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Good, possibly in future i add command for allow user set this correction.

Hello Dave,
Your screen shots does *not* tell the whole story.
72, Rudi DL5FA

BINGO !

After upgrading with your DFU file, i enter 100MHz in "CW" mode and

get 100.00010 MHz at the GPS locked frequency meter.

1 ppm instead of the initial -85.5 ppm !

Fine Job DiSlord and many thanks for your help and DFU file !

Best regards,

Rudi

I suggest you launch a kit for those who bought and did not have a small display.
Case + display module 4 inches + firmware.

Select target id
00 Internal Flash 64 sectors or

And press Upload

Then you upload file from NanoVNA programm read all flash 128kB and save to file
Then formware created, not used space not stored to file. 82kB correct file size

Yes it Ok

After reading the option "01", seems that you dfu file should be written into target option "00" (internal flash 64 sectors).

A 2nd point: NanoVNA v0.8.4.6 Xtail 25997748.dfu is 82 Ko but the uploaded file from my NanoVNA is 129 Ko , is this ok ?

Rudi

Hi DiSlord,

I installed DfuSe, connected to the NanoVNA after "Reset and enter DFU" activated;

on the DfuSe screen i have 2 Targets options:

-1- 00 Internal Flash 64 sectors or

-2- 01 Option Bytes??? 1 sector.

What is the correct target ?

Thank you for your help.

Rudi

A new technical support page for the NanoVNA-V2 is available at . I believe Gabriel posted here, or elsewhere, that the NanoRFE Foundation will be taking over the production of the V2. There is an "about us" page that gives details about the NanoRFE Foundation.

- Herb

Ed,

*1)* You've got a typo in your callsign: it should be KC1D*YK* (ROKBL!)

*2)* In terms of verifying the fundamental measuring impedance of the nanoVNA, that's a lot trickier. The essence of most VNAs is that the VNA is approximately correct, but to take an accurate measurement the VNA is compared to a set of reference impedances (the SOL calibration). [The nanoVNA S_11 bridge can be seen in the circuit diagram (schematic) for whichever model of nanoVNA you are using.]

*3)* Given that you are an M.Math, but I a mere subverter of otherwise pristine mathematics towards practical application (also known as Engineer), then you can probably imagine the system of matrices which make this more-or-less work.

*4)* On a very practical note, the cost of a good calibration set can, for good reason, easily exceed the cost of the VNA itself, since nanoVNAs are so very cheap, but accuracy is demanding.

*5)* I admire your experimenter's attitude of "Let's just measure it", which the nanoVNA readily allows one to do. The discrepancy that you've measured is one which, a few years ago, would simply have passed unnoticed, without access either to very expensive test gear, or to cheaper test gear that requires a slow manual process that few would undertake as a matter of course!

*6)* There is also the question of the impedance of CH1, for S_21 measurements, but that's a rabbit hole for another day.

*7)* In short, the measurements that one gets from the nanoVNA are only as good as the calibration references in use. Or if one prefers, the numerical results from a VNA directly come from the calibration set used for those measurements. The numbers *are* the calibration. [That's the essence of it.]

HTH, 73, Stay Safe,

Robin, G8DQX

Hi just spent a UK windy afternoon confined to my radio 'shack' , so decided to upgrade the screening on my 'basic' clone nanoVNA to see if the INPUT 'noise' could be reduced.
I made the screens out of some 'shim' brass foil and formed them round some srbp (Tufnol) formers THAT I made first.
I am pleased with the improvement that just a couple of hours 'metal bashing' has produced.
Hopefully this will inspire others to have a go?
Dave

Thank you very much DiSlord for your help and work.

I will install this file this afternoon and inform you for the result.

Regards,

Rudi

30Hz in 100MHz.

That is just 0.00003% low in frequency.

For the money we spent, why would anybody not be satisfied with that?

I'm still happy with the accuracy of my Grid Dip Meter.

73, Alek, VK6APK.

May I ask, what is the assembly house of Saa V2? It has small chips, 4 layer board and components on both sides of the board. All these could make an expensive boards but apparently it is not expensive.
Regards
Leif M

This is a different device.

100 mHz, 299 mHz.

Try this firmware, just quick build vs XTALFREQ 25997748

Hello,

For the moment, my friend has no access to the labo for component replacement (virus).

I would try your XTALFREQU modification but i'm not able to modify and recompile your software.

How can i proceed, may be with an other FW including the OFFSET command not active

on my NanoVNA-H ?

Thank you for helping me.

Regards,

Rudi

After searching for this component numbering, i found nothing at LCSC.

I've done many frequency measurements and? had a great drift with temperature.

May be it's not a TCXO but a XO with +/- 100 ppm tolerance ?

Just an idea..

Regards,

Rudi

At this time code very dirty and contain a lot of debug and test info and i not add it to git (if need i can send code on mail), at this time it only of 'proof of concept'

SD card support need only ~8-9kB for FatFS vs long filenames (possible reduce size on 3kB if use old DOS format 8.3 names)
RTC need additional 1kB (most of code for convert/user input output)
Low level functions for init/read/write SD card need ~2kB
FatFS need ~1.5kB of RAM (possible reduce to ~800bytes)

512 bytes for file directory search read buffer
512 bytes for read/write buffers (FatFS allow use directory search buffer for this)
and about ~200 bytes for

At begin i try use another lib for filesystem support like PetitFS

It size only ~2kB and need 600byte of Ram (512 read/write buffer can removed, but it huge reduce read/write speed all data need read every time), but have very limited create/write file support

VinxFS - possible better, but i not test it

So at this time need only ~12kB flash and 1.5kB Ram (i think possible also add this to NanoVNA - H it have ~14kB free flash and possible free ~1kB ram from spi buffer or use it)
Possible not use filesystem and use direct sector read write, it huge reduce code size, but need add additional PC mode/soft for get data from it.
Also not added USB support for use NanoVNA as card reader (USB still in Serial mode)

Gyula Molnar search LCSC and I found some slot variants: XUNPU TF-115K and THD THD2528-11SD-GF

Need search

microSD? Memory Card "connector&Ejector"

option for easy insert and remove card (use Push In，Roll out option)

On Fri, May 22, 2020 at 04:10 PM, Larry Rothman wrote:

DiSlord,
This absolutely fantastic!? How much free flash is left over now for other
enhancements?
As for the card detect switch, can you use one of the spare pins on the uP as
a sense input from the card slot switch? That way, you can verify quickly if a
card is present.
Please add the code to your GitHub repo (if not there already) as I would like
to see how you implemented this.
Thanks!
Larry