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New firmware from hugen:

NanoVNA-H version compiled on November 15, 2019

Using the code of nanoVNA-Q of qrp73, the driving of si5351 and aic3204 is more reasonable. By judging that the si5351 locking state is more reasonable than simply setting a delay, it can effectively avoid the noise caused by the unstabilization of si5351.

Unlike the compilation optimization of QRP73 and edy555, inline optimization is not disabled, and the refresh efficiency is better. Due to limited flash space DUMP, SCANRAW, COLOR commands are not available.

Optimized for AA version display.

Hi Ron
If it is the SWR indication build into your radio you are referring to, and your radio has an internal antenna tuner (or I would rather call it a impedance matching network), then the radio is matching to the actual antenna impedance when tuning so the PA stage see a close to 50ohm load impedance. Thus you can newer compare a NanoVNA SWR measurement of the antenna with a SWR indication in the radio display.
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Ron - An Old Ham in Utah
Sendt: 15. november 2019 16:45
Til: [email protected]
Emne: [nanovna-users] SWR...Nano versus Transmitting

This is my first post after lurking since October, so I'm quite new to the Nanovna. The Nanovna measurements of SWR are considerably lower than what I'm seeing when I transmit on-the-air. What does this indicate? Calibration problems, or errors in my other equipment? Any insight would be greatly appreciated. Thanks.
--
Ron, K7UV

These figures for the impedance of CH0, CH1 will vary considerably with frequency.

Jerry

What are you using to measure VSWR while transmitting. If you use a meter
that simply changes scales with no re-normalization for any specific power,
they are quite prone to read improperly when less than full scale power is
sourced from the transmitter. Cross-needle meters do not have this
problem, in general.

Dave - W?LEV

On Fri, Nov 15, 2019 at 3:44 PM Ron - An Old Ham in Utah <k7uv@...>
wrote:

This is my first post after lurking since October, so I'm quite new to the
Nanovna. The Nanovna measurements of SWR are considerably lower than what
I'm seeing when I transmit on-the-air. What does this indicate? Calibration
problems, or errors in my other equipment? Any insight would be greatly
appreciated. Thanks.
--
Ron, K7UV

--

*Dave - W?LEV*
*Just Let Darwin Work*
*Just Think*

On Fri, Nov 15, 2019 at 11:44 AM, QRP RX wrote:

I think you can use 220 Ah battery (220'000 mAh) and it should works ok

It's a shame they all appear to be 12V ;)

On Thu, Nov 14, 2019 at 06:18 PM, Larry Rothman wrote:

Any 18650 cell will be way more than enough for the nano's needs.

Thanks Larry. I'll try and find a "quality" one.

Thanks for the additional explanation, Herb. Sorry if I was too unclear.

It would perhaps be possible for the software to have an 'auto' mode that
started at a low frequency and increased it until the reflection came
conveniently close to the limit of the range for best accuracy. But I don't
really like auto procedures that hide what's really going on : what if you
just wanted to look for partial reflections due to stubs or joints ?

The critical thing is that you obviously felt you should test it at the
working frequency of the system, and I can see why you'd start there. But
as Herb says, what you actually need is to test at a frequency where the
wavelength is comparable with the cable length. Presumably if you tried to
display the results of something more than a wavelength away, you'd get
multiple responses (repeated one wavelength apart).

Rune,
I find myself quite often having to use an external graphics program to add descriptive text to the NanoVNA-Saver chart images I save (See attachment). Is it feasible to add a comment or title box under "Display set-up …" where text can be entered that is placed at the top of the chart as shown in the attachment?

I also inquired on the NanoVNA-F group if there was a corresponding command for NanoVNA's screen capture. BH5HNU responded, "Currently not supported, this is a very useful feature, we consider adding it in the next firmware release." So if you were to implement screen capture in NanoVNA-saver, at least for now it would not work with NanoVNA-F.

