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Hi Erik
Thank you for the spreadsheet
I did mistakenly comment your T-Check to Reuters and did right away see the mistake
I imported your s2p file after modification of the header, as a surplus S at the end in the # HZ S RI R 50
Good question where is came from :::
As seen on the plot 50% at 800MHz and should be better tha 5% for an acceptable calibration. The reason is the missing error correction and by adding 10dB SMA inline attenuation on either side of the T-Check adaptor might improve as the Ch0 and Ch1 source/load impedances are not 50ohm
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af erik@...
Sendt: 5. november 2019 18:54
Til: [email protected]
Emne: Re: [nanovna-users] T-Check for my nanoVNA - Results look excellent below 150 MHz and acceptable up to 300 MHz

Attached spreadsheet contains the formula and you can paste your s2p file on the input tab

--
Erik, PD0EK

Hi Reuter
I had to modify your header to import the s2p file. There was a S too much
! ListType=Lin (This addition was probably not needed)
# HZ S RI R 50 (at the end of this line there was a S too much)
As you see your T-Check is peaking of 50% at 800MHz and should for an acceptable calibration be less than som 5%.
Reason is the your measurements is not error corrected and if you add two 10dB SMA inline attenuator on either side of you T adaptor then it might work
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af reuterr@...
Sendt: 5. november 2019 18:10
Til: [email protected]
Emne: Re: [nanovna-users] T-Check for my nanoVNA - Results look excellent below 150 MHz and acceptable up to 300 MHz

On Sat, Oct 5, 2019 at 06:39 PM, <bryburns@...> wrote:

I then used the T-Check equation found on page 12 of the file
"Reeve_S-ParamTestSet.pdf" found at

.
pdf

to compute the T-test result as a function of frequency which is
plotted in the attached ".jpg" file.

Hello Bryan,
I am trying to calculate the T-Check value from the NanoVNA-Saver .S2P file with LibreOffice Calc, but I did not got the T-Check formular adopted.

I then copied S11 to S22 and S21 to S12

This is already done in the attached file T-CheckR31.S2P I attached also a screen shot from NanoVNA-Saver T-Ceck measurement.
The 49.85 Ohm resistor was soldered in a SMA Female-Female Adapter, see attached photo T-Check_SMA-F-F_49.85Ohm_DSC08169.jpg

Could you please explain in detail how you applied the formular?

73, Rudi DL5FA

#73 :

erik@... - 5 November 2019 : /g/nanovna-users/message/6495

Dear Erik,

Thank you very much indeed for your interest in our work and also for the
chance you give us to explain it -always facupov, of course- further !

Therefore, regarding your specific question:

"How are you sure the errors to be corrected are larger than the uncertainty in
your measurement. e.g. you are not trying to correct an already (almost) perfect
VNA?"

allow us, please, to definitely clear without any doubt that in our sow [#24], [#34]
we are only * c u r r e n t l y * sure for the following - but we hope to excuse us
because, maybe unfortunately enough, we selected to explain all that using
purposely a greatly emphatical language:

- - - - - - (c) gin&pez@arg (cc-by-4.0) 2019 : start - - - - - -

(0) "A perfect VNA" is an object of the * i m p e r f e c t * world of mathematics

(1) "An already (almost) perfect VNA" may be an object in other subjective worlds
- we don't know, but we are ready to include it in our sow, as soon as we will be
provided by the specific quantitative data of its existence

(2) "The Least VNA" is simply AnyVNA that is used as a Reflectometer or
Impedance Meter in terms of frequency of One-Port devices using the well-known
("standard", 'Standard' or Standard) set of three 3 loads {S, L, O}, all with known
nominal values given respectively, not at all by us but by their manufacturers, as
the so-called "{-1, 0, +1}" or whatever similar

