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It is a screen protector that prevents the screen from getting scratched during assembly/storage, etc. peel it off if you want to

That green tab might be to disable the battery during shipping??

Sent using




---- On Thu, 26 Sep 2019 17:00:15 -0400 mike watts via Groups.Io <wy6k@...> wrote ----


My unit arrived with a small green plastic tab sticking out the top near the left side.? What is that all about?? Do I remove it?
Mike WY6K


"... somewhere in the distance, there's a tower and a light, broadcastin' the resistance, through the rain and through the night..."

Mike,

It's probably the cheap screen protector that's on it.

Dave-KB1PVH


Sent from my Galaxy S9

On Thu, Sep 26, 2019, 5:00 PM mike watts via Groups.Io <wy6k=
[email protected]> wrote:

My unit arrived with a small green plastic tab sticking out the top near
the left side. What is that all about? Do I remove it?
Mike WY6K


"... somewhere in the distance, there's a tower and a light, broadcastin'
the resistance, through the rain and through the night..."

My unit arrived with a small green plastic tab sticking out the top near the left side.? What is that all about?? Do I remove it?
Mike WY6K


"... somewhere in the distance, there's a tower and a light, broadcastin' the resistance, through the rain and through the night..."

On Thu, Sep 26, 2019 at 09:08 PM, Palo wrote:

Would it be possible to implement some of the features of this project into
NanoVNA?

No, it is impossible, because NanoVNA uses much more slow CPU with much less memory.

EU1KY uses hardware with powerful STM32F746G processor working at 216 MHz with high performance DSP core, 340 kB internal and 8 MB external RAM, 1 MB flash and many other features.

NanoVNA uses very cheap STM32F072CB processor working at 8 MHz with 16 kB RAM and 128 kB flash. There is no resources to implement all these features.

But some of these features may be implemented as separate firmware with dedicated mode for specific feature.

Current NanoVNA TDR implementation is almost useless, because it shows time with 1 nanosecond resolution.

I experimented with different FFT sizes and it looks that 65536 has the best resolution for NanoVNA. It allows to see picoseconds. But it produce a lot of data, it's better to use 32768 points. 16384 also usable, but insufficient resolution becomes noticeable.

This TDR feature just eats precious memory. F072 has too small memory. So, I think it's better to remove TDR function from firmware and replace it with more useful features

One thing I noticed about the screenshot attached to the first post, is the TDR function seems to involve some human interaction. The first peak is a false positive and the cursor at the second peak was the true cable length reflection. There is probably not enough memory to make it a hands off calculation like Rune's NanoVNA Saver performs.

Hello,

Allow us, please, to inform you that we just
uploaded the following two, very rare, references:

[1] Richard H. Hackborn, "An Automatic Network
Analyzer System", Microwave Journal, May 1968, p.47 :


[2] Paul Schmitz, "Vector Measurements of High
Frequency Networks", HP 5958-0387, 5481, 1989, p.3-9 :


which, unfortunately enough, justify fully the writings at [7][3]:
/g/nanovna-users/message/3004

although, some honorable members of this forum
considered them as outrageous allegations of the
insulting kind.

Sincerely,

yin&pez@arg

15

Please be specific. I have no time to study the differences

On Thu, 26 Sep 2019 at 15:16, Dr. David Kirkby <
drkirkby@...> wrote:

Lithium ion batteries can fail with catastrophic consequences.

I know that the switch on the NanoVNA is of appalling quality, but I will
address that by an external switch.

The screen on the first NanoVNA I received was faulty - a problem Hugan
said is common.

A quick look found me this battery



a very reputable manufacturer, around 5 times the stated capacity of those
with the NanoVNA, at a cost of about 50% of the cheapest NanoVNA I have
seen.

This one is just ?0.01 extra, from the same place,

but 3.45 Ah.

Based on someone reporting getting 2 hours from a 450 mA hr battery, that
should last 15 hours, so a good full days work for sure.

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892

Tel 01621-680100 / +44 1621-680100

More time domain samples will not provide better resolution because of the upper frequency limit. However, if the UI allowed picking a peak on the time domain display, one could window that in time, Fourier transform and do a linear fit to the phase to get the delay time and display that.

For peaks which are close together, the Rayleigh criterion set by the maximum frequency is the best you can do. However, the phase fit is most easily done with just a single peak. For an isolated peak the phase resolution and wavelength of the highest frequency measured determines the spatial resolution. I doubt that the velocity factor sufficiently consistent to do better than a few cm.

