开云体育

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

Jeff,

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.
I find Python very handy for playing with complex numbers.

I had said:

I'd say it's more useful because it is bounded to a magnitude of 1.0 for passive devices, with points of primary interest at high resolution near the center of the chart.
And that the rather wild curves you get from plotting raw impedance become well behaved circles when plotting the reflection coefficient.

As you know, constant resistance and constant reactance are horizontal and vertical lines, respectively, in the raw impedance plot.
However, the Smith Chart's constant SWR circles would be harder to deal with in the impedance plot.
And since SWR remains constant regardless of the length of series transmission line added, the Smith Chart repeats itself
for every half wavelength of transmission line added by going around that constant SWR circle.

Somebody who makes it through your tutorial might want a pointer to instructions on how to use it.
Here's a possibility:

The companion piece on transmission line theory:

is reasonably good, except it tries to be (somewhat) complete by including a bunch of
higher math (equations with e to the power j times something) on pages 2, 3, and 4
to derive the equations we actually use. Those new to this material should skim that math,
waking up when he gives equations for "voltage reflection coefficient" and "VSWR" on page 3
and the equation for Zin(L) on page 4. Everything after the Zin(L) equation is
well worth thorough study, and uses only secondary school algebra.

Jerry, KE7ER

is this one for real ?

i like the case, first I have seen like it and comes with a USB C to C cable

Nigel/Oristopo,
Thanks for the tips. 'Diginow Serial Terminal' works as Oristopo described for sending shell commands. That means the cabling between the Chromebook and the NanoVNA is correct. The developer doesn't have access to a Chromebook so probably cannot expect any assistance from him in getting the NanoVNA-Web-Client to recognize the NanoVNA.

The Linux Chromium OS distribution looks interesting. I noticed the last Chromebook update offered a new feature to enable Linux, but I wanted to learn more about it before doing so. Using the Chromebook with the NanoVNA seems like a good reason to try it out.

Herb

Hugen has been developing further both the hardware and firmware of the edy555 design.
There are now many clones of what Hugen laid out.

I ordered a nanoVNA from Hugen's friend:

It arrived very quickly via DHL, included battery, cables, and calibration set, I am very pleased.

Here's the post where Hugen mentioned his friend:
/g/nanovna-users/message/658

And a few old threads about where to buy:
/g/nanovna-users/topic/32843998
/g/nanovna-users/topic/32309232

Warranty?
Some might say that they all fail due to a flaky thumbswitch.
But you really don't need to use the thumbswitch much, the touchscreen is fine.
Do you really care about a 6 mo warranty on a $50 device?
I'm fine without, being able to immediately return a defective unit is
about all I could hope for on something like this.

Authorized distributor?
I'd say Hugen's friend, though perhaps there is a way to buy something from edy555 also.
The clones mostly work fine, but there have been some reports of bad workmanship,
no battery (understandable, some shipping services won't take a lithium battery),
no shielding (not clear that it really helps much), some may not work quite as well
at frequencies of 300 mhz and beyond, have older firmware installed,
no callibration kit, no cables, etc ...

Jerry, KE7ER

Probably the easiest solution would be to use a Pi Zero W attached to the VNA and then connect to it remotely with your method of choice (VNC, etc.) With the Zero W you could even use an ad-hoc wifi connection on your phone or tablet while in the field. I look forward to other solutions (like the one mentioned), but if you want to get up and running with the least development time and a moderate cost then this is probably it.

Cheers,
John VA7JBE

Hi Doug

I did it a couple of year ago with a different VNA. I used a wireless USB server. I think the NanoVNA would work this way round as well.

to Operate VNWA2 and VNWA3 Remotely Wired or Wireless.pdf <> copy paste the link into a browser if I does not work

May to day some smart method using the small wonderful Wifi devices with ESP8266 can be developed to do I bidirectional USB link but that is far beyond my skill. I am a hardway hobbyist ?



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af DougVL
Sendt: 20. oktober 2019 01:11
Til: [email protected]
Emne: [nanovna-users] Wireless USB?



I would really like to connect my new NanoVNA to my laptop using a wireless connection. It doesn't seem likely that a bluetooth adapter would work at the VNA end, though. I keep wondering about the wireless mini keyboards that use a USB "dongle" that looks like a bluetooth dongle, but isn't. This would have to be two little devices with USB connectors that talk to each other "automatically" and not need any manual intervention like a mouse click to make the connection. Sort of a non-discriminatory bluetooth that would always accept the first connection attempt.



Does anyone on here know of such a device or system? I've been trying with google but I can't seem to come up with the right search terms. And maybe there is some reason why the NanoVNA wouldn't support such a connection anyway. Maybe one of the firmware developers could find a way to add a wireless connection feature to the system. Giving it a fixed, non-routable IP address to use a USB wifi adapter might be a good way.



Thanks for any help or suggestions!



Doug, K8RFT

Colin, which version of macOS and how did you set up the USB ports?
Tried it here with Catalina but some problem finding the device on the USB…

Dana VE3DS

Jerry,

Thank you very much for your recommendations. They are excellent, and I greatly appreciate your taking the time to make them. (Invariably, when I write a blog post I discover I have left something out. So suggestions such as yours are always welcome.)

I should be able to make revisions in a few days, when I’m back in town.

Thanks again, and best regards,

- Jeff, k6jca

On Sat, 19 Oct 2019 at 15:40, Jeff Anderson <jca1955@...> wrote:

On Sat, Oct 19, 2019 at 06:48 AM, Dick wrote:

ps: still trying to figure out a Smith Chart

Dick, some years ago I wrote up some notes on the Smith Chart (basically
describing where those funny curves come from). It might not be what you
are looking for, but if interested, go here:



- Jeff, k6jca

A bit too technical for the beginner I feel. But that’s just the nature of
a Smith Chart.

It is a very long article, which I didn’t look at too carefully, but you
don’t actually state what are the x & y axes of the Smith Chart, nor the
reason it is more practical to plot an *impedance* on a Smite Chart than on
a normal xy graph.

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

Did you ever figure out how to get the NanoVNA-Web-Client to connect to your Chromebook?

I have not yet tried with the store app; got distracted..

My Samsung Chromebook with either sideloaded apk or web client
also will not connect.

Did you try connecting with Chromebook 'Diginow Serial Terminal' ?
That worked on mine for nanoVNA shell commands..