Author Topic: NanoVNA Custom Software  (Read 527000 times)

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Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1400 on: December 20, 2021, 11:10:22 pm »
The LiteVNA arrived.   

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1401 on: December 21, 2021, 12:47:49 am »
The claim 50kHz to 6.3GHz.   My software doesn't care so I set it to 6.6GHz.  Looks like 6.47GHz is the upper end.    Setting it to 6.4GHz, it seems fairly accurate.  The counter is GPS referenced. 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1402 on: December 21, 2021, 01:07:28 am »
 I was really interested in seeing how low it would run.    My friend Flipper and I had ran some simple remote tests with this exact unit a few days ago and I suspected there may have been a firmware problem when running at the lower end.  Now that I have the unit, I can see it was a timeout in my software that needed to be increased to handle the slower rates.   

***
9kHz is the lower limit of the SA.  I think when we ran it with the scope, we were down below 10kHz before it fell off.    We did not try to collect data down this low. 
« Last Edit: December 21, 2021, 01:09:16 am by joeqsmith »
 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1403 on: December 21, 2021, 01:45:30 am »
Similar results when looking at a 3.68MHz crystal as the V2Plus4,  both poor.  No surprise.   OWO had mentioned a version of firmware that would allow the V2Plus4 to make narrow band measurements.  I never looked into it. 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1404 on: December 21, 2021, 02:16:44 am »
OWO had asked about using a short length of coax and looking at linearity.    Here I am using a M-M attached to a F-F  to create a small extension, calibrating at the end, then removing the extension.   Using the same settings,  I repeated the test with the V2Plus4.   

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1405 on: December 21, 2021, 02:56:31 am »
I was curious how the LiteVNA would handle the PDN measurements.  Shown with the homemade wideband common mode transformer measuring a 100mOhm, 25mOhm and 1mOhm resistor.   I will admit, I was concerned about the firmware causing a very poor low end response.  Keep in mind they only spec it to 50kHz.     

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1406 on: December 21, 2021, 03:17:43 am »
We had ran the unit much lower.  Here I have it set to 2kHz.   I then attach the 1mOhm and swept from 2kHz to 1MHz.   

I had looked at the noise floor and system dynamic range all the low cost VNAs I have.   I plan to repeat that with this unit and will post the results.  OWO was also asking about temperature stability so I'll drag out the meat packing box.

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1407 on: December 21, 2021, 04:53:31 am »
Looking at the noise floor, once we get beyond 100MHz the LiteVNA is worse than the V2Plus4.  As we get closer to 1.2GHz, the two are similar.   

The system dynamic range for the V2Plus4 is better than the LiteVNA.   Jan's VNA offers further improvements. 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1408 on: December 21, 2021, 04:57:44 am »
Sweeping from 1.5GHz to 3GHz, the noise is comparable.    The V2Plus4 seems to have better dynamic range.  Again, Jan's VNA offers further gains.   

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1409 on: December 21, 2021, 05:05:35 am »
Sweeping from 3GHz to 4.4GHz, the V2Plus4's noise is very comparable with the LiteVNA.   

The LiteVNAs system dynamic range is better as we get beyond 3.3GHz or so.   Note, data for the V2Plus4 was collected two ways.  One with the VNA powered from the PC, the other with it running from the internal battery.   I had ran a few tests and found any time I use any external power source with the V2Plus4, the noise goes up.   Even with a highly filtered linear supply.  I doesn't seem to matter and am guessing it is a problem with the design.   The LiteVNA does not appear to have this same problem. 

Offline Alextsu

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Re: NanoVNA Custom Software
« Reply #1410 on: December 21, 2021, 06:21:16 am »
Hi, Joe,
Thanks for sharing this results, very interesting!
Just a short remark concerning Jan's VNA port isolation tests, they are not up-to-date.
There had been found a workaround solution for the port isolation improvement at higher frequencies.
Also, there's a new discussion group, and actual info is posted there.
https://groups.io/g/LibreVNA-support
 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1411 on: December 21, 2021, 02:42:01 pm »
Jan had announced here when they had moved the group and about the problems they had with the account.   Seemed like a really bad business choice (using an unknown account if that's really what happen) but at least they now have it sorted.  I never joined the group after reading of all the shortcomings (no direct way to control the VNA without their software layer,  new hardware announced, higher cost, low frequency performance...).   

When we bought the two LiteVNA's, they were $130/ea on sale.  I think that's what I paid for the V2Plus4 when it first came out.   The price for the V2Plus4 was $200 last I checked.   I would assume the price for the LiteVNA will also increase over the next year.

