dB in the 400kHz to 1MHz range. 

Then you can try to calibrate your way out of it.  Let me know how it works out for you. 

[realfran]

On the PC software, I don't perform any calibration of their raw data from the VNA

[joeqsmith]

On the PC software, I don't perform any calibration of their raw data from the VNA

I understood that from the photo and what you had wrote.

Another suggestion is: Calibrate without a USB cable (the reason is on calibration is embedded in the noise).
I calibrate the LiteVNA on battery with USB cable disconnected I started the NanoVNA-Solver V2.8 and I get this.

However, you made the suggestion which suggests to me that you do not understand some of the basics.   

Run through a calibration on battery (stand alone, no PC), but do not insert any of the standards when doing it.  Create a bad calibration.  Save it to 0.     Reset the unit and it should show a lot of random garbage.  Now connect it to the PC and run Solver.   If you see the same random garbage, then something is wrong!!   Again: 

We expect raw data from the VNA and calibration is handled by the PC.

I had discussed this with Dislord a few pages back.  There was a time where he would not send the raw data but this was corrected: 
https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3947854/#msg3947854

The data that you show is what I expect.   

[realfran]

ok, thank you for the explication, so the power supply on the LiteVNA modification is not important to reduce the noise after 400Khz.

[joeqsmith]

ok, thank you for the explication, so the power supply on the LiteVNA modification is not important to reduce the noise after 400Khz.

Solving the noise Flipper was seeing is very important!  I'm not sure why you would think otherwise.   The modifications you posted are not understood and we chose to solve it a different way to avoid potential problems. 

Did you run the cal as I suggested and prove it to yourself?
Did you run the VNA off an external supply as I suggested, to force the condition and then try to improve it with calibration? 

[jspencerg]

Re: Getting started with hardware.  Versions and connection success.
1. Versions
"THIS IS NOT THE LATEST RELEASE AND ONLY SUPPORTS THE V2 PLUS. IT SHOULD BE INSTALLED FIRST!"
I've installed and am running the program. Indicates it is Rev 0.10.
Where is Rev 2.05 & 2.07 as shown in manual?

2. Connection state looking good.
Windows Device manager sees the nanos' connections.  As stated in manual, this install(0.10) links with the v2plus4 but not the original nano. I look forward to comparing results from the two.

[joeqsmith]

Re: Getting started with hardware.  Versions and connection success.
1. Versions
"THIS IS NOT THE LATEST RELEASE AND ONLY SUPPORTS THE V2 PLUS. IT SHOULD BE INSTALLED FIRST!"
I've installed and am running the program. Indicates it is Rev 0.10.
Where is Rev 2.05 & 2.07 as shown in manual?

2. Connection state looking good.
Windows Device manager sees the nanos' connections.  As stated in manual, this install(0.10) links with the v2plus4 but not the original nano. I look forward to comparing results from the two.

Make sure you select the correct branch.   
https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg4021102/#msg4021102


Also

The few people who follow my channel also may have seen the following where I talk about how to install it.
https://youtu.be/scZ3kZ4Q2sQ?t=1045

[jspencerg]

Re: branch choice on install
I never saw a place to make a choice.  Was this a file selection or installer option?

[joeqsmith]

Re: branch choice on install
I never saw a place to make a choice.  Was this a file selection or installer option?

Press the Main button to show the available branches.

[joeqsmith]

Once you select the correct branch, you need to select the ZIP file

[joeqsmith]

After selecting the ZIP file, you must download it to your PC.    It will need to be decompressed before it will run. 

[joeqsmith]

To save the file to your PC, you will need to select save and then press the OK button.

[joeqsmith]

You will need to decompress the file.  I use 7-zip.   

[joeqsmith]

I suggest you also read the following post:

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg4021714/#msg4021714

If you are still having problems, provide details and maybe I can walk you through it.   

If you do manage to figure out how to get it running, I am not sure you will get the results you are looking for.  The impedance you are targeting could very well be far below what the NanoVNA can measure.  You will also have to remove the ground loop between the two ports and you will need a way to block the DC.  If you get all of that sorted out, the next problem will be not damaging the VNA when making the measurements!       You should be able to get down below 10mOhms.  20kHz or so is doable. 

Out side of Flipper and myself, I am not aware of anyone else attempting to make these measurements (with the NanoVNA).   Let me know how it works out.

