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SO-239 connectors have terrible SWR about 1.2. If you don't use more than 100W power, it's better to use SMA. For more power it's better to use N connectors

Yes, I've heard someone else mention that. I can't quite think what causes
it, *assuming* the firmware didn't change the format of the commands used.
I currently just have the one NanoVNA, and as I need to use it for
development, I have been a bit reluctant to flash experimental firmware on
it. I may have to try :-)

--
Rune / 5Q5R

On Sat, 14 Sep 2019, 11:13 David J Taylor via Groups.Io, <gm8arv=
[email protected]> wrote:

From: Rune Broberg

It's Friday, and that apparently means NanoVNA-Saver 0.0.9:

=======================

Rune,

Trying with the new 10k-1500M firmware. If the start frequency is set to
lower than 50000 (I tried 10000 and 40000) the program shows an hourglass
timer and then simply aborts, taking the command script with it.

Difficult to keep up, I appreciate!

Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

From: Rune Broberg

It's Friday, and that apparently means NanoVNA-Saver 0.0.9:

=======================

Rune,

Trying with the new 10k-1500M firmware. If the start frequency is set to lower than 50000 (I tried 10000 and 40000) the program shows an hourglass timer and then simply aborts, taking the command script with it.

Difficult to keep up, I appreciate!

Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Hi David,
I have seen situations where the NanoVNA had not changed frequency after
being asked to do so in the about 500ms I've arbitrarily decided to give
it. In this case, it would repeat the data it had prior to changing
frequency, but still send the new frequencies (as some more time would have
passed)

I will try to put some handling of this problem in the next version, which
might just be increasing the delay a little.

--
Rune / 5Q5R


On Sat, 14 Sep 2019, 10:56 David J Taylor via Groups.Io, <gm8arv=
[email protected]> wrote:

From: DMR

RFpro, Firmware 10KHz-1500MHz.
By default, when turned on, 50KHz-900MHz.
Expand the boundaries in the frequency setting menu.
Added dfu menu item, now it is not necessary to close the jumper with
tweezers. This assembly is based on source codes EDY555 & Hugen. At one's
own risk. Work with other software is not guaranteed.
The display measures the reference capacitance 15nf, Port S11.
================================

Thanks for the note. I tried this firmware and indeed it does provide an
indication of resonance up to 1.5 GHz. I note two oddities:

- when first switching on, the S11 scaling is 1 dB/division, and I'm
unsure
how to change this. Somehow, selecting the yellow trace format it went
back
to a more useful 10 dB/division, but on switching the device back on it
returned to 1 dB. It may be that switching the trace between logmag and
phase, and back again, restores the 10 dB scaling.

- using the nanovna-saver-v0.0.9, after changing the frequencies and
running
the sweep, the old sweep remained, but the frequencies had changed.
Running
the sweep a second time resulted in a new sweep matching the frequency
scale. This could have just been finger trouble on my part.

On issue I do still see is that while the S11 plots are sensible with an
antenna connected, with an open ch0 and ch1, the yellow S11 plot shows
from -7 dB to -10 dB across the 0-900 MHz frequency range.

Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

From: DMR

RFpro, Firmware 10KHz-1500MHz.
By default, when turned on, 50KHz-900MHz.
Expand the boundaries in the frequency setting menu.
Added dfu menu item, now it is not necessary to close the jumper with tweezers. This assembly is based on source codes EDY555 & Hugen. At one's own risk. Work with other software is not guaranteed.
The display measures the reference capacitance 15nf, Port S11.
================================

Thanks for the note. I tried this firmware and indeed it does provide an indication of resonance up to 1.5 GHz. I note two oddities:

- when first switching on, the S11 scaling is 1 dB/division, and I'm unsure how to change this. Somehow, selecting the yellow trace format it went back to a more useful 10 dB/division, but on switching the device back on it returned to 1 dB. It may be that switching the trace between logmag and phase, and back again, restores the 10 dB scaling.

- using the nanovna-saver-v0.0.9, after changing the frequencies and running the sweep, the old sweep remained, but the frequencies had changed. Running the sweep a second time resulted in a new sweep matching the frequency scale. This could have just been finger trouble on my part.