[ but loosely, because this may be result in a * B I G * source of misunderstanding
[ since this "set of values" is in fact the one of the couples of values:
[
[ { ( 1 , -180 ) , (0 , undefined ) , ( 1 , 0 ) }
[
[ in terms of their ( modulus , argument ) ordered
[ -
[ that is in order to avoid to mess up the things, the modulus value has always to
[ appear first, after the opening left parenthesis and before the separating comma,
[ and then the second argument value to appear before the closing right parenthesis
[ -
[ pairs or couples of values

although a last -apt, as usual- comment made by our Fellow in Knowledge Garry
O' Neil, N3GO [1], forced us to already think a possible reconsideration of this
definition in the direction of an even more simplification; always facupov, of course

(3) "The LeastVNA measured Impedance" is * I N * F A C T * an * I N D I R E C T *
"measurement", that is a * C A L C U L A T E D * or * C O M P U T E D * result,
just an * O U T P U T * of the well-defined * M A T H E M A T I C A L * function
expressed by the well-known * F O R M U L A * [#52]:



in terms of the measurements of these * T H R E E * loads, made * D I R E C T L Y *
using that * A N Y * V N A *

(4) Obviously this is an * I N S E P A R A B L Y * A S S O C I A T E D * to * A N Y *
* V N A * mathematical expression, a so-called "(mathematical) model", of this
very instance LeastVNA of that AnyVNA.

(5) We did * N O T * invent this relation [#52]:



We just simplified the given one [#16]:



-
as perhaps they did that others before us, although we don't know if something that
really happened.

This is easily verified by anyone who would like to use simple, high-school algebra
on these expressions, by ignoring their complex "nature" and substituting:

(i) g, G in Hellenic gamma, Gamma

(ii) -1, 0, 1 in A, B, C, and

(iii) s, l, o in a, b, c,

respectively, and proceeding with the resulting eliminations.

That's all.

(6) Now, since the 8 = 3 x 2 + 1 x 2 measurements s, l, o, and g, were indicated by
our VNA to us with a * F I N I T E *, * L I M I T E D * * A C C U R A C Y * of just
* T H R E E * 3 *, or * F O U R * 4 * at most, decimal * D * I * G * I * T * S *, it was
extremely natural in our sow to ask ourselves :

HOW BIG WILL BE THE EFFECT IN THE UNAVOIDABLY * C O M P U T E D *
IMPEDANCE, IF WE WOULD TAKE INTO ACCOUNT THAT *J U S T * O N L Y *
O N E *, THE LAST ONE, DIGIT OF THESE FOUR MEASURED VALUES WAS IN
DOUBT ?

THAT IS AS IT HAPPENS IN ANY OTHER MEASUREMENT, BY ANY OTHER
INSTRUMENT, SO WHY NOT WITH THOSE BY AnyVNA OR OUR VNA ?

That's all..

And, once again, definitely this has nothing to do with the perfectness or imperfectness
of AnyVNA itself. But, this definitely has to do with the unavoidably finite number of
reliable digits used by AnyVNA to indicate its measurements.

And this finite number of reliable digits in these four 4 measurements is only JUST
ONE source of error in the finally COMPUTED indirect "measurement".

(8) We emphasized in the above the COMPUTED character of the indirect
"measurement" because, if this INDIRECT "measurement" was a usual DIRECT
measurement, all the doubt would unavoidably restrict to just a few, perhaps even
only the last one, of its resulted digits - but, unfortunately enough, this is not the
case here.

(9) Also, and in addition to all that, the range of measured values (small, less than one
1 in modulus), as well as the particular form of the unavoidable mathematical
expression (ratio of differences of small, less than one 1, in modulus values) FORCED
us to attempt such a research
-
and it would be the GREATEST of OMISSIONS by us, if we did not act in this way,
as long as we declared ourselves not only as "researchers" but in addition as "scientific"
ones...

