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I am looking for help to try and fix this problem,
My Linux computer complaint is :

Could not load the Qt platform plugin "xcb" in "" even though it was found.

Indications are this is a library problem with python on Linux .

I have seen others solve this problem but they use developer tools not
available to me.

Still not able to load nanoVNA-saver on any of my Linux computers. (Ubbuntu
XFCE and Mint XFCE ) If you have nanoVNA-saver running on your Linux
computer please tell me what "desktop" version of Linux you are using ?? I
am using XFCE and it does not appear to support nanoVNA-saver.

Thanks in advance,

Nels

--




n_n

If you can lay your hands on some of the old General Radio (GR) connectors,
they would work well. Finding them will be the challenge.

Dave - W?LEV

--

*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

Hi Oristo
It is a difficult task to measure highZ components based on two restrictions.
For the first the DUT used to test the VNA test set up is it really a HighZ with flat response over a large frequency range and for the second part does the test setup destroy the measurement of the well calibrated VNA due to parasitic components.
I have done several reports on the topic where I demonstrated the need to characterize the test adaptor and proven it is possible to measure a 10Kohm resistor pretty accurate. One of the obstacles is that it is forgotten that VNA read outs are as series impedance R+jX and it changed to parallel representation it suddenly is showing fat better results
I see the article you refer to has fought these aspects and not found the clue as the VNA used are probably able to do better but the testjig is "killing" the results.
For a test with the NanoVNA the best way is to use a SMA PCB Edge/bulbhead adaptor and solder the component to centerpin and ground with minimal solder (fringe C) and no leads added. The calibration must be with female kit setting in the NanoVNA-Saver and read out as parallel R and Parallel X. There is one more "snake" as the measurement plane is not the calibration plane for the male SMA to which the female test adaptor is fitted but the QRP firmware has added the feature of positive delay shift so that calibration plane is moved to the rear of the bulkhead/PCB edge adaptor and thus elimination the shunt C and series inductance og said adaptor.
Thinking of finding a way to measure in S21 mode with the NanoVNA is "waste of time" as it requires that both the Ch0 and Ch1 output/input impedance is pure 50 ohm. In the appendix2 of one of the report S21 measurement documented.
to calibrate and measure a DUT like a toroid in shunt mode_2.pdf
Http://www.hamcom.dk/VNWA/How to calibrate and measure a DUT like a toroid correctly the smart way.pdf
Copy paste the URL and watch out it is tough reading so just skim it
Kind regards
Kurt



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Oristo
Sendt: 17. november 2019 15:40
Til: [email protected]
Emne: Re: [nanovna-users] Increasing measurement range (ohms) ?

I wonder how others tackle the problem ?

This discussion answers many "who is on first" questions. Some of
them I had posted on my first post and received some answers too.
I have been reading the mail ever since that first post and have confirmed my suspicion that this forum is users forum, not product developers forum. (Asking other than "how do I do this..." got me labeled as complainer. Very nice. )

I am still working on my original project, however, I have been doing some research into replacing current processor with a device with build in Bluetooth and WI-fi hardware for ANOTHER project.

So this idea of publishing pertinent board documentation which woudl allow to replace the current STM32F072 got my attention.

This post is just initial fact finding.
Currently I am not interested in NanoVNA_WB , as in "WI-Fi" and "Bluetooth" hardware as a money making enterprise, just as a proof of concept of project.
If anybody like to "help out / participate " please reply "Private" since this is NOT user question / post etc.

Vaclav AA7EJ

no, it doesn't work because it requires Android 7+

--
*73, Lucio I0LYL Rome, Italy*

On Sun, Nov 17, 2019 at 06:31 AM, Lucio I?LYL wrote:

nanoVNA on Galaxy S5 neo, Android 6.0.1, otg cable, via browser chrome, @

everything works perfectly without other drivers / apps etc

-----------------------------------------------------------------------------------------------------

Lucio,
If you install the NanoVNA WebApp Android app from the Play Store and use it to connect to the NanoVNA off-line, does it work for you?

- Herb

On Sun, Nov 17, 2019 at 02:40 PM, Oristo wrote:

I have resisted posting anything for the last day or two, since I want to re-evaluate some of my own tests
and thoughts.

But reading the link above, am I to understand that it's worth trying to calibrate with a load other than 50R
then doing some simple back tracking calcs ?