- Herb

On Fri, Nov 15, 2019 at 05:36 AM, Barry Jackson wrote:

"If a particular frequency span setting, sweep mode etc. is needed for TDR measurements, should not the software set those modes temporarily when the TDR button is clicked and then revert back to the previous settings on leaving the TDR screen?"
-----------------------------------------------------------------------------------------------
Barry,
Expanding a bit on what Adrian Godwin responded. This is one of those situations where its better to think of frequency like a ham in meters instead of Hz. That helped me to wrap my head around the fact that when measuring meters of cable I needed to change my stop frequency to a value that was equally long in meters for the TDR function to yield good data. If you have firmware installed that has the TDR menu option, you will run into the same thing using the NanoVNA in the field.

Also, as Adrian said, neither the NanoVNA or any software program knows what length of cable you are attempting to measure, so just as you need to manually enter the velocity factor, you may also need to manually change your stop frequency for accurate results.

- Herb

This is my first post after lurking since October, so I'm quite new to the Nanovna. The Nanovna measurements of SWR are considerably lower than what I'm seeing when I transmit on-the-air. What does this indicate? Calibration problems, or errors in my other equipment? Any insight would be greatly appreciated. Thanks.
--
Ron, K7UV

Hello Rune,
thank you for investing in the development of this measurement aplication very very close to the professional.
I draw your attention to the TDR function or indeed the length marker is really good, I think it would be very good that there is in addition to the metric datum Z data and vswr. when you think it's just a matter of reading comfort.
Of course you can always reduce the Z-forearm.
but it lacks a little precision.
can be seen in a future version.
sorry i'm going through an online translator
best 73's eric F4IAB

Hello again,
Thank you for the replies, and thank you Larry particularly. That was just what I needed.
Well, I am not going to claim every single one of the 7000, because some are repetitive,
and I wasn't counting! But it certainly seemed like it.
And I had read that very very useful .pdf file of course. I am glad that I pointed out a need,
and sorry that your finished document now needs an addition. From my days teaching I
really do know that feeling!
Thanks again.
Tony...

In post 1257: /g/nanovna-users/topic/32993803#1257
I calculated the output impedance of CH0 to be 51.53 ohms
and the input impedance of CH1 to be 53.85 ohms.

In the previous post of that thread, Alan got 51.27 ohms for CH0.
There's a bunch of assumptions being made in those calculations,
it would be interesting to measure these figures accurately.

The discussion about correction factors in post 1311
is continued in a different thread with post 1318

Jerry, KE7ER

That's probably a safe way to go, but the -H schematic is still showing the SD103AWS schottky while the STM32F072CBT6 datasheet has 4.0 max for the VBAT pin... not a lot of margin there.

Hi Herb

I have done a lot of such measurements in the past and eliminated the inductance of the wire thru the core.

In your setup I think you get even better result by doing a SOL calibration at the end of the BNC adaptor using the Shorting wire thru the core without the core as short and place a leaded 50 ohm resistor as load and nothing for the open. The you get eliminated the "funny" impedances of the adaptors in the calibration process
To take it a step further read the documents



I use some closed chambers (e.g. tin can for paints with a small SMA female female adaptor in the lid and a shorting pin internally) and in a spread sheet calculate the inductance. In another spreadsheet convert S11 to impedance and subtract the shorting pin inductance
That is the nerd'ed way a bit but the right way to get better data than the manufacturers using a short wire thru the core ?

Kind regards

Kurt



-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af hwalker
Sendt: 15. november 2019 02:49
Til: [email protected]
Emne: Re: [nanovna-users] NanoVNA-Saver 0.2.0



David F4HTQ wrote:



"finally I do not wait for the weekend :)"



-------------------------------------------------------------------------------------



The test method you described seemed simple enough to give it a quick go. Attached is a photo of the test set-up I used. One turn of wire attached to a Banana-BNC adapter and connected to CH0, hopefully similar to your description.



I pulled out the first ferrite core I could find and measured it. The initial curve from 100k-30M looked like junk below 1M and not enough definition at 30 MHz. I changed the range to 1M -100M. The core is definitely not type 43 and pretty broadband in nature. I measured two other cores just like it and their curves overlapped. Found identifying markings on the cores - Laird type 28B2400-000. Found the curves for Laird 28B on-line and have attached them.



