开云体育

I remembered and found a USB Bluetooth adapter in my gadget bag. I connected it to the NanoVNA with a USB-OTG cable and usb-micro to usb-C adapter. Scanning for bluetooth devices with my Android v8 phone did not find any devices. I didn't expect the NanoVNA software to have a "host mode" connection and that may be why it didn't work. I was (am) hoping someone might know of a wireless replacement for the USB cable that goes from PC to NanoVNA. But it looks like the chances are very slim. In my case, it's not worth a lot of effort or expense just to save some inconvenience, although if something becomes available it might be very popular.
There may be a way to add such a communication capability to the NanoVNA, but it's probably a major effort and not worthwhile. Unless there turns out to be a lot of other requests for it!

Doug

I do one more thing when I finish the sorting, I stand them up close
together and spray paint the end gently with a color matching the first
number of the mix. 31 is orange, 43 is yellow etc. The marking on the
sides get worn off some times but the paint holds up really well and easy
to physically sort later.

Mel, K6KBE

one should first 'RESTORE 2', then 'RESET'?

Oops, first 'RECALL 2' then 'RESET'?

Anyway, I personally don’t think that it is a good idea to introduce the
Smith Chart to beginners, but others obviously at least one other person
disagrees.

This is a nanoVNA affinity group, and Smith is a default display,
so edy555 presumably considered it appropriate.

nanoVNA shell `data 0` (S11) values can be plotted directly to Smith charts.

Those are among this tool's basic attributes. Other formats,
perhaps more comfortably familiar to some,
are complications to and abstractions from them.

I have had good luck with this home brew fixture using copper clad, N panel mount connectors, BNC adapters and a flexible conductor wire that can be detached on on side using some old cannon connector pins. I did modify my idea several months ago from reading the three articles mentioned in other posts. It definitely works to distinguish ferrite types.

My findings are that type 31 mix will work as great common mode chokes down to 160 meters and up. Type 43 will attenuate common mode from mid HF up.

Spent a few hours going through the door with about 50 mystery 产别补诲蝉/蝉苍补辫-辞苍’蝉.

My method of marking the beads with a grey marker is finding the 3 dB and 6db points on any given bead and writing the frequency next to them.

Run the cal routine with fixture installed. I use the bottom two bnc’s that are pass throughs for the 50 and short load cal.

Gary
KT7AZ

On Sun, 20 Oct 2019 at 09:46, Oristo <ormpoa@...> wrote:

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.

Yes, if measured directly at the antenna, or calibrated there. Beginners
might not know that.

But I find it hard to believe it is the simplest way to show it.

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.

Yes, the Smith Chart is a complicated way of that, with non-linear axes.

The Smith Chart is a plot of the imaginary part of the reflection
coefficient vs the real part of the reflection coefficient, in a nice
linear format.

That gives you a graph which is -1,0 on the left, 0,0 in the middle and
+1,0 on the right. The top is 0,1, the bottom is 0,-1.

Anyway, I personally don’t think that it is a good idea to introduce the
Smith Chart to beginners, but others obviously at least one other person
disagrees.

Dave
--
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 any case to answer the original poster question, reset only affects the
storage register in use and your sweep range etc can all be changed and saved
to that specific register. No changes will occur to other storage registers.

This suggests that, in anticipation of e.g. 'SAVE 2',
one should first 'RESTORE 2', then 'RESET'?

Hi Oristo,

Correct and when the note on calibration was written by Larry, Gary and I, it was based on the "original" first firmware release. Whatever that is called. I assume that part of the cal process has not changed within the instrument itself. If it has, the note should be updated.

If no reset is applied on that ORIGINAL firmware, then the highlighted screen icons would not properly cycle through the cal sequence; namely short, open, load match, thru, isolation. I think the firmware on the instrument for calibration might be improved to avoid this user error. In any case to answer the original poster question, reset only affects the storage register in use and your sweep range etc can all be changed and saved to that specific register. No changes will occur to other storage registers.

Alan

Can you please post a PDF without
links, labels on the axes, so everything is in one file people can read?

If you are unable to at least produce a PDF, I will just mute the topic, as
I feel it is getting nowhere.

On Sun, 20 Oct 2019 at 11:56, yza <yzaVNA@...> wrote:

#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#



--

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

David,

You clearly know your stuff, but sometimes your comments are a bit abrasive.
Here's a rather snarky reply to some of them.

