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#60 : @ Gary O'Neil - 17 October 2019:
/g/nanovna-users/message/5075

Dear Gary,

Allow us, please, to reply your most valuable comments and suggestions
as follows:

C1-GN : 1st Paragraph : "Your #51 full" ... "you have presented."

A-G&Z : On the known and most understandable difficulty of following links :

- Are you sure that you really read instead of #50:

/g/nanovna-users/message/5061

its online content, contiguously including all the Figures, here:


61 - [NanoVNA] ~ [ VNA] - Πω? Κ?ναμε την Σ?γκριση - 17 Οκτ 2019, 00:57

where, except just three 3 non-English, title and salutation lines which you can
ignore of course, there are only a few, non-essential, links ?

Why do you not save this html page for comfortable off-line view ?

C2-GN : 2nd-4th Paragraphs : "I believe you presented [... ] of being FACUPOV"

A-G&Z (a) : On the [openwatcom-fortran][1.9]:

- What do you mean by "shadowed" ? The link at:

ftp://ftp.openwatcom.org/install/open-watcom-f77-win32-1.9.exe

is alive and this download of 66,473,025 bytes is still a working one.

A-G&Z (b) : On the FORTRAN in general:

- But, if you do mean that FORTRAN is no more "in trend" or "in fashion",
then there is only a little that we can do about it and definitely to not
dispute your points : 1) - 6) , which are simply a matter of taste.

C3-GN : 5th-10th Paragraphs : "If I may suggest [...] Linux version"

- Thank you very much ! We can assure you that we already took into
account all that, as it may be reflected, as we hope, in the messages
we sent meanwhile to the group.

Best regards,

gin&pez@arg

60#

@Oristo - Is my understanding correct that if I select "Reset" and then proceed with a calibration, ALL previously stored Cal data is cleared? Now if I make a fresh calibration for a different frequency range, (different from C0 which is my default) is it correct to just carry out the full cal without selecting "Reset" and saving the new Cal data to a new memory location?

Here is an example for gnuplot line colors:

Hi Rudi

First of all the use of the testcables from the NanoVNA female SMA adaptor (the SMA male female adaptor saver) to the reference plane is a bad idea. The female female adaptor used during calibration has loss and has influence on the sweep of the semirigid cable sweep so the sweep run outside the Smith chart. Adding the female female adaptor at the end of the semirigid cable is also wrong as the loss in the female female adaptor again creates a wrong trace around the Smithchart. The female female adaptor supplied with the NanoVNA has in particular high loss and any other female female adaptor has some loss to account for.
So do the following:

Directly at the VNA SMA female Ch0 adaptor do a S11 calibration (do not use the supplied open adaptor) and connect you semirigid cable directly afterwards and leave the far end unterminated. Ideally the semirigid cable should end blindly but the SMA male adaptor has little effect loss wise, but it is there despite small and hardly detectable. The big bug is the female female adaptor you must not connect as you did.
When dealing with the N calibration kit then use a SMA male to N female adaptor and at first directly connected to the NanoVNA Ch0 female adaptor. Afterward you may experiment with adding test cables and do the calibration from there where you are forced to use the female female adaptor or better a SMA female to N female adaptor.

Use the NanoVNA saver feature to save the first sweep directly on Ch0 to "Save as Reference" as you then can compare step by step what you are doing.

Do not expect the NanoVNA to beat a more advanced VNA, it still has some shortcoming and you got a version which is characterized by some as a bad clone ?

Kind regards

Kurt



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af reuterr@...
Sendt: 20. oktober 2019 10:02
Til: [email protected]
Emne: Re: [nanovna-users] The Male Calibration Kit for AliExpress



Hello Kurt,

Thank you very much for taking care about my question.

I will write my answers below your questions.



On Sat, Oct 19, 2019 at 10:56 PM, Kurt Poulsen wrote:

1. Did you use a male SMA to N female adaptor directly fitted to the

SMA

No.

female adaptor for Ch0 ?

Just a male-female thread saver, as could be seen on the photo.

2. Did you before using the NanoVNAuser ensure the NanoVNA was

correctly calibrated directely at the NanoVNA Ch0 female adaptor with

the supplied calibration kit ?

The nanoVNA was calibrated at the *Reference Plane* shown in the photo.

The used *Calibration Kit* was the supplied one.

The *Open* SMA part was replaced with a *female-female adapter*.

2a. and did a sweep of a 25 to 50cm SMA test cable show better result?

I can not understand the question.

3. The test cable is probably too long and shall be a N type cable

with no adaptors fitted

I do not have that.

4. Your NanoVNA has a poor bridge as NanoVNA as far as I know has no

internal error correction

I measured the 50 Ohm resistance with a 3 VDC supply and a 4 digit *Ampere meter* and *Volt meter* The nanoVNA CH0 port shows 49.23 Ohm.

