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I am not a fan of the Si5351. It was intended to be used for digital clock generation for processors and peripherals, not for RF signal generation where reasonable signal quality is needed. Its only attribute is it is cheap, and can do low frequency.

It is the weakest piece of the nanoVNA design. It has a lot of close in spurious outputs, terrible jitter and therefore terrible sideband noise. It is the dominate item limiting dynamic range.

The spec is almost useless and applications notes are difficult to read and understand. The app note AN614 Document change list is laughable with the amount of major errors caught in the document.

Other then that it is a great chip. A technological leap above the transmitter on the Titanic ;

David GM8ARV-
Yes, the ADAFRUIT white page on their SI5351 board I linked to does elude to setting the frequency to 1ppm. I have found and knew it for years, "ZERO BEATING" to WWV doesn't work, because humans can't hear lower than 20-30 cycles depending on age and history with cannon fire.

For those who are not hams FLDIGI is a program for decoding various ham radio digital modes. It uses a computer sound card to display frequency versus time versus intensity (amplitude) in a waterfall display. It has audio frequency readout. Now before someone pipes up - "Well how do you know that's accurate?" We don't .. but what we do know is that WWV and it's carrier is accurate, by superimposing our NanoVNA CW mode signal at 10.0000 or injecting it into the same receiver using nearby antennas.. we can see the WWV carrier and the NanoVNA carrier and see the frequency difference on the waterfall display. In my case it's 110 cycles. WWV is also at 5.0000, 15.0000, 20,0000 and there is also CHU Canada available. So, these days we don't need a capacitor to change, or slug tuning.. Even the SI5351 data sheet specified a crystal in the 25-29 mhz region.. That's because somewhere we deposit a number in a register that aligns the accuracy of the output of the SI5351.. granted to enviromental tolerances, but for a $50 "gizmo" that is in use world wide, that's fantastic.. I started with a US Army Signal Corps BC-221-AF frequency meter, which was the "best you could get" when I got my 1st class Commercial Radio Telephone license in 1971.. Cause a Service Monitor was $1000's. Now go read how to use a BC-221 and we could meet and do better than commercial standards. Back then we'd use a heathkit oscilloscope and display the oscillator "standard" versus the unknown oscillator and produce a Lissajous pattern and using a twiddle stick, get the pattern to look like an "O" and try to stop it from rotating. In the Detroit area we were homebrewing 100.0 cycle PL''s and used a 5:3 Lissajous pattern against 60 cycles. Detroit Edison AC was our frequency standard..

Larry W8LM

Previously posted this to the QCX group. Don't ask why, I'm 85...8^)
...................................................................

Well, I got one of the white plain vanilla NanoVNA-H units from Walmart for $39 and my son is printing an enclosure for me. I've no intention of using it above 60MHz so wasn't concerned about shields and etc. Just something to do some basic ham stuff.

Now, I need some help.

By itself, it seems to be doing what it should do. But...

Attempting to use it with the nonovna-saver software a problem shows up. Scanning for a port produces nothing.
The interconnect cable has a typical USB plug on one end and one of the newer micro USB connectors on the other. The computer does not recognize the VNA as a connected device; it does charge the battery.

I've attached a PDF document with as much info as I could find that might provide some clues?

If anyone can spot something from the PDF info or otherwise that would provide a solution, the info would be greatly appreciated.

Thanks all...
----------------------------------

Update:

I found this in a reply to another message I'd posted...

<If you ordered an older model NanoVNA, with open sides, then you will need to use an OTG cable between the two devices.>

And that's what I have so off to Amazon to order one OTG adapter...

On Sun, Jan 12, 2020 at 10:15 AM, Pete Buxton wrote:

I just opened web app on my Windows 10 computer in Chrome browser, but when I click on Connect, it says "No compatible devices found."
========================================================

Pete,
You're quite right. Other members who have tried to run the web application under Windows have been told that a special driver is required which may or may not mess with some of your other serial port devices. Under Windows there are so many other better applications that the web application is seldom a necessity. For android the devices the web application, or apk if you can get it working, is the only game in town.

If you are determined to get the web application running under windows I remember the driver is the same one I had to use when I installed my SDR dongle.