After running the LiteVNA for about 4 hours last night,  I did not experience a single problem with it.  I was really concerned with Dislord's firmware.   I noticed they advertise for donations in the version menu for those wanting to help them out.   The version of firmware in this VNA is 1.0.70.   

I was unable to change the attenuator and assume it still doesn't have support for it which does seem a bit odd after Dislord's comment about adding it.   I'm guessing the problem is with my software and lack of documentation on how to implement it.

Offline Alextsu

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Re: NanoVNA Custom Software
« Reply #1412 on: December 21, 2021, 05:02:23 pm »
Jan had announced here when they had moved the group and about the problems they had with the account
 I never joined the group after reading of all the shortcomings (no direct way to control the VNA without their software layer,  new hardware announced, higher cost, low frequency performance...).   
Ok, understood.
How do you think,
In case I ask Jan to add support for standard V.2 command protocol to his SW, would You consider it possible to add it in Your SW?
 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1413 on: December 21, 2021, 06:32:21 pm »
Jan had announced here when they had moved the group and about the problems they had with the account
 I never joined the group after reading of all the shortcomings (no direct way to control the VNA without their software layer,  new hardware announced, higher cost, low frequency performance...).   
Ok, understood.
How do you think,
In case I ask Jan to add support for standard V.2 command protocol to his SW, would You consider it possible to add it in Your SW?
As long as the interface is well documented, then yes.  Obviously, it would require the hardware.

Offline DiSlord

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Re: NanoVNA Custom Software
« Reply #1414 on: December 21, 2021, 07:14:35 pm »
>I was unable to change the attenuator and assume it still doesn't have support for it which does seem a bit odd after Dislord's comment about adding it

You mean output power? This my temp V2 protocol format description:

V2 Binary protocol:
V2 contain 256 registers for read/write

On write to registers data put to reg[address] and V2 grab data and process (depend from address)

All values after in hex format!!!!
Commands for read/write
0x0D - read version (return "2")
0x10 - read byte
0x11 - read word
0x12 - read dword
0x13 - read qword

0x18 - read measured data (use 30 address for count)

0x20 - write byte
0x21 - write word
0x22 - write dword
0x23 - write qword
28 - write buffer (next byte data size, and data)

address:
0x00 - (qword) start frequency
0x10 - (qword) frequency step
0x20 - (word) points count
0x22 - (word) values pre frequency (need set to 1,

0x26 - (byte) mode (0 - USB mode, 1 - send raw data, 2 - normal mode)
0x30 - (byte) points for measure, or up to (measured values)

0x40 - (byte) average
0x41 - (byte) si power
0x42 - (byte) adf power

0x50 - (dword) color value
0x54 - (byte) color index (use H/H4 indexes)

0xee - (byte) any value, on write V2 send screenshot

0xD0 - (dword) SN[0] (serial number 0)
0xD4 - (dword) SN[1] (serial number 1)
0xD8 - (dword) SN[2] (serial number 2)

0xF0 - (byte) device variant (2 vor V2)
0xF1 - (byte) protocol version (1 vor V2)
0xF2 - (byte) board revision (2 vor V2, 3 - V2Plus, 4 - V2Plus4)
0xF3 - (byte) firmware major
0xF4 - (byte) firmware minor

Example:
Set average = 5 command:
0x20 - write byte
0x40 - address (average)
0x05 - value
Need send : 204005

Example:
Set SI5351 (<140MHz) power = 2 command:
0x20 - write byte
0x41 - address (Si power)
0x02 - value (0 - 3 value range avaible)
Need send : 204102

Example:
Set ADF/MAX(>=140MHz) power = 1 command:
0x20 - write byte
0x42 - address (ADF/MAX power)
0x01 - value (0 - 3 value range avaible)
Need send : 204201 (in hex bytes)
 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1415 on: December 21, 2021, 08:31:20 pm »
>I was unable to change the attenuator and assume it still doesn't have support for it which does seem a bit odd after Dislord's comment about adding it

You mean output power? This my temp V2 protocol format description:

V2 Binary protocol:
V2 contain 256 registers for read/write

....

Example:
Set SI5351 (<140MHz) power = 2 command:
0x20 - write byte
0x41 - address (Si power)
0x02 - value (0 - 3 value range avaible)
Need send : 204102

Example:
Set ADF/MAX(>=140MHz) power = 1 command:
0x20 - write byte
0x42 - address (ADF/MAX power)
0x01 - value (0 - 3 value range avaible)
Need send : 204201 (in hex bytes)

Yes, these both appear correct.   The version of your firmware supplied with the LiteVNA is 1.0.70. 

Are there other steps beyond having the frequency set that are required to change it?   Have you verified it works?

