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S-A-A-2 Programming Problem #nanovna-v2

 

erik,
I've been trying to transfer some of my NanoVNA scripts over to the S-A-A-2, and although its communicating, I'm operating blind. Any remote commands to the S-A-A-2 cause the screen to go white with the a "NanoVNA V2_2 USB MODE" message. There doesn't seem to be a command for exiting the USB Mode and the S-A-A-2 stays in that mode even after closing the serial port and exiting a script. The only way I have been able to exit the USB Mode and get back to a normal screen is by cycling power to the S-A-A-2.

Have you been able to find a reset or change mode command while modifying TAPR? Cycling power is not elegant. Actually, exiting the NanoVNA-QT program leaves the S-A-A-2 in the same state, which, is not the way to treat the user. This doesn't seem like Gabriel's usual attention to detail. In this area I would score one for the NanoVNA. I left an issue report at the GitHub page.

It also looks like the S-A-A-2 does not transfer corrected data over USB. Any external program or script will need to apply its own correction data. I don't envy Rune's effort to port NanoVNA-saver to this device. The communications protocol is totally different from the NanoVNA. Even enumerating the serial port required code changes, at least on my windows PC.

Additionally, it appears Gabriel decided to enforce re-calibration if the user changes frequency range. No more interpolation allowed. That's probably a good thing, but will puzzle some prior NanoVNA user's.

- herb

- Herb

- Herb
 

btw the V2 team is not just me ;) I'm just the only one publicly talking about it and even then I don't use my real name ;)

I can confirm that currently the only way to exit USB mode is to toggle the power switch. I'll look into adding a register to allow changing modes.

The USB interface always outputs raw, uncalibrated values, as is in the user manual. The reason is the assumption that the PC software always has superior calibration routines (e.g. supporting arbitrary cal kit parameters) and it is far less error prone if you can't be confused whether you are reading calibrated or uncalibrate values.

The VNA logic in the firmware was written from scratch, and we haven't yet implemented calibration interpolation (it wasn't removed, just never implemented). Personally I've not had good experience with using interpolation on other VNAs that support it; I've found it to give wrong results every time unless you have an insanely high number of sweep points (1000). However if there is popular demand we can go and implement interpolation.
 

That sure makes for some mystery, Gabriel! Why do you use a pseudonym?

Randy
NC8U

On Mar 28, 2020, at 9:53 PM, Gabriel Tenma White <OwOwOwOwO123@...> wrote:

btw the V2 team is not just me ;) I'm just the only one publicly talking about it and even then I don't use my real name ;)

I can confirm that currently the only way to exit USB mode is to toggle the power switch. I'll look into adding a register to allow changing modes.

The USB interface always outputs raw, uncalibrated values, as is in the user manual. The reason is the assumption that the PC software always has superior calibration routines (e.g. supporting arbitrary cal kit parameters) and it is far less error prone if you can't be confused whether you are reading calibrated or uncalibrate values.

The VNA logic in the firmware was written from scratch, and we haven't yet implemented calibration interpolation (it wasn't removed, just never implemented). Personally I've not had good experience with using interpolation on other VNAs that support it; I've found it to give wrong results every time unless you have an insanely high number of sweep points (1000). However if there is popular demand we can go and implement interpolation.
 

Gabriel,

What program did the team use to simulate the PCB with the various components? I want to simulate (initially) some lumped component (SMD L and C) filters till 1GHz on a double sided FR4 PCB and looking for a free tool with an acceptable learning curve.
I found Ansoft Designer SV but that requires some study time. Can you recommend something?

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK
 

On Sat, Mar 28, 2020 at 09:53 PM, Gabriel Tenma White wrote:
I can confirm that currently the only way to exit USB mode is to toggle the power switch. I'll look into adding a register to allow changing modes.

The USB interface always outputs raw, uncalibrated values, as is in the user manual. The reason is the assumption that the PC software always has superior calibration routines (e.g. supporting arbitrary cal kit parameters) and it is far less error prone if you can't be confused whether you are readin calibrated or uncalibrate values.
=============================================================
Gabriel,
Thanks for your response. I understand blanking the display while NanoVNA-QT or similar programs are running to increase the speed of data transfers. Plenty of commercial applications do the same thing. For small scripts, where you just want to work with the trace data currently on the display, it would really help if you could add a firmware command to un-blank the display, and also a firmware command to transfer corrected CH0 and CH1 data.

Do you know it the client, HCXQS group, plans on a support forum for the S-A-A-2?

Regards,

- Herb
 

Hi there,

Do you think a specific groups.io group would help?

I have created one already, as I am waiting for my unit, but I am not sure
if its impolite to mention it here.

*73 de ³¢³Ü¨ª²õ, CT2FZI*




<>

On Sun, 29 Mar 2020 at 17:42, hwalker <herbwalker2476@...> wrote:

On Sat, Mar 28, 2020 at 09:53 PM, Gabriel Tenma White wrote:
I can confirm that currently the only way to exit USB mode is to toggle
the power switch. I'll look into adding a register to allow changing modes.

The USB interface always outputs raw, uncalibrated values, as is in the
user manual. The reason is the assumption that the PC software always has
superior calibration routines (e.g. supporting arbitrary cal kit
parameters) and it is far less error prone if you can't be confused whether
you are readin calibrated or uncalibrate values.
=============================================================
Gabriel,
Thanks for your response. I understand blanking the display while
NanoVNA-QT or similar programs are running to increase the speed of data
transfers. Plenty of commercial applications do the same thing. For small
scripts, where you just want to work with the trace data currently on the
display, it would really help if you could add a firmware command to
un-blank the display, and also a firmware command to transfer corrected
CH0 and CH1 data.

Do you know it the client, HCXQS group, plans on a support forum for
the S-A-A-2?

Regards,

- Herb
 

On Sun, Mar 29, 2020 at 11:27 AM, CT2FZI wrote:

Do you think a specific groups.io group would help?
==============================================
³¢³Ü¨ª²õ,
So far only about 150 S-A-A-2 units appear to have been sold before the first production run ended. I don't know if that is enough volume to warrant another user group, but only time will tell. This groups.io forum and the NanoVNA Facebook page also support the S-A-A-2. If you can get the S-A-A-2 manufacturer to designate your forum as an official support site that would be advantageous.

- Herb

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