NanoVNA Custom Software

[joeqsmith]

I located the original articles I mentioned that talk about using the S-parameters with SPICE.   

[joeqsmith]

The first attached graph shows S21 while sweeping the collector current .   A bit odd as the gain dips sharply when the current is very low.   There is no amplification until roughly sweep 112. 

The second graph is the same setup but driving the DUT a bit harder and zooming in.  The datasheet shows the 1dB compression at 100MHz is roughly 17.5dB.   You can clearly see it has started to compress at 19.

[erikka]

If I make no mistake interpreting the nanoVNA schematic and the datasheets of the SA612 and the ADC you have to stay below about -10dBm for P2.
The SA612 amplifies about 17dB (below 500MHz). The max input level to the ADC is about 0dBm and the resistor network at P2 reduces the level with about 6dB. Or am I making a mistake?

[joeqsmith]

If I make no mistake interpreting the nanoVNA schematic and the datasheets of the SA612 and the ADC you have to stay below about -10dBm for P2.
The SA612 amplifies about 17dB (below 500MHz). The max input level to the ADC is about 0dBm and the resistor network at P2 reduces the level with about 6dB. Or am I making a mistake?

https://www.eevblog.com/forum/rf-microwave/nanovna-custom-software/msg2598729/#msg2598729

[erikka]

I was not aware the output spec is the same as the input spec. Please ignore my post 

[joeqsmith]

I was not aware the output spec is the same as the input spec. Please ignore my post 

... I didn't see in the Nano's manual where they talk about at what point it starts to go nonlinear.   I doubt people care about it. 
...
Hard to say how the different flavors of Nanos behave or what would be a safe region to use.   

It should be safe to say it supports a thru without distortion or what would be the point of running a SOLT.   From playing with that transistor, we can get some idea but I haven't looked into it any further.  Staying below the output level should be safe but the dynamic range of the Nano is pretty limited.  My low cost transfer relay certainly doesn't help with this.   

[joeqsmith]

Plot showing all four S parameters.    This data was collected automatically using the low cost transfer relay, after running a full 2-port calibration.   The T-check was installed as the load. 

[joeqsmith]

1000 mating cycles, I like that.

https://youtu.be/U3Fabnw9U04?t=40

[battlecoder]

I just started following this thread since I'm interested in getting a nanoVNA, and you've done such an impressive work. Thanks for sharing all the research and tests you've done on this device!

[joeqsmith]

I just started following this thread since I'm interested in getting a nanoVNA, and you've done such an impressive work. Thanks for sharing all the research and tests you've done on this device!

No problem.  Glad you are finding them of interest. 

In the attached plot, the Nano is used to monitor the effects of applying corona dope to a 5 pole low-pass filter and watching it dry.

The filter was attached to the transfer relay after cal, then used as a baseline.  The plot is the deviation from that baseline. 

The first few sweeps (towards the back), it is reasonably flat with a clean PCB.  The deep blue is after applying the liquid dope.    As it slowly drys, I would expect it to return to normal once fully cured.   

[z33t]

Hello,
Can You tell me what "CORRECTION" does to NanoVNA, plase?
It seems that it is something like 10 dB attenuator, but I am not sure.

"CORRECTION" is in "CAL" menu.
Thanks

[joeqsmith]

Hello,
Can You tell me what "CORRECTION" does to NanoVNA, plase?
It seems that it is something like 10 dB attenuator, but I am not sure.

"CORRECTION" is in "CAL" menu.
Thanks

It's just an easy way to enable / disable the correction factors created after the unit was calibrated.   

[z33t]

Thanks

[z33t]

I have made comparison between Rohde Schwarz and NanoVNA.
The same homemade VHF Helical Band-Pass filter was measured with both instruments.
The results was amazing!
Here is the pictures:

[joeqsmith]

Looking good. 

[joeqsmith]

Someone had asked me about making one more video for the Nano.   As I said in the attached, I am not apposed to it if there is some interest.   Feel free to chime in if there is something else you would like to see.   