[realfran]

The modification is suggested by Hugen "

Since LiteVNA is designed to work without a battery installed, it switches to using USB power directly when connected to USB power. When working with the USB power supply, the voltage of the input DC-DC boost power supply is very close to the voltage of the output, resulting in a very narrow PWM pulse bandwidth of the switching power supply, and these pulses may enter the IF, resulting in large measurement noise.
To avoid this interference, the power supply circuit can be modified so that the input to the switching power supply always comes from LiteVNA64 circuits are slightly different, with the following modifications.

LiteVNA64: Remove D1 R7 R1
Please disconnect the battery and USB power connection when modifying the circuit. The battery must be connected after the modification is completed to work properly.

"For me is impossible to make this modification for my sight and some shaking hand"

[jspencerg]

Re: Finding installation files
Thanks for the details.  GitHub is not intuitive.  Installs went fine. Linking successful for both nanoVNA's.
My computer has a 1920x1080 pixel screen.  Your program interface has lots of details. Could you enable a larger(stretchable?) VI window?
Thank you!

[joeqsmith]

Re: Finding installation files
Thanks for the details.  GitHub is not intuitive.  Installs went fine. Linking successful for both nanoVNA's.
My computer has a 1920x1080 pixel screen.  Your program interface has lots of details. Could you enable a larger(stretchable?) VI window?
Thank you!

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3986420/#msg3986420

[joeqsmith]

My software was released to the public over a year ago.  Most of the basic questions have been asked and answered a few times over.     In the upper right corner, there is a search button.   You can type in what you want to search and the select the search button.   

[jspencerg]

Re: VI screen size
I followed link supplied and then followed those links. Reading your replies leads me to think you are aware of the screen real estate issues,  like program's current behavior and do not intend to modify the interface options.  Correct?
I tried all permutations in the compatibility properties as suggested by ALW on 210805 in this thread. One option made window smaller, but nothing increased the window size.

[jspencerg]

Re: Adjusting VI window size
I found two references to controlling VI window size programmatically. Perhaps one method will work?
https://lavag.org/topic/8691-how-to-scale-ui-for-different-monitors/

https://labviewwiki.org/wiki/VI_class/Front_Panel_Window.Minimum_Size_property

[joeqsmith]

Re: VI screen size
I followed link supplied and then followed those links. Reading your replies leads me to think you are aware of the screen real estate issues,  like program's current behavior and do not intend to modify the interface options.  Correct?
I tried all permutations in the compatibility properties as suggested by ALW on 210805 in this thread. One option made window smaller, but nothing increased the window size.

From:
https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg3813893/#msg3813893

I have no plans to change this.

I didn't realize this was ambiguous statement.  You are correct.   

While I hadn't planned on a PC 101 course,  another options to change the Windows resolution is to right click on the screen and select "display settings".   Press "Identify" then select the monitor you want to change the resolution.  You need to select the box with the number.   Scroll down and select the "Display resolution".  It's a pulldown menu and you will need to press the button.   Change it to 1280 x 720.   

[jspencerg]

Re: 1280x720
LCD screens lose sharpness when displayed at something other than their optimum resolution. I thought the links I found would suggest a solution for different screen sizes. Window size does seem to be a recurring issue for users.
Thanks for your efforts.

[joeqsmith]

Re: Adjusting VI window size
I found two references to controlling VI window size programmatically. Perhaps one method will work?
https://lavag.org/topic/8691-how-to-scale-ui-for-different-monitors/

https://labviewwiki.org/wiki/VI_class/Front_Panel_Window.Minimum_Size_property

Re: 1280x720
LCD screens lose sharpness when displayed at something other than their optimum resolution. I thought the links I found would suggest a solution for different screen sizes. Window size does seem to be a recurring issue for users.
Thanks for your efforts.

Indeed.  There's a reason they have a recommended setting and why I buy hardware that suits my needs.     

Quick background.   I was reacquainted with LabView 3 and started using it when 4 was released.  I bought it for my own personal use when 5 was released.  I'm by no means any sort of expert but I'm familiar with it enough to be able to have a discussion.   

I'm certainly open to your ideas about how to improve my software.   NI offers LabView free of charge but I expect you already have it.    I suggest we start with you coding up how you envision my software should work.  Use what version of LabView you are comfortable with.   Then we can go over it.   I've already mentioned some of the problems but I suspect you have ideas on how to solve them.