On Sun, Oct 20, 2019 at 12:01 AM, Dr. David Kirkby from Kirkby Microwave Ltd wrote:

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.

See post /g/nanovna-users/message/5223
Jeff was responding to someone who stated "still trying to figure out a Smith Chart"

I did not have the patience to read the article in depth, but a quick skim

Perhaps you should read it before criticizing it?

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

Probably because the x and y axis have no units.

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?

In addition to reading his tutorial, you might also try following the discussion.

From /g/nanovna-users/message/5292

"Perhaps mention at the start what you assume the reader already knows,
and perhaps give pointers of where to learn about it.
I'd say this would be Ohm's law, complex number arithmetic, and complex impedance."

Also post /g/nanovna-users/message/5167
where we are talking specifically about the basic tutorial:

"An appendix with links into other documents with a brief description of what can be found there.
Things like transmission line theory, impedance matching, Smith charts, S parameters."

The discussion in this thread has since expanded a little bit beyond the possibility
of a basic intro document.

Jerry, KE7ER

Somehow my photo of NanoVNA with STM32F303CCT6 and the USB mod uploaded to "files/Hardward Mods" didn't show up there. So I attached my photo below. The PCB was provided by Hugen, since I don't have steady hands to solder such tiny wire and component myself.

A 1.5K reistor was soldered between pin PA12(USB_DP) and VDD so that host PC can recognize the NanoVNA for serial comminication. The C6 decap nearby has a VDD pad near MCU. The PCB is full of flux because Hugen reworked it to replace the MCU to F303, and I did it again to clean up the solder bridge underneath the MCU.

I reaplced the STM32F103C8T6 on a Bluepill board with STM32F303CCT6 for initial porting, before receiving the NanoVNA PCB from Hugen. For debugging, I use ChibiStudio, OpenOCD,
and a Nucleo board as ST-Link v2. Becasue DFU doesn't work at F303 yet, I have to use ST-Link to burn firmware, instead of USB DFU. Maybe a bootloader is needed for F303, like m0nka's mchf SDR transceiver.

For larger LCD, I tried a 3.5" 480x320 LCD with ili9488 controller on my F303 Bluepill. I was able to port to ili9488. But since ili9488 doesn't support RGB656 as ili9341 does, each pixel needs 3 bytes to trasnfer RGB666 or RGB888. And since STM32 doesn't support SPI with 24-bit data, each pixel takes three times of one byte transfer; while ili9341 just neesd to transmit 16-bit data at one time. Besides, the 3.5" LCD has twice the pixels to draw than the original 2.8" 320x240 LCD. Even after some optimization, the result is still dismal. It seems that ili9486, which supports 16-bit per pixel over SPI, would be a better solution than ili9488.

With larger LCD and SRAM, I was hoping to increase the number of sweep points from 101 to 201. Athough I was able to double the sweep points, I could not save the calibration result. Each time I save the calibrated data, it hangs. I think I need to look into the flash.c code.

Ken

Hello Kurt,
that is a wonderful description of what you three did a while go when measuring the performance of ferrite materials. Very cool stuff and because I'm just looking in exactly that topic I have a few questions questions to your fixture. I'm still on a "beginner level" using VNA for measuring ferrite impedances, so sorry for any stupid questiosn.

When you have inserted the ferrite bead and turning the adjustment knob it will contact the SMA F connector at some point. What type of SMA connector did you use? I would imagin that the inner conductor gets damaged pretty fast after using the fixture a few times? Or is that a "special" type of SMA with more robust inner-conductor design ?

Do you know if something similar is commercially available?

Secondly, I like to characterize the ferrits with DC-BIAS current from 0 up to 10 Amps.. That changes ferrite impedance and frequency, depending on saturation of the material.
See
For relatively large ferrite cores it might be easy just adding an additional wire through the inner dimeter, with a DC-current. That way the RF- and DC wires are separated.
But for smaller components like wound-beads (e.g. Fair-Rite 2961666671) I need to "inject" the DC current into the signal line of the VNA. Do you have any experience how to do that best? What kind of RF-filtering / DC-blocking needs to be build ? How is calibration performed then? The additional filtering will definitely change the overall S11 response, but I want to see only the ferrite effect on the Impedance and not any effect of that filter. The intended frequency range is up to 500 MHz for #61 material, but ideally for full span of nanovna up to 1 GHz.