- Herb

Any ideas why the web app won't connect?

search for "web" here:
/g/nanovna-users/wiki

On Sun, Jan 12, 2020 at 09:42 AM, Roger Need wrote:

There is a bug that in nanosaver. You have to multiply the delay by 10 and enter that into offest delay (under Calibration). So instead of 1690 you have to enter 16900 ps.
=====================================================

Roger,
Try the version Rune released yesterday. That bug had been reported before and I believe Rune was going to fix it in the next release.

- Herb

I just opened web app on my Windows 10 computer in Chrome browser, but when I click on Connect, it says "No compatible devices found."

The NanoVNA splash screen says "GEN111.TAOBAO.COM" and using PuTTY on the serial COM port connects to it and reports:
ch> info
Kernel: 4.0.0
Compiler: GCC 5.4.1 20160919
Architecture: ARMv6-M
Core Variant: Cortex-M0
Port Info: Preemption through NMI
Platform: STM32F072xB Entry Level Medium Density devices
Board: NanoVNA
Build time: Aug 2 2019 - 16:40:01

Any ideas why the web app won't connect? Thanks!

-Peter

/g/nanovna-users/topic/nanovna_saver_and_windows_xp/69405140?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,40,69405140

--
*73, Lucio I0LYL Rome, Italy*

NanoVna_Saver shows only lenght, not delay.

On Sun, Jan 12, 2020 at 04:45 AM, Leif M wrote:

I forgot the sign, + is surely not good. Is 1690ps good for a 32cm or one foot
of coaxial?

There is a bug that in nanosaver. You have to multiply the delay by 10 and enter that into offest delay (under Calibration). So instead of 1690 you have to enter 16900 ps.

Hi everyone, I want to use my nanovna with Windows XP I launch the nanovna-saver program but it gives me an error what procedures can I do to make it go
Roberto iw5bsf

On Sun, Jan 12, 2020 at 08:37 AM, <nanovnauser@...> wrote:

is there a nanovna app that works with ver 6.0.1?
=========================================

Per previous group messages on the subject, below Android version 7.0 the only working solution has been to use the web based application at: but it requires that you are connected to the internet.

- Herb

is there a nanovna app that works with ver 6.0.1?

Hans, DJ7BA, wrote:

I do hope you have SimSmith. Excuse me for a non-finished answer. It's after midnight in Germany.

I do have SimSmith and your experience and mine coincide, Hans. Ideally, we want the maximum available power transfer to occur at the antenna feedpoint. However, in a very low-loss system, we may have a system-wide *near-conjugate match* such that given a standard S-unit is 6 dB, the difference may be undetectable by the human ear.

From: roncraig1@...
[]
It is possible to tweak the synthesizer frequency setting to account for any TCXO tolerance. I don't think this function is written into the firmware and if it is not it might be something that could be put in future firmware. There would be a calibration register in Flash memory for freq offset and the firmware would calculate the required synthesizer setting offset to the desired freq.
===========================================

Whilst the NanoVNA series are not designed as high stability frequency standards, I do agree that having the ability to set a "ppm" value for the master oscillator would be a very useful enhancement.

Copied the suggestion to the NanoVNA-F group.

David GM8ARV
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

PS. also not sure how accurate you can be with zero beating. There may be a demodulator low freq rolloff issue..

Hi Herb and Rune
The S21 phase delay has been fixed OK and the S21 group delay are still correct, thank you indeed to Rune
Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af hwalker
Sendt: 12. januar 2020 00:05
Til: [email protected]
Emne: [nanovna-users] NanoVNA-Saver v0.2.2 #nanovna-saver

Rune has released a "Back From Christmas Update" a few hours ago. See details at: . I'll leave it to Rune to go into any particulars.

- Herb

The nano's have a TCXO module which is not adjustable. The schematic shows a DAC freq trim control line from the uP but I believe all the nano's, beyond perhaps the first ones made, have a TCXO that is not adjustable and their Vcontrol line on the TCXO does not exist. The pad on the TCXO for VC position is just grounded through a zero ohm resistor. You can replace the TCXO with one that does have a Vcontrol but I would not recommend it. The TCXO temp tracking is 0.5 ppm over temp. The initial build tolerance is 1.0 ppm.

The Si5351 has the ability to warp a crystal resonator but since the nano's feeds a clock from the TCXO the warping function will not work.

If you are in fact getting 110 Hz off freq at 10 MHz freq setting you are 11 ppm off freq. This would only be possible