The 50 Ohm load shows 50.72 Ohm.

A self made 50 Ohm load from 2 SMD 0805 100 Ohm 1% resistors in parallel shows 49.99 Ohm (interesting).

There is probably more reasons and it would be better if you explained

in details you setup

Please see the attached photo: nanoVNA_50cm-RG402-open2_f-f_DSC08152.jpg

I have attached 2 screen captures from nanoVNA-saver with the S11 measured 50 cm RG402 coax cable.

nanVNA-Saver_50cm-RG402-open2.png - End of RG402 SMA male plug open nanoVNA-saver_50cm-RG402-open2_f-f.png - End of RG402 male plug with *female-female adapter* It is interesting how much the *Parallel X* capacity changed.



The nanoVNA-saver has an additional calibration with 5 segments.



What can I enter in the window Calibration->Calibration standards in order to improve the measurement?

73, Rudi DL5FA

Hi Rune -

I just tried it with a different plot I have a script
making hourly plots, 1024x768 pixels. .gif is 18547 bytes, .png is 14244
bytes. So I definitely see .png being smaller.

Oops, thanks for testing. Before Smith charts,
my gnuplots were smaller by gif than png,
and I did not think to recheck.

On Sun, 20 Oct 2019 at 11:12, Oristo <ormpoa@...> wrote:

set terminal png size 1000,1000

gif will be smaller than png

That's interesting. I just tried it with a different plot I have a script
making hourly plots, 1024x768 pixels. .gif is 18547 bytes, .png is 14244
bytes. So I definitely see .png being smaller.

(Also, if you set it to gif, you end up with a gif file, which you probably
wouldn't want anyway. ;-)

--
Rune / 5Q5R

i cannot save correct cal data to any location other than C0

Do new calibrations not work immediately after creating?

Run RESET before any calibration or to run uncalibrated.

nanoVNA always loads C0 (if saved) at power-on;
use RECALL to load any other saved calibrations.

WSL doesn't have X Windows support

VcXsrv works for me with WSL since 2017

set terminal png size 1000,1000

gif will be smaller than png

set linetype 1 lc rgb "gray60" lw 1 pt 1
set linetype 2 lc rgb "red" lw 2 pt 1

Thanks, I forgot to update color coding.

gnuplot works fine directly from Windows cmd.exe


I use a bat file to set a custom PATH when using gnuplot from cmd.exe:

C:\Users\ormpoa>type gnuplotPath.bat
path=C:\Program Files (x86)\gnuplot\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\WindowsPowerShell\v1.0

Hi Rune,
thanks for your kind offer, S21&S11 on the same plot is for sure good enough!?
Kind regards
Norbert, DG1KPN

Don’t you feel that the Smith Chart is *far* away from the original posters
question about things for *beginners*? The original poster suggested
finding the resonate frequency of an antenna.

Smith charts show resonances, where plots crosses horizontal axis.

a quick skim read indicated no reference to what the x & y axes are,
which is something I have noticed with several descriptions of the Smith Chart.

Sad, because Smith chart simply plots S11 reactance vs resistance.

Oristo, thanks for that link.
I was thinking of trying to roll my own transformers. Maybe using 30 AWG wire wrap wire.

Measuring transformers of dubious provenance and hand-wound motivated
my nanoVNA.
I find color-coding helpful, e.g.

Hello Norbert,
I responded to your previous email on the same subject on Thursday:

Hi Norbert,
I'll definitely not make a flexible display window for now, as the way the
charts are built is not at all compatible with this approach - sorry! Maybe
in a far future when everything is refactored. :-)

Making a plot of both S11 and S21 LogMag on the same chart wouldn't be too
much work, so I might be able to do that. I'll put it on the list!

--
Rune / 5Q5R

Hi Rune,
I have a suggestion. If one tries to adjust a homebrew filter of any kind it would be very helpful to see the result of the adjustment at least for S21 and S11 simultaneously on one plot. In other words, could you please make a flexible window where one could select various data to be displayed on that window simultaneously?

Kind regards
Norbert, DG1KPN

Hello Kurt,
Thank you very much for taking care about my question.
I will write my answers below your questions.

On Sat, Oct 19, 2019 at 10:56 PM, Kurt Poulsen wrote:

1. Did you use a male SMA to N female adaptor directly fitted to the SMA

No.

female adaptor for Ch0 ?

Just a male-female thread saver, as could be seen on the photo.

2. Did you before using the NanoVNAuser ensure the NanoVNA was correctly
calibrated directely at the NanoVNA Ch0 female adaptor with the supplied
calibration kit ?