A basis pursuit will resolve closely spaced reflections, but that's not something that an STM32F series MCU can do.

Off the top of my head, I don't see a way to solve d = a0*exp(j*2*pi*f*t0) + a1*exp(j*2*pi*f*t1) by least squares. Though you might get close enough by estimating a0 & a1 in the time domain and only solving for for t0 and t1.

I wish I had time to work on this more, but other tasks must be attended to.

Have Fun!
Reg

Just the question of the beginner.
Would it be possible to implement some of the features of this project into NanoVNA?



Palo.

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected] group.

File: NanoVNA User Guide - cho45 - reformat-a.pdf

Uploaded By: Larry Rothman

Description:
This is a slightly reformatted and edited version of cho45's excellent (github-based) NanoVNA User Guide. I have made the URL links live as well as added some additional verbiage in order to clarify some content.

You can access this file at the URL:
/g/nanovna-users/files/NanoVNA%20User%20Guide%20-%20cho45%20-%20reformat-a.pdf

Cheers,
The Groups.io Team

Update as promised:
Today, Thursday 26th September 2019 the status of my order from TomTop updated by '17 Track' to "arrived at local Post Office".

I have collected, paid a nominal customs charge (shipping details reflected lower value than purchase + 'Trade sample') and unit was adequately packed (small box with single layer of bubble wrap inside small poly courier packet) with no sign of damage.

Unpacking and initial inspection the legend on front is missing 'Ch 0'as noted by Garry but otherwise all looks correct.

No battery fitted (description on web site makes mention of this) and main board has a 2 pin polarized connector for a battery.

Fitted an old but 'new and unused' Blackberry JM1 battery via direct wiring to rear of connector. Battery is attached to rear panel using double sided tape and although protrudes a couple of mm from bottom, is acceptable.

Powering up the first observation is that both LED's are green (colour is of no consequence) and display, touch input and toggle rocker switch is working.

I have removed the original protective film from the display with intention to cover using suitable size cut from a tablet screen protector.

Charging battery via USB C connector resulted in flashing LED for about 4 min's and then steady as fully charged state achieved.

Accessories included 2 cables and the calibration items (4 in total).

Now to start a new learning curve <smile>.

Any suggestions as to where should start and perhaps a series of 'exercises' (including calibration) so as to have a logical plan to become proficient at using the NanoVNA? Sure would appreciate any guidance from those who have already journeyed down this path - MANY thanks in advance if you can point me in the correct direction.

I am happy that air mail postal delivery (at no extra cost) to South Africa has worked and that I have a seemingly working unit. As to specifics, that is something to report on at a later date.

Wishing all everything of the best learning / using the NanoVNA.

73 Nigel de ZS6RN ex G8DEV

Here's a ham radio application of where a zeroing function would simplify a process:

Let's say you are building a vertical array for 40 meters - two vertical antennas, separated by some distance and with each vertical fed out phase with respect to the other one. You could zero the VNA on one vertical (and call it your 'reference" element) and then, when measuring the phase of the other element, you would be reading the delta between the two, which is what you care about, rather than absolute values.

For only two elements, it's easy enough to subtract one from the other so not a big deal. The software is great as it is!

John AE5X

You flash in the new firmware.
Look in the FILES & WIKI sections for instructions, utilities and files.

As hugen mentioned yesterday, he is thinking of re-integrating (merging?) the larger fonts with his current source code.
The larger fonts were created in order to display Chinese characters.
Hopefully, that will offer more options to all us old, er, more mature folk.

As for the number of traces, install the 4 trace firmware and just turn off 2 of them, if you want.

Regards,
Larry

How do you change to a different version of the firmware?

There are at least two versions of the firmware: one with 2 traces and larger font for an easier to use display or the one with four traces.? You load whichever one you like for your current project.
Mike WY6K


"... somewhere in the distance, there's a tower and a light, broadcastin' the resistance, through the rain and through the night..."

I purchased a NanoVNA from Amazon. I chose the white face version, just for looks. Reading through messages and manuals here, I see descriptions of unit with 4 traces. The one I received only has two traces. Unlike the latest posted manual, there does not appear to be anyway to determine the firmware version. I suspect I may have received a very old unit. I believe the page said "BY HKCNMA".
Anyone provide some guidance?
Thanks
Fred