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Hello,

We just uploaded the Agenda of 31st ANAMET Meeting:


and changed [.htaccess]:


Sincerely,

yin&pez@arg

1

Hi Erik
May I add the short should have a pin sitting directly onto a shorting disk which mates with the calibration plane
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af erik@...
Sendt: 21. september 2019 08:30
Til: [email protected]
Emne: Re: [nanovna-users] What options should I look for?

The dummy guide to buying a nanoVNA:

This is the shop of the person that started all this and he delivers good product in excellent packaging.


But if you want to go cheaper these are your options:
Getting the calibration loads is good.
Look for those where the "open" has a hole where the "short" has a pin The cables are also nice as they allow you to have an identical test configuration as many people in this group.
Testing has shown the shielding does not realy make a difference.
Battery is very useful for testing antennas on places where you do not dare to bring a computer.
For the rest, one it arrives, test it and if you are not able to calibrate, request a refund.

On Sat, Sep 21, 2019 at 01:20 AM, <qrp.ddc@...> wrote:

Yes, limiter diode will ruin measurement. There are two issues with diode:
- it add parasitic reactance
- it add non-linear distortions of the signal

100% agree.

There is no simple way to protect RF device with no deterioration of it's
dynamic range.

Seems to be that way.

I had a brief research period last yesterday just to look up how others deal with this issue.

It seems they don't, and simply practice safe procedure.

Spectrum Analysers on the other hand have much higher input levels, and do have some
solutions, but are cannot be used in the case of a network analyser.

I remember my favourite instrument, a Hewlett Packard HP8594 SA having a blown front end and getting a quote for repair.

You could build a aircraft carrier at those prices, whence why the company was always known as High Price ;-)

In the end, I just used a buffer amplifier for general sniffing around as a precaution when it was suitable.

73 de Andy

Hi all,


There are several similar Nanovna clones on the market.
I would like to know what I have (or what perhaps not).

How do I read out my NanoVNA's firmware version?

Is there perhaps a list with info about the different versions?

Is there perhaps also a list with hardware versions?

Anything exhaustive?

Or is there no system perhaps, just chaos, as every producer does what
seems good to him without coordination with other manufacturers?

If so: Did someone try to collect all such info and make it available?


Hans, DJ7BA


---
Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft.

Can you publish or send me your "experimental" firmware? I would like to run some tests on it.

Hi Nick,
thanks for the suggestions! Currently, I have no plans to separate the
plots from the main window, as I see them as a main feature of the
application, and want them there. The code doesn't have anything preventing
it, but I'm not personally going to work on a design that does that, as a
matter of prioritizing what time I have to work on it :-)

File pickers for load/save calibration really should have been in already,
I agree. I'll look at it :-)

And yes, you should definitely get a bigger monitor. ;-)

--
Rune / 5Q5R

The dummy guide to buying a nanoVNA:

This is the shop of the person that started all this and he delivers good product in excellent packaging.


But if you want to go cheaper these are your options:
Getting the calibration loads is good.
Look for those where the "open" has a hole where the "short" has a pin
The cables are also nice as they allow you to have an identical test configuration as many people in this group.
Testing has shown the shielding does not realy make a difference.
Battery is very useful for testing antennas on places where you do not dare to bring a computer.
For the rest, one it arrives, test it and if you are not able to calibrate, request a refund.

There are so many nanovna versions out there and the price varies quite a bit.To get the "best bang for the buck" what should I consider?
1- input shielding2- Calibration loads3- battery4- short m-m cables5- ?????
Thanks for any advice.

Hello,

We just uploaded the current version:



Sincerely,

yin&pez@arg

Forth is a niche language created for writing embedded software on very limited, bare HW. In particular, it is intended to allow you to write and test peripheral control software interactively. The STM32F072CBT6 is 2-4x the memory size of the machine Chuck Moore created it on to control the Kitt Peak radio telescope dishes and many times faster.

With so many people working on variations of the original C code. I'm not sure there is much point to my getting involved with that. Also, I think the use of threads is a major mistake from a software engineering perspective.

I have major issues with bugs and even more with code crashing, ever. Once you allow multiple independent processes to operate in the same address space, unless you use a segmented architecture al la Multics and the Intel x86 and 432, you leave yourself open to one process corrupting another.

In any case, I'm just an old man amusing himself. I've been fooling around comparing the TDR response of my 11801/SD-24 using a bare 3.5 mm connector and the nanoVNA open. There is as much difference between the two channels in both cases as there is between the bare 3.5 mm and the open.

