开云体育

On 17 October 2019 at 23:07 ambaer52@... wrote:


I understand that there is a 4.3 inch version available. Has anyone purchased one? If so, I am in the US. Where is a reliable source to purchase one?

Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937 825 5032
Amateur Radio G8IFF W8IFF and GMRS WRBV701, e-mail nigel@... www

I understand that there is a 4.3 inch version available. Has anyone purchased one? If so, I am in the US. Where is a reliable source to purchase one?

I got one like this -- it has the advantage of skinny profile, display on big screen; the disadvantage of latency, you better move pretty slow to solder smt giblets... The low resolution like 640 is pretty fast, 1280 is pretty slow...

Well, it's actually an itty-bitty 2-port VNA that, within its specs, provides both reflected and through measurements of RF circuits. So, for they typical ham, mostly antennas, and maybe filters. Considering that most 1-port antenna analyzers are ~$300-900, it's pretty amazing. I found that several evenings reading of VNA basics from the Agilent and Aristu documents to be helpful. After all that, tossing away advanced microwave engineering techniques leaves a decent understanding of using a VNA (along with simulation software like mmana and simsmith) in designing and tuning antennas that are {somewhat longer} than 4cm... ;-)
But seriously... For practical applications, set up the screen to to show SWR, resistance, and reactance, and get out your microscope so you can read the screen, and it will become apparent that dipole length controls reactance (+-jX), and height above ground (for a big horizontal dipole) controls resistance...
Then, since it measures phase, there's the whole issue of "where is the reference plane?" and how to calibrate it at the desired plane. Like, you could calibrate it at the end of a 100 feet of coax, then connect that to an antenna, hoist it 60 feet in the air, and measure the actual feed-point impedance, in its environment, from a convenient distance.
Unfortunately, it isn't likely there will be any detailed written procedures for performing specific tasks, as a VNA is a tool that is adapted to the task at hand. But with only consideration of SWR and R+jX, it's much more useful than a simple SWR meter (or basic antenna analyzer), and it will do much beyond that, if you study into the engineering side of VNA measurement a bit. Collect and read the various PDF documents in the files section, and the many posts about calibrating to a reference plane, and it'll all come together. Then you can set it up to do whatever you want.
As a former industrial instrument technician (having calibrated thousands of things), followed by 4 years of writing procedures, I can tell you it isn't easy! as procedures need to be general enough to cover variables in use-cases, but specific enough to be useful. Indeed, as publisher of a rather large how-to web site, I still find users' sending questions of details not adequately covered, even on long and detailed articles I wrote 20 years ago.
73, --kv5r

#54 : [TheLeastVNA] Code with an Application to [NanoVNA]

Hello,

Allow us, please, to inform you that, as we promised it, we just
uploaded the /F/L/O/S/S [TheLeastVNA] at:



The simple contents of lines from 450 and 780 are the
needed statements for any appropriate language, as we
mentioned at:

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

This code is ready to run under the latest version of
BBCWDEMO.EXE downloadable from:



The example input data and their results are for the sample
frequency of f = ~405 MHz of [NanoVNA], and, as it is easily
verified by inspection, they define the RED points for the
measurements of ( s, l, o, g ) in the figures mentioned at:



#51: the full final report 1 with contiguous full online images is here:
/g/nanovna-users/message/5063

as well as those for Z = ( R , X) mentioned at:

30 : our final report 1 - 6 October 2019
/g/nanovna-users/message/4179

that is at:




Sincerely,

gin&pez@arg

54#

Hi Bryan,
thanks - I figured it was something like that, but it's nice to have it
confirmed :-) With your description of how you did your calibration, I'm
sure more people will be using these fields - so I will prioritise getting
the input validation done :-)

--
Rune / 5Q5R

On Thu, 17 Oct 2019 at 23:17, bryburns via Groups.Io <bryburns=
[email protected]> wrote:

On Wed, Oct 16, 2019 at 07:55 AM, Rune Broberg wrote:

I hope this helps you find the issue that caused the crash.

Rune,

I just figured out what is causing the crash I referenced above. If a
user leaves one of the text boxes in the "Calibration settings" area blank,
no number at all, nanoVNA-Saver will immediately crash resulting in the
error:

File "NanoVNASaver\Calibration.py", line 447, in calculate
ValueError: could not convert string to float:

I think this means that you need to check all of those boxes to make sure
they have a valid number before actually trying to convert them to a
floating point number.