On issue I do still see is that while the S11 plots are sensible with an antenna connected, with an open ch0 and ch1, the yellow S11 plot shows from -7 dB to -10 dB across the 0-900 MHz frequency range.

Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Hello Rudi,
when you start the program, it initially uses only the device calibration -
that is, from the application point of view, it displays uncalibrated
readings.

I am sorry to see the crash you experienced - if you would send me the
calibration file you have saved (either on the list, or direct to
mihtjel@... ) I will try to reproduce and fix the problem as quickly
as possible.

Thank you for trying out the software, and for taking the time to report
the problems you find!
--
Rune / 5Q5R

This is a firmware based on the original Edy555 firmware with some small changes
- Upper frequency limit is increased to 1500MHz. Be aware accuracy decreases rapidly above 900MHz
- A "scan" console command is added to allow arbitrary sweeps with arbitrary number of points
- The stack sizes of the two main threads have been adjusted for increased robustness.(thanks to david mugridge )

/g/nanovna-users/files/NanoVNA%20PC%20Software/TAPR%20VNA/NanoVNA%20with%20scan%20and%201500MHz.zip

Hi David,
If you suffix a number entered with k or M, it will be interpreted as kHz
or MHz. :-)

The other set of fields automatically updated will be in Hz, though.

--
Rune / 5Q5R

Hi George,
thank you very much for evaluating my measurements.
Attached is a picture of the "Standards" that I made. For my opinion these are very reliable. You can reconnect them and you will still get the exact same result.

Best regards
Norbert

Hi

I've compiled and flashed a pull request that was made to the master branch a few days ago for Time Domain functions on the device.

The commit is still open on Github .

It reads :

Although it may not be perfect, I tried to see the value in the time domain. The menu is based on the HP8753 (I don't know the actual machine, but I refer to the manual)

Implementation policy

Ifft of 101 measured at 128point. However, after calculation, it is truncated to 101 points and returned to measured.
The graph drawing itself remains the existing logic (only domain conversion)
Reusing spi_buffer for temporary computation.
Known but not addressed issues

Since measured is rewritten, ifft is taken via USB, the iffted one is taken
(I think that storing measured by domain is impossible in memory)
When sweep is broken by ui operation, the graph is distorted because measured is ifft with a halfway value (it seems to be devised)

Please find the dfu file attached, I've changed the accuracy of the distance measurement so that it shows more precision "%.1f" vs "%.3f".

Happy testing

Regards
Ohan
ZS1SCI

Ps. a guide to ubuntu compilation for the masses can be found here

Rune,
Thanks for the update it makes the VNA more useful every day.

Would it be possible to enter the start and stop frequencies as Megahertz instead of Hz.
Its a lot of zeros to enter.

Perhaps we could have a drop down box or radio button so as to enter MHz, KHz or Hz.
It would save the chance of entering too many or not enough 0's

David

Hello Rune,

Thank you very much for the lot of useful extensions in version 0.0.9.

I have tried the Calibration and have a problem with it:

1. When I start the program nanoVNA-saver.py which calibration is used, or none?

2. If I load my saved calibration file and start a sweep I get a divide by 0 error:
Settings: /Volumes/DAT/Users/rudi/.config/NanoVNASaver/NanoVNASaver.ini
Traceback (most recent call last):
File "/Volumes/DAT/HDA8/INSTALL/Develop/Afu/NanoVNA/nanovna-saver-009/NanoVNASaver/SweepWorker.py", line 87, in run
self.saveData(frequencies, values, values12)
File "/Volumes/DAT/HDA8/INSTALL/Develop/Afu/NanoVNA/nanovna-saver-009/NanoVNASaver/SweepWorker.py", line 150, in saveData
re21, im21 = self.app.calibration.correct21(re21, im21, freq)
File "/Volumes/DAT/HDA8/INSTALL/Develop/Afu/NanoVNA/nanovna-saver-009/NanoVNASaver/Calibration.py", line 375, in correct21
s21 = (s21m - self.e30[index]) / self.e10e32[index]
ZeroDivisionError: complex division by zero
Abort trap: 6

How can I avoid it?