The Laird 28B series is definitely broadband but not sure I could have identified my cores from the Laird curves without priori information. The NanoVNA curves for all three cores did match and I suppose I could build up a signature database and use it to sort unknown ferrites.



Thanks for giving me another idea for using the NanoVNA.



- Herb

The TDR range depends on the frequency step and hence the span. Use lower
frequencies to measure long lengths and higher frequencies to measure short
lengths. The software doesn't know in advance what you want to measure.



On Fri, Nov 15, 2019 at 1:36 PM Barry Jackson via Groups.Io <G4MKT=
[email protected]> wrote:

On 12/11/2019 13:35, Rune Broberg wrote:

Earlier today I released NanoVNA-Saver 0.2.0:

Hi Rune,
Thanks for the new version which is performing well.

One issue that puzzles me is regarding TDR.

This seems to depend on other settings like frequency span, but I have
not yet discovered in which way this dependency works.

If for example I have the VNA set to look at an HF antenna VSWR over the
range 3.5 to 7.2MHz and then click the TDR button, the display shows
nothing of use with X values in the 100km range!

After a couple of days fiddling I tried setting the frequency span to 1
to 500MHz and suddenly started to get results that made sense.

If a particular frequency span setting, sweep mode etc. is needed for
TDR measurements, should not the software set those modes temporarily
when the TDR button is clicked and then revert back to the previous
settings on leaving the TDR screen?

Any help appreciated,

Barry
G4MKT

On 12/11/2019 13:35, Rune Broberg wrote:

Earlier today I released NanoVNA-Saver 0.2.0:

Hi Rune,
Thanks for the new version which is performing well.

One issue that puzzles me is regarding TDR.

This seems to depend on other settings like frequency span, but I have not yet discovered in which way this dependency works.

If for example I have the VNA set to look at an HF antenna VSWR over the range 3.5 to 7.2MHz and then click the TDR button, the display shows nothing of use with X values in the 100km range!

After a couple of days fiddling I tried setting the frequency span to 1 to 500MHz and suddenly started to get results that made sense.

If a particular frequency span setting, sweep mode etc. is needed for TDR measurements, should not the software set those modes temporarily when the TDR button is clicked and then revert back to the previous settings on leaving the TDR screen?

Any help appreciated,

Barry
G4MKT

The design of the Nanovna indicates the use of a standard silicon diode - not Schottky? as a number of members suggest.
The reason for this, is to prevent the input to the uP from going above 3.9V, which is the max input.
A fully charged Li battery is around 4.2V so you don't want to drop the voltage by only 0.2v

So - with that said, use a 1N4148 diode and QRP's latest 0.4.3 firmware that allows you to calibrate the battery voltage displayed.
...Larry

A Schottky would be best but any regular (non-zener) would work. The footprint is SOD323 but most people use a PTH style.

NSR0530HT1G (SMT) or SB530 (PTH) for instance.

Hi Tony,
Welcome to the group.? You read all 7000 posts?!? :-)

The NanoVNA is capable of displaying 1:1 SWR graphically so I'm not sure what you are referring to.
You can change the scale on the display to allow you to see finer resolution.
Have you downloaded a copy of the User Guide from the Files section of the forum?
/g/nanovna-users/files/NanoVNA%20User%20Guide-English-reformat-Oct-2-19.pdf
NOTE: I just realised there is no reference in the translated User Guide that describes how to adjust the scale on the display!!? I'll have to add that section.

In any case, select the Display menu and then select Scale.
From there you can set the reference position (defaults to 7, where 0 is at the bottom and 8 is at the top of the display).
Next, adjust the Scale per division.

For SWR, ensure your display Format is set to SWR for CH0 (obviously) and then select a Scale Reference of 0 (bottom division line on the display).?

Then, set your Scale to 0.1 .The bottom of the display will be 1:1 and each division above will increase by 0.1 (ie: 1:1.1, 1:1.2, 1:1.3).
You can also try a Scale of 0.05 for a finer resolution on the display.
I hope this helps (and thanks for the question - I'll have to update the guide now).
...Larry