--
Bryan, WA5VAH

On Wed, Oct 16, 2019 at 07:55 AM, Rune Broberg wrote:

I hope this helps you find the issue that caused the crash.

Rune,

I just figured out what is causing the crash I referenced above. If a user leaves one of the text boxes in the "Calibration settings" area blank, no number at all, nanoVNA-Saver will immediately crash resulting in the error:

File "NanoVNASaver\Calibration.py", line 447, in calculate
ValueError: could not convert string to float:

I think this means that you need to check all of those boxes to make sure they have a valid number before actually trying to convert them to a floating point number.

--
Bryan, WA5VAH

Jeff got me going, the driver was not installed. Now to get rid of the Smith chart overlay. BTW, the R and j do come up fine on the Saver, Thanks Rune.

Mel, K6KBE

--
Mel, K6KBE

Hello Mel,
I assume your NanoVNA is plugged in, turned on(!), and that you have tried
pressing the rescan button?

Assuming you are running Windows, you may need a driver installed for your
system to recognise the device. I don't know exactly which one, though, but
I'm sure there's someone on this mailing list who will be able to help you
:-) I think there have been occasional cases of the USB connector being
poorly soldered, and the device not showing up for that reason.

I hope you get it to work!
--
Rune / 5Q5R

On Thu, 17 Oct 2019 at 22:23, Mel Farrer, K6KBE <farrermesa@...>
wrote:

Rune, Good Day,

First time user or want to be, hi. 0.1.3 is downloaded and comes up fine,
but does not present a COM port number? What is the best way to approach
this? Thanks,

Mel, K6KBE

On Thu, Oct 17, 2019 at 1:07 PM R D <rdwd3c@...> wrote:

Rune,

What version of the firmware should I install to use with NanoVNA saver?

Rich, WD3C

Hi Erik -

Using the console command "sample" it is possible to measure the pure
reference, refl and thru signal strength.

Can TAPR VNA save those nanoVNA absolute values to files?

Rune, Good Day,

First time user or want to be, hi. 0.1.3 is downloaded and comes up fine,
but does not present a COM port number? What is the best way to approach
this? Thanks,

Mel, K6KBE

KV5R,
that's great to hear! :D I try what I can to make it scaleable, but I don't
personally have a high-DPI monitor (nor serious vision issues - yet), so I
don't have many opportunities to test it. I hope you continue to enjoy it
:-)

--
Rune / 5Q5R

Hi Rich,
it should work with most versions, but I have good experiences with
edy555's 0.2.3 firmware:



There are instabilities and bugs in firmwares older than maybe
mid-September, some of them causing communications issues, so I would
recommend upgrading if your firmware is older than that.

If you (or others) find a firmware that doesn't work with the app, do let
me know. :-)

--
Rune / 5Q5R

Hi Rune,
I am very happy that your software re-scales everything, even if it does cause a little "jitter" of the graphs' sizes... I use so many software tools that do not re-scale, and everything breaks and is un-readable, when old-timers like me need to use on a 32 inch display with 150% zoom + increase screen fonts just to to see. I love programs that scale everything to the display, zoom, DPI, font points, etc.
Lovin' your software!

Rune,

What version of the firmware should I install to use with NanoVNA saver?

Rich, WD3C

On Thu, Oct 17, 2019 at 03:40 PM, <erik@...> wrote:

LCD refresh is suspended during measurement

OK, great. One less thing to test.

What are your thoughts on the transient response of the 3v regulator data sheet I've attached.

Also, I wonder if you could lower the noise by running from 2 Li cells (7.4v) through a linear 5v regulator.
I assume you've done something like that already.

...Larry

Well, has anyone measured the +5 V rail(s) to see how noisy they are? Once that is done the specs for the parts powered by +5 V would need to be looked at to see how noise is too much.

DaveD

Sent from a small flat thingy

On Thu, Oct 17, 2019 at 11:32 AM, <erik@...> wrote:

Next picture shows what happens when you use a clean 5V supply. Much less
noise in the reference signal.

Erik,

This data seems to suggest that if we had better by-pass capacitors on the 5V supply noise in measurements would be reduced. Would you agree?

--
Bryan, WA5VAH

Hi sala nimi,
any examples please?
Thanks.

Have a fun!

N.V.

LCD refresh is suspended during measurement