(10) After all that said, we think that we are ready to answer your question as follows:

- We are NOT interested to correct our "measurement" -in fact one of our VNA itself

- We are NOT interested if the errors to be corrected -in fact ones of our VNA itself-
are larger than the uncertainty in our "measurement" -in fact in the computed indirect
"measurement" of our VNA itself

- We are only * c u r r e n t l y * s u r e * that our method of estimation of the above
inaccuracy errors, which * U N A V O I D A B L Y * C O N T R I B U T E * to the
ENTIRE "MEASUREMENT" UNCERTAINTY of our two VNA systems
-
that is either of our VNA or of our * N a n o V N A *, * P L U S * our THREE Standards
and just in this, the simplest of all the possible cases, also "currently the simplest",
after our reservation (2) above, that is after Garry O' Neil's comment

- We are * c u r r e n t l y * s u r e * that our method of estimation of all the errors we
are currently in place to recognize as REALLY EXISTING in AnyVNA measurements,
that is the above Inaccuracy Errors PLUS those definitely larger than these
Uncertainty Errors given to our three 3 Standards by their manufacturers, all together
count 8 + 3 x 2 = 14, contribute UNAVOIDABLY to the ENTIRE "MEASUREMENT"
UNCERTAINTY of our two VNA systems

And this is the reason we call them :

"The Uncertainty Core" - at least of our two VNA and NanoVNA Systems -

In conclusion:

* UNCERTAINTY * LESS * THAN* THAT * IS * ENTIRELY * IMPOSSIBLE *

in AnyVNA SYSTEM and at least in its LeastVNA application - fullStop.

- - - end : (c) gin&pez@arg (cc-by-4.0) 2019 - - - - - - - - - -

* You * Have * Been * Warned *

REFERENCES

[1] Gary O'Neil , N3GO - 4 November 2019 :
/g/nanovna-users/message/6432

[#16] : 27 September 2019 :
/g/nanovna-users/message/3161


[#24] : The Main Frame of a Possible Communication - 1 October 2019:
/g/nanovna-users/message/3649

[#34] : Trying to Limit the Misunderstanding up to its Removal - 5 October 2019:
/g/nanovna-users/message/4108

[#52] : Update : The compact SLO formula for [AnyVNA] - 17 October 2019:
/g/nanovna-users/message/5100


With our Best of Regards,

73

Nikolitsa, OE3ZGN/SV7DMC and Petros, OE3ZZP/SV7BAX

: 73#

Hope someone can give me some insight on the TDR impedance measurement display. I have attached TDR impedance displays for two cable assemblies.

The first cable assembly was made up of a 0.3m length of RG-174, connected to a 1m length of RG-223 that was terminated in a 50 ohm load. The TDR impedance measurement display showed a 50 ohm impedance step for the RG-174 cable and then another slight impedance step for the terminated RG-223 cable. Pretty much what I was expecting.

The second cable assembly was made up of a 0.3m length of RG-174, connected to a 200 ohm coaxial feed-thru, connected to a 1m length of RG-223 that was terminated in a 50 ohm load. The TDR impedance measurement display showed a impedance step for the 200 ohm feed-thru but never stepped back down for the 50 ohm terminated RG-223 cable.

Am I misunderstanding how the second cable assembly should be shown on the TDR impedance measurement display?

BTW, really appreciate the capabilities Rune continues to add to NanoVNA-Saver. Just trying to wrap my head around the new TDR impedance measurement display.

- Herb

Thank you, that is usefull information for everyone!

I haven't decided what to do. I might fix my nanoVNA, buy another or wait for the announced "nanoVNA 2.0". My version isn't completely dead but the pc-usb interface stopped working, which I think is caused by a bad usb connector. My nanoVNA lacks RF shielding (unlike yours) and comes with a simple enclosure (like yours). I would like to have a better enclosure, because I like the NanoVNA and would love to keep it working.

If RF-shields and/or enclosure is available for not to much I would like to hear about that too.

You'll need a tool chain that produces the smallest binary.

Eventually, but getting something built first in a "friendly" IDE,
then whittling to fit, might be faster.
Also, with Bluetooth, local display becomes highly optional.