Not quite sure how to interpret it yet. The trace calculated differences are much larger than the display suggests. That's symptomatic of small phase differences, but it's been a long time since I dealt with that and I don't remember yet how you handle it.

Have Fun!
Reg

I tested different SMA connectors with hand connection with no wrench and don't find any noticeable difference.
Probably because NanoVNA works with less than 1 GHz.

Does somebody have any confirmation that using wrenches improves measurement with NanoVNA?

On Fri, Sep 20, 2019 at 03:46 PM, Andy G0FTD wrote:

2 - Wouldn't a diode introduce capacitance across Ch0 ? Or inductive lead
effects at VHF/UHF and ruin any measurements ?

Yes, limiter diode will ruin measurement. There are two issues with diode:
- it add parasitic reactance
- it add non-linear distortions of the signal

There is no simple way to protect RF device with no deterioration of it's dynamic range.

For antenna gain measurement you're needs to place receive antenna at least half wavelength away from transmitting antenna. Otherwise your measurement will be affected by near field of antennas.

Actually the more complete way to calculate minimum distance between antennas is the following:

R = 2 * D^2 / lambda,
where:
R - minimum distance between antennas in meters
D - maximum dimension of your antenna in meters
lambda - wavelength in meters (lambda = 300 / frequency_in_MHz)

If possible place antennas at more longer distance, for example at least on 2-3 lambda. It will reduce near field influence.

Also calibrate NanoVNA through cables which you're using to connect antennas. It will reduce cable influence.

On Fri, 20 Sep 2019 at 13:57, Andy G0FTD via Groups.Io <punkbiscuit=
[email protected]> wrote:

One other thought.

During a discussion yesterday on this group, measurments were taken as to
what the OUTPUT levels were from Ch0.

They were 200mv peak to peak IIRC.

As such, I think I'd want to assume that this would be the maximum level
that any of the ports could handle and would want
to account for.

0.6v (600mv) for a basic diode to start clamping sounds a bit risky to me.

If I'm missing something here then I'm willing to learn ;-)

73 de Andy

The output level of a source is not an indication of the damage threshold.
My HP 8720D can output 10 dBm, but the damage threshold on the test ports
is I believe 30 dBm, so 100x higher.

--

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

I found some finger "wrenches" here:


and a torque limiting "wrench" here:

On Wed, 18 Sep 2019 at 21:39, Rune Broberg <mihtjel@...> wrote:

Hi David,
I don't necessarily intend to break new ground
here, and I haven't yet looked at what's the industry norm for averaged
display.

Do you have suggestions?

--
Rune / 5Q5R

I will have to look for it, but a description of the method used by HP was
posted on the Keysight forum by Dr. Joel Dunsmore. I recall him saying it
is very memory efficient as it does not require one to store all previous
values That was important when early versions of the 8753 were developed,
but far less so now.

The averaging must be done as vectors, not scalers. I will try to find out
how the professionals do this.

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

I've laser-cut some from 3mm acrylic sheet. Black for 0 ohms, green for 50,
clear for open.

John

Hi Jim,
If you could send me the calibration file, I'll have a look at it.

Mihtjel@...

Thanks for taking the time to report the issue!

--
Rune / 5Q5R

Hello Reg,
you can also print them by your own 3D printer.
See

I printed them with PLA in 102% size to fit tight.

73, Rudi DL5Fa

On Thu, Sep 19, 2019 at 02:43 AM, <hugen@...> wrote:

I am discussing with the AA6KL9 to build a new firmware using the
STM32F303CCT6. If all goes well, it can be provided later. To replace the mcu
directly on the current hardware, you need to add a 1.5K resistor to the VCC
on the USBDP Pin. The DFU mode of the STM32F303 requires an external 8M
crystal to use USB, but STM32F072 does not need it, so you need to use SWD to
update the firmware. You need to prepare an ST-Link or DAP-Link.
BTW: The new STM32F072-based NanoVNA firmware already supports TDR.

Thank you!

ok, 8M crystal is normally not a problem for me, but for most nanovna owners F303 is then not real 1:1 replacement. We should probably, if we need more memory, stick on crystal-less USB STM32 (AN4879) , with pullup support, with DFU support (AN3155), LQFP48 package and ChibiOS support. Afaik STM32L433CCT6 should be good replacement, only pullup for USB necessary, and some ADC / clock / I2S changes to code, but it does need newer ChibiOS, which then does not compile with nanovna. Anyway, for myself i will probably solder crystal and use F303 (ADC/clock changes necessary), if i not manage to fix newer ChibiOS compile Errors with STM32L4x series.

tinhead