Electronics > RF, Microwave, Ham Radio

NanoVNA Custom Software

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joeqsmith:
I show the VNA without calibration for a reason.  No doubt that reducing the noise in general is a good thing as long as there is no loss of information. 

Because I don't tune a lot of filters, I'm not sure what people would generally consider an acceptable update rate.  I would imagine instant feedback is desired but maybe once every few seconds is good enough for a few.   Personally, I couldn't use something that slow to make several adjustments.  Giving up data points for faster feedback is certainly something users would consider when trying to use it to tune a filter.         


--- Quote ---PS sweep speed after 6.3G decreased, need more wait generator ready.
--- End quote ---
Also, the SNR improves as we move below that.  Its less of a problem.   

As I mentioned, the one person who wrote was planning to average to increase the dynamic range.  The one thing they never mention is what they required.    It was a communications application so I would assume that they would need something better.


I was thinking I could take a filter and run it on the Lite using the firmware calibration (what ever parameters/procedure you recommend) and store the Touchstone data to the SD card.  Then run it with my software.  Repeat it with the V2Plus4 and maybe my old VNAs.   So I pull out a SD card go to slide it into the slot and it disappears into the unit.  :-DD   I remove the 4 screws to recover my card and then make sure I fits.  No problem.  I then put the case back together and try to insert the card but discover the card is too short and I need to use something to push it in deeper than the case allows to get it to lock.   :-DD  The experiment was doomed before it got started. 
 

joeqsmith:
You can get the card to lock with the stylist.   I attempted to use a 64G SD card but was presented with a write error.  Lucky for me, the 121GW DMM  Dave offers uses a small card which worked fine.     

We can try to look at the difference of the dynamic range of the Lite using the firmware's calibration.  Anyone could repeat that test compared with some filter I have laying around.   

joeqsmith:
Same procedure, 401 data points, 1.5G to 3GHz range.   I was going to try with the average set to 80 but was starting to fall asleep waiting for the thru.   :-DD  So I set the average to 10.  Because we were saving the data to the SD card, I ran the Lite off battery to give it the best chance possible.

Shown comparing the above setup (red) with the my software running the Lite the way I would normally use it (dark brown).   We gain about 10dB but it does slow things down.   

Also shown is the V2Plus4(tan) connected to the PC, no average and running off the PCs power.  Sadly, I know using the external power degrades the performance. 

Also shown is data another member had taken for the Jankae LibreVNA (black).   

Feel free to repeat this little experiment and see if your results show any major improvements.

joeqsmith:
I changed to 80X average and repeated the calibration and measurement.  No other changes were made.   Data was normalized to the original, non averaged data set.  There appears to be some gains at 80 but it takes a very long time to run through it.

joeqsmith:
I ran the V2Plus4 (brown) from it's internal battery and used the software to average 10X for calibration and collection.  I then compared this with the Lite (black) with the firmware 80X average for calibration and collection (also running from battery).   




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