The coordinate system of the Smith Chart is a plot of complex numbers representing
the reflection coefficient. The reflection coefficient is basically a ratio, and thus has no units.

You can read reactance and resistance from the arcs and circles that are drawn as part of the Smith Chart.
The Smith Chart itself is plotted in the complex plane, the coordinate grid is not typically shown on most
Smith Charts but could be either standard issue cartesian coordinates or polar coordinates as fully
described in Jeff's tutorial. That is the whole point of his tutorial. He makes it very clear what and how
stuff is plotted on the Smith Chart. Most Smith Chart tutorials just give the mechanics of how to use it
with a very brief mention that it involves the reflection coefficient.


Here is a brief section of the part where he describes what is being plotted:

Its impedance mismatch (as represented with its Reflection Coefficient) from our target impedance of Zo = 50 ohms calculates to be:
Γ = 0.8 + j0.4
And we can plot its position (using Cartesian coordinates) on the complex plane:

The only thing I might add to the tutorial in this regard would be to state that the reflection coefficient has no units.
Other than that, any suggestions out there on how to improve this aspect of the tutorial?
It is a key concept, and quite confusing.

Jerry, KE7ER


On Sun, Oct 20, 2019 at 01:46 AM, Oristo wrote:

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.

On Sun, Oct 20, 2019 at 12:01 AM, Dr. David Kirkby from Kirkby Microwave Ltd wrote:

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

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.

Hi Dave. I was replying as an aside to Dick’s post-script aside regarding Smith Charts in the thread, here: /g/nanovna-users/message/5216

Best,

- Jeff

If you go through each cal step and save, why can't it simply over-write what
was in the memory in the first place?

My >>guess<< is limited code space and performance:
* Typical use wants correction for each reading
- don't want custom loop for calibration
- don't want special test for calibration to slow that reading loop
- before calibration, set corrections for identity

Hi vk2krn -

"RESET" on touch screen only clears current calibration data, does not affect SAVE 0-4
- unless by some firmware bug[s]
~ configuration data (including calibrations) is liable to accidental damage by firmware bugs.
~ this has caused nanoVNA hangs at power on and other times, loading damaged settings.
~ such hangs doom firmware DFU menu option

Now if I make a fresh calibration for a different frequency range,
(different from C0 which is my default)

That is my default; tweaked nanoVNA has nearly 15 octaves (2**(15) == 8**5),
so 50-400kHz, 400-3200kHz, 3.2-25.6MHz, 25.6-204.8MHz, 204.8-1500MHz

is it correct to just carry out the full cal without selecting "Reset"

No, you should RESET before each cal
(IMO, firmware should change to automatically reset in first cal step)

and saving the new Cal data to a new memory location?

Consider that each of 5 possible stored cal datasets is
101 frequency samples for inline and quadrature phases of reflected and thru.
There is a >>current<< correction dataset (probably in RAM)
that may or may not duplicate one of RESTORE 0-4, depending on current situation.
Firmware has limited storage available; I >>suppose<< that:
- it lacks space and/or code to store fresh samples without applying whatever is current correction
- cal procedure processes fresh samples as if uncorrected
- without RESET, >>double<< processing occurs, with invalid results.

I personally do not understand the need for "reset". If you go through each cal step and save, why can't it simply over-write what was in the memory in the first place? If you save the data with "save" then why do you need to reset anything. What is "reset" actually doing to enable the saving of new cal data?

Perhaps the "reset" is doing something that could better be explained with a different word?

NooElec is more like 1 person not 50! been around for a while. Had a very bad warranty experience with them.
I do not see any advantage in ordering from them.
Authorized give me a break!
Tim

--
Tim W4YN

Hi Starsekr and All,

Another test jig for measuring Ferrite is shown here:

There is also a section describing process for plotting Complex Permeability using SimSmith. The example compares measured complex permeability to Fair-Rite published data.

John KN5L

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

OK, gnuplot Smith chart is slightly smaller by gif than png on my Windows PC,
but gif takes a disturbingly long time to generate, so updated:



.. with a small 'png.p' gnuplot script
for generating "gnuplot.png" from current plot
(remember to rename it so not overwritten by next 'png.p' invocation)
and added Roman's improvements to 'smithlabel.p'