[Roland_W]

Dear All,

It look like a issue with the calibration procedure, or the calibration method is "simple".
I found some description about VNA project, with the issue of the simple method. http://hforsten.com/improved-homemade-vna.html

It could be some track for improve the software in this device.
Best regards
Roland

[NY2KW]

Instead of GaAs pin diodes you could use this:  https://www.psemi.com/pdf/datasheets/pe4250ds.pdf which supposedly has better performance up to 3 Ghz

Jerry NY2KW

[Evi]

The topic should have been called Private Software.

[joeqsmith]

Instead of GaAs pin diodes you could use this:  https://www.psemi.com/pdf/datasheets/pe4250ds.pdf which supposedly has better performance up to 3 Ghz

Jerry NY2KW

I don't see how that would ever work.   You would need to sketch out how you would use them as I am lost.

[joeqsmith]

The topic should have been called Private Software.

As my software continues to evolve, I start thinking maybe it's something that could be useful for others,  but then comments like yours bring me back to reality.  So thanks for that wake up call.

SP

[5q5r]

Inspired by Joe's great YouTube videos on the NanoVNA, I went ahead and botched together a little Python app that does some of the same things (most importantly, multiple sweeps to increase the amount of data points.)

It's open source and on github, as "NanoVNA-Saver" (because I initially just made it to save s1p/s2p files). I daren't post a link in my first post on this forum though :-)

Thanks Joe for the inspiration, and I hope some of the rest of you may find it useful.

[joeqsmith]

Inspired by Joe's great YouTube videos on the NanoVNA, I went ahead and botched together a little Python app that does some of the same things (most importantly, multiple sweeps to increase the amount of data points.)

It's open source and on github, as "NanoVNA-Saver" (because I initially just made it to save s1p/s2p files). I daren't post a link in my first post on this forum though :-)

Thanks Joe for the inspiration, and I hope some of the rest of you may find it useful.

Welcome to the forum.

I just released a viewer Q&A video for the Nano that you may be interested in as well.   

[N2CUA]

The topic should have been called Private Software.

As my software continues to evolve, I start thinking maybe it's something that could be useful for others,  but then comments like yours bring me back to reality.  So thanks for that wake up call.

SP

Thats sad .. One guy ruined it for the rest of us    
I truly appreciate your hard work and attention to detail ..
You have a lot of awesome videos .   ( is it working? lol )
You truly do though ..

Would love to play with that software ..
Can I trade you for a few mini-circuits SMA style attenuators?

I used to program .. but it was awhile ago ..  retired USAF TSgt ..
So have some extra time to play and try to keep my mind active ..

Just bought the NanoVNA .. and still learning ..
Ham radio operator - N2CUA

Either way .. thanks so much for all your great info ..

[joeqsmith]

The topic should have been called Private Software.

As my software continues to evolve, I start thinking maybe it's something that could be useful for others,  but then comments like yours bring me back to reality.  So thanks for that wake up call.

SP

Thats sad .. One guy ruined it for the rest of us    
I truly appreciate your hard work and attention to detail ..
You have a lot of awesome videos .   ( is it working? lol )
You truly do though ..

Would love to play with that software ..
Can I trade you for a few mini-circuits SMA style attenuators?

I used to program .. but it was awhile ago ..  retired USAF TSgt ..
So have some extra time to play and try to keep my mind active ..

Just bought the NanoVNA .. and still learning ..
Ham radio operator - N2CUA

Either way .. thanks so much for all your great info ..

Thank you for your service to our country. 

I'm glad you enjoyed the videos and thread.  This was put together for a friend of mine who wanted to learn a little more about VNAs and I decided to try and help them along.   Their use of the VNA is more for PCB design.  Personally, electronics has been one of my hobbies for many years.  I have been in a continual state of learning but still know hardly anything about it.   

I've never understood where certain people came up with the idea that I owe them.   It's not what I would expect from a technical community and I'm sure it's obvious that my threshold is fairly low when dealing with them.