73, Rudi

This is a follow up to my earlier post. The results of the measurements the nanoVNA gave me on the previous two amplifiers I tested gave me the confidence to check a third preamp bought "as is". It is a Mini-Circuits preamp with a handwritten note saying, "27 dB gain, 1-1000 MHz".

Test procedure used:
1. Turn the amplifiers on to allow them to warm up and guard against turn on transients damaging anything during testing.
2. Turn on the nanoVNA, set the display to CH1/LOGMAG only, 10 dB per DIV, reference position at 4 divisions to be able to see 27 dB gain.
3. Connect a 20 dB attenuator to CH1 and a 6 dB attenuator to CH0 to closely match the expected 27 dB gain of the preamp.
4. Connect attenuators together using a cable. The nanoVNA should be showing a 26 dB loss over the frequency range. If not your attenuators are not flat
5. Change to the calibrate menu and select "reset" and then perform a "through" calibration. The new reference should be 0 dB at 4 divisions.
6. Connect the output of the 6 dB attenuator to the input of the amplifier and output of the amplifier to the 20 dB attenuator.
7. Read the amplifier gain in dB directly on the nanoVNA using the marker display.

Results:
The nanoVNA showed a gain of 27.5 dB, +/- 1 dB across the measurement range of 1-900MHz, verifying the preamp was operational.

My close friend teaches electronics at a local school and received permission to order 15 nanoVNA's for use in his class this semester. He already has a couple on hand and he said his students are drawing lots to use them. He's excited that his students are getting hands on experience with VNA concepts, exposure to Python scripts, and upgrading firmware. I wish I had something like this when I was a student. Actually I wish I had one of these before I spent money on equipment sitting in the corner that didn't live up to its billing.

It is clear that outstanding characteristics at frequencies above 1 GHz cannot be obtained, but this allows you to quite well see the resonance of the antenna at these frequencies, and adjust it. For this, this firmware was compiled.

WOW!, I am so impressed that the range can be extended that far without hardware modification. Once I build up the courage to update the firmware, I will at long last be able to check my homemade 1090 MHz "cantenna" to see if I cut the active element to the correct length. So for me, 1500 MHz is more than I could have ever dreamed of in a device this inexpensive.

But all of this discussion about the 300 MHz overtones used to reach these new heights does beg the question...is the ultimate ceiling for the upper frequency on the nanoVNA imposed by the physical layout on the board, the chips themselves, or is it due to the diminishing intensity of the overtones that comprise the square wave? And what if I could accept a measly dynamic range of say, just 10 dB just to check the resonance point of a tiny antenna...I wonder what the ultimate frequency limit might be?

Thanks Rune,
that works!

73s Holger, DF6DBF

On Fri, Sep 13, 2019 at 10:11 AM, DMR wrote:

RFpro, Firmware 10KHz-1500MHz.
By default, when turned on, 50KHz-900MHz.
Expand the boundaries in the frequency setting menu.
Added dfu menu item, now it is not necessary to close the jumper with
tweezers. This assembly is based on source codes EDY555 & Hugen. At one's own
risk. Work with other software is not guaranteed.
The display measures the reference capacitance 15nf, Port S11.

Can you tell me if the original shell commands, used over the serial com port, are intact?
If so, It'll be relatively easy to modify software for new ranges.
If there are any new shell commands in addition to the original commands please let me know that too.
Thanks.

Eric,
When the nanoVNA was first released I believe there was a 1050 MHz DFU that was pulled from the repository pretty quickly. Do you know why that release didn't make it, while the 1500 MHz DFU seems to be gaining traction?

Hold your horses
Above 900MHz the 5th overtone is used so at 1500MHz the actual port 0 output is a square wave of 300MHz and at port 1 this is mixed with the 7th overtone of a 214286428Hz to produce the 5000Hz input signal for the DSP stage
This works because a VNA controls both the output signal and the mixer LO.
For using as a SA please read my post on using the nanoVNA as spectrum analyzer.

DMR
Thanks! I just recalibrated it. And did run some tests. Obviously no hardware modifciations (change series - C's) have to be done.