Hello Erik,
Now it works, see the attached diagram: NanoVNA_T-Check.png
Thanks again for the very good spreadsheet.
73, Rudi DL5FA

Actually, read the whole thread, including /g/nanovna-users/message/1795

With all the features stuffed into the current firmware, builds are starting to overflow storage.
You'll need a tool chain that produces the smallest binary.

On Tuesday, November 5, 2019, 2:02:14 p.m. GMT-5, Oristo <ormpoa@...> wrote:

> In fancy words - I need to integrate Eclipse GUI with NanoVNA "stuff"

/g/nanovna-users/message/1508

are there SPI to BT modules?

Oops, just found this article:


.. which recommends HC-06: "use it simply for a serial port replacement"
~ US$1.40

I mean to rip the BT module out of the device...
Also, I just had a quick look at the pin mapping of the F072 as used in the NanoVNA.?

PINS 30 & 31 (not currently used) can be remapped to USART1_TX & RX respectively.?

A 'little code' and a new soft-switch under the Config menu could be set up to switch all console between either USB or Serial.

On Tuesday, November 5, 2019, 1:48:40 p.m. GMT-5, Oristo <ormpoa@...> wrote:

> I was thinking a little more on what uses a serial to BT bridge

I do not find hacks turning ELM327 into BT bridge;
cheap HC-05 has good Arduino support,

but wants substantial code.

A "smart" BT LE shield is ~$20

Hello Erik,
Thank you very much for your provided spread sheet.
At the moment I am still fighting with the decimal point/comma topic :-(
73, Rudi DL5FA

I was thinking a little more on what uses a serial to BT bridge

I do not find hacks turning ELM327 into BT bridge;
cheap HC-05 has good Arduino support,

but wants substantial code.

A "smart" BT LE shield is ~$20

are there SPI to BT modules?

Yes, but SPI to USB host would be simpler
than trying to add Bluetooth to nanoVNA firmware

Actually, I was thinking a little more on what uses a serial to BT bridge: every one of those really cheap OBD2 BT car diagnostic readers has one built-in.
Those readers cost $5 and up so the BT boards they use should be $1-2.?

So - now let's look at how to make re-use? of the STLink pins to drive it.....
...Larry

Oristo,
All Vaclav needs to do is use one of the unused serial ports on the chip and use a BT to serial module.
I was looking at the F072 specs and it appears the serial pin I was thinking if using is also used as an SPI line (are there SPI to BT modules?)
Can one of the STLink lines at the edge of the PCB be reprogrammed for serial?
...Larry

Hi Vaclav -

I am planning to add Bluetooth USB dongle ( hardware) to MY NanoVNA, including
necessary software.

Unless you find a Bluetooth dongle that supports USB OTG, I think that this is doomed.
I found no 64-pin STM32 chip, as in nanoVNAs, that does USB OTG,
/g/nanovna-users/message/5373

...resulting in a classic "failure to communicate".

Herb, thanks very much. I assume the two devices are different enough that the manual for the smaller one will not be of help. I almost purchased the smaller one but thought why not get the larger one....easier to see and work with. So far, all I have done is charged it.....hopefully....I think lol

Attached spreadsheet contains the formula and you can paste your s2p file on the input tab

--
Erik, PD0EK

This is sort of "bump" / dupe.
Or more direct approach.
Take your pick.

This is NOT post for / to users of NanoVNA,
This post is about NanoVNA operating / embedded software hacking.



I am planning to add Bluetooth USB dongle ( hardware) to MY NanoVNA, including necessary software.

I have dissected current NanoVNA Open source software and used git clone to add it to my local repository.
I am using Eclipse with EGit plug-in and have it somewhat under control - with one exception - I do not know to to "build" / test verify the software using local repository BEFORE flashing it in NanoVNA .


In short - I could use some help from anybody trying same - develop / modify etc. original software.

At this point I do not need git tutorials, I am past that point and feel comfortable with git.
I also do not want to do CLI. I already got that pretty much working - using source "makefile".


In fancy words - I need to integrate Eclipse GUI with NanoVNA "stuff"

Sorry for taking bandwidth here.

73 Vaclav AA7EJ