Offline DiSlord

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Re: NanoVNA Custom Software
« Reply #1416 on: December 21, 2021, 08:35:12 pm »
I not change V2 protocol in LiteVNA (only extend it) for allow existing software work.

I think about use NanoVNA v1 protocol, but not ready do this
 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1417 on: December 21, 2021, 08:57:08 pm »
That's fine.  Does the two examples shown actually work with the LiteVNA?   Have you tested them? 

Offline DiSlord

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Re: NanoVNA Custom Software
« Reply #1418 on: December 21, 2021, 09:05:35 pm »
I test LiteVNA control in NanoVNA-App software (add this feature to this app) all work. Avg setting / power for Si5351 (LiteVNA use MS5351 analog) and MAX2871

PS LiteVNA in < 400k work slow, it use less IF and need more time wait (i try think how possible improve this).
 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1419 on: December 21, 2021, 09:39:47 pm »
Thanks for confirming you have tested it.  I will have another look at my code and see if I can sort out where the problem is.     

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1420 on: December 22, 2021, 12:32:01 am »
I test LiteVNA control in NanoVNA-App software (add this feature to this app) all work. Avg setting / power for Si5351 (LiteVNA use MS5351 analog) and MAX2871

PS LiteVNA in < 400k work slow, it use less IF and need more time wait (i try think how possible improve this).
Set the start frequency to 200MHz followed by setting the step to 0 (200MHz CW).   Now try and change the  ADF's power level.    Repeat this at 100MHz with the SI's power level.   Now try repeating the above with the step of 1MHz rather than 0 to force the sweep. 

It seems that the power may only be set if the VNA is sweeping.  Let me know if you can replicate this. 
« Last Edit: December 22, 2021, 03:04:22 am by joeqsmith »
 

Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1421 on: December 22, 2021, 01:30:04 am »
Looking at the home made 70mm stepped airline with a sweep range of 1M-6.4GHz. 

Not sure of a good way to benchmark the temperature stability of the LiteVNA compared with the V2Plus4.   We want the contribution of the VNAs, not the loads and cables.   Seems like we would want to include both ports.   


Offline DiSlord

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Re: NanoVNA Custom Software
« Reply #1422 on: December 22, 2021, 03:17:37 am »
>It seems that the power may only be set if the VNA is sweeping.  Let me know if you can replicate this.
Yes, if nano not change frequency, new power setting not apply (i fix this in future fw update). So this command not work in CW mode.
 
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Offline joeqsmithTopic starter

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Re: NanoVNA Custom Software
« Reply #1423 on: December 22, 2021, 03:58:04 am »
It appears that the 23 +/-5C may be a common range they are tested over.   

For testing the two VNAs, I am thinking to place them together in the meat packing box, run two instances of the software and collect the data with a short section of Teflon coax between the two ports.  Maybe average the data down enough so we can see something.     This was a request from OWO so maybe they will chime in.   

***
They are suggesting S11 with a high return load (open or short) as they suspect there would be little error in S21.   We loose the other circuit.   I may have a look both ways. 


https://www.testforce.com/pub/media/sparsh/product_attachment/anritsu-MS2036C-datasheet_compressed.pdf
 
« Last Edit: December 22, 2021, 01:24:51 pm by joeqsmith »
 

Offline tungsten2k

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Re: NanoVNA Custom Software
« Reply #1424 on: December 22, 2021, 04:14:32 am »
Sweeping from 1.5GHz to 3GHz, the noise is comparable.    The V2Plus4 seems to have better dynamic range.

One obvious difference with the V2plus4 is the addition of a metal case which should reduce external noise floor somewhat, but would also increase internal reflection of noise from components within the VNA. The V2plus4 combats this by adding a layer of Radio Absorbing Material (RAM) to the entire back of the unit. In researching possible improvements in the LiteVNA to achieve system dynamic range parity with the V2plus4, I found this paper detailing the use of very common carbon fiber-filled 3D printer FFF filament for absorbing energy but at much higher frequencies that present in our VNAs, namely 63GHz-215GHz and observed in the neighborhood of -20db difference:

https://arxiv.org/pdf/1808.00820.pdf

Does anyone have a 3D printable case design that they would consider modifying with treatment similar to the paper (they used an open Hilbert curve infill, but I suspect even no infill but just using a 3D printable case with the appropriate CF-filled FFF filament should be enough to vet the idea).

Thoughts ?  If this is not on topic, I can start a new thread, but I'm really most interested in finding out if the LiteVNA can be made as good as the V2plus4 in the ranges the V2plus4 supports.

Thanks !

-=dave
« Last Edit: December 22, 2021, 04:18:17 am by tungsten2k »
 


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