73 de Andy

nanoVNA on Galaxy S5 neo, Android 6.0.1, otg cable, via browser chrome, @
everything works perfectly without other drivers / apps etc
--
*73, Lucio I0LYL Rome, Italy*

As for the Android NanoVNA WebApp (APK off-line version), it now works with
USB-C Android 7.0+ devices that wouldn't work with my other NanoVNA.
NanoVNA-H has the USB-C 1500 ohm resistors installed so I guess if I want
to have my other NanoVNA recognized I'll have to install the resistors manually.

I insert a small USB hub:
so not direct USB-C to USB-C. That hub is not ideal,
because it does not recharge the Android host while it runs NanoVNA WebApp APK

So before purchasing any bad ESN device do a web search and ensure it supports OTG.

FWIW, while Galaxy Nexus nominally supports OTG, the next generation Nexus 4 does not.

I have a VNA that I am working to get sold in kit/assembled form that can
measure 10000+ ohms in the HF in reflection, and can measure 1000+ ohms up
to 600 MHz. I will admit, however, measuring high impedance at VHF/UHF
isnt easy as even tiny amounts of stray capacitance ruin the measurement.
Good fixturing is a must.

In transmission, 10000 ohms is approaching the limit of the S21 measurement
(-50 dB) because of leakage in the SI5351 clock generator. The only way I
know really to fix this would be to use two separate SI5351s to generate
the LO for each port. Not sure if this is worth the effort but certainly
could be done.

It uses the bridge of the EU1KY analyzer which (IHMO) is better designed.
I think the oscillator pins of the SA612s on the NanoVNA are overdriven and
the phase jitter of the IF (which can be considerable when doing a
heterodyne measurement) is not tracked. A Gilbert cell mixer to remain
linear must have its input remain well below 26 mV kT/q (at room
temperature). Also applies common signals to both inputs of the SA612 for
a reason I don't understand, this seems counterproductive.

The design is well shielded and can average over long periods to produce a
relatively high SNR signal from the very low signal input into the SA612.

Hopefully the kit will be available soon....

73,
Dan
KW4TI

For example, if you're transmitting at 3650 kHz and your transmitter has 90W emission at 3650 and 10W at 7300 kHz, your VSWR meter will show you average between 90W at 3650 kHz and 10W at 7300 kHz.

But when you use NanoVNA it will show you VSWR for 3650 kHz with no out-of-band emissions.

if your transmitter has high distortions and out-of-band emission, you will get different VSWR with VSWR meter. Because VSWR meter shows VSWR for all frequencies in the signal. While NanoVNA shows VSWR for specific frequency.

the same, all have 128 kB flash

Hi Herb
My test chamber is just made of parts from the junk box. What you can see is the reverse side of the lid. It has a milled groove along the circumference with same diameter as the inner diameter of the chamber so getting the SMA centerpin on the rod to mate the SMA FF adaptor of the lid is no problem at all. I have a series of test chamber of which I produces the sets so Whitham Reeve and Tom Hagen I the States could measure on the same clamps with same fixture as I did. I attach a zip file with images so you may find inspiration. I also insert a link to the articles we made in thw past.

Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af hwalker
Sendt: 17. november 2019 01:40
Til: [email protected]
Emne: Re: [nanovna-users] NanoVNA-Saver 0.2.0 #Ferrite_Impedance

Kurt Poulsen wrote:

"Just for the fun of it I measured a blue junkbox core as in my closed chamber as seen on the picture. "

--------------------------------------------------------------------------------------------------------------------

Kurt,
The cylindrical test chamber is impressive. I'm sure the test data it yields is more realistic than the one loop procedure used by the OEM's. Is its construction from a test standard or is it per your own design?

So far I am happy with the numbers I am getting from my fixture. They have been repeatable for identically marked split ferrites.

I was thinking about building something similar to your cylindrical test chamber using a round altoids mint tin or a Tenny Tea tin. Still working on a convenient way to disengage the top cover from the inner conductor to change out solid ferrites.

- Herb

See also W0QE youtube channel - - videos #77, #78, #90 he builds VNA cal sets on all sorts of connectors and compares them with lab-grade cal sets.
--kv5r

With so many vendors selling NanoVNA - does any of them specify the flash size - hence actual processor used ?
Or are they all the same ?

Daniel,
Please reference this document, /g/nanovna-users/files/Miscellaneous/NanoVNA%20design%20notes%20by%20edy555/Make%20your%20own%20calibration%20kit%20CALKIT%20for%20calibration.pdf , from this groups "Files" repository.

- Herb

How are the calibration standards that come with the NanoVNA made? I tried to make some out of SMA cable end connectors and it was a miserable failure. It is extremely hard to crimp/solder anything on to the cable except a RG316. Is there a better part to start with?

The band that the primary problem is 40 meters; my xmtr is running on a
conventional power supply, not battery powered.