The nanoVNA was calibrated at the *Reference Plane* shown in the photo.
The used *Calibration Kit* was the supplied one.
The *Open* SMA part was replaced with a *female-female adapter*.

2a. and did a sweep of a 25 to 50cm SMA test cable show better result?

I can not understand the question.

3. The test cable is probably too long and shall be a N type cable with no adaptors fitted

I do not have that.

4. Your NanoVNA has a poor bridge as NanoVNA as far as I know has no internal error correction

I measured the 50 Ohm resistance with a 3 VDC supply and a 4 digit *Ampere meter* and *Volt meter*
The nanoVNA CH0 port shows 49.23 Ohm.
The 50 Ohm load shows 50.72 Ohm.
A self made 50 Ohm load from 2 SMD 0805 100 Ohm 1% resistors in parallel shows 49.99 Ohm (interesting).

There is probably more reasons and it would be better if you explained in details you setup

Please see the attached photo: nanoVNA_50cm-RG402-open2_f-f_DSC08152.jpg

I have attached 2 screen captures from nanoVNA-saver with the S11 measured 50 cm RG402 coax cable.
nanVNA-Saver_50cm-RG402-open2.png - End of RG402 SMA male plug open
nanoVNA-saver_50cm-RG402-open2_f-f.png - End of RG402 male plug with *female-female adapter*
It is interesting how much the *Parallel X* capacity changed.

The nanoVNA-saver has an additional calibration with 5 segments.

What can I enter in the window Calibration->Calibration standards in order to improve the measurement?
73, Rudi DL5FA

QRP RX, didn't ever find that $3.00 price on eBay, your search skills must be better than mine. I did find a picture/ schematic though.

Oristo, thanks for that link. I was thinking of trying to roll my own transformers. Maybe using 30 AWG wire wrap wire.

On Sun, 20 Oct 2019 at 01:08, Jerry Gaffke via Groups.Io <jgaffke=
[email protected]> wrote:

Jeff,

The Smith Chart is tricky to explain, your tutorial does a much better job
than most that I have seen.

Don’t you feel that the Smith Chart is *far* away from the original posters
question about things for *beginners*? The original poster suggested
finding the resonate frequency of an antenna.

I did not have the patience to read the article in depth, but a quick skim
read indicated no reference to what the x & y axes are, which is something
I have noticed with several descriptions of the Smith Chart.

But the Smith Chart necessarily introduces complex numbers. Then to get to
admittance, one has to compute the reciprocal of the impedance. At what
skill level are people going to know how to compute the reciprocal of a
complex number?

Jerry

G8WRB.

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

In case someone want to try gnuplot on Windows 10 using WSL, I had success generating a Smith Chart of a choke I'm building. I assume these steps can be adapted to work on Linux with little effort.
1. Install Windows Subsystem for Linux and sudo apt-get install gnuplot (assuming WSL is configured correctly, i.e. sudo apt-get update). I'm using the Ubuntu version.
2. Follow the instructions on the wiki on setting up the Smith Chart files, i.e. and put them in an appropriate folder.
3. Edit plotsmith.p from that folder so it looks like the commands at the bottom of my post. The trick is to write to a file, since WSL doesn't have X Windows support. Don't forget to change the name of the file to match yours.
4. Steps 4-6 are inside WSL: cd to your folder with your files, i.e. cd /mnt/c/Users/(your username)/Documents
5. Run gnuplot
6. Type plotsmith.p (some garbage gets printed to the screen, looks like it is also trying to write the png to the screen)
7. Back in Windows, open the output.png file that was generated, containing a nice Smith Chart.

set terminal png size 1000,1000
load 'smithlabel.p'
set linetype 1 lc rgb "gray60" lw 1 pt 1
set linetype 2 lc rgb "red" lw 2 pt 1
plot 'smithgrid.dat' w l notitle
set output 'output.png'
replot "mydata.s1p" u 2:3 w l title "HF Choke in UHF"

Enjoy,
Roman

I have a NanoVNA with firmware 0.2.3 (build Oct 7 2019). I performed the calibration as advised in the forum and saved CAL data to C0. Everything worked well. However I would like to save a different set of CAL data to C1. I enabled "RESET" followed by calibration and saving data to C0, but when I need to calibrate and save to C1 or other memories, do I need to enable "RESET" again? I tried with reset and not enabling reset but find that i cannot save correct cal data to any location other than C0. I always get wrong results with cal data saved in any location other than C0.

Can someone help me please? Could not find any posts with a similar issue.

Nan
vk2krn

Great idea John!
I guess with some effort (netcat?) raspi could pass nanovna's serial port over wifi to the host PC.

p.s. seems there are free USART1 pins 30,31 on STM for some BT solution, but as you said, it needs too much efforts comparing to rpi zero w.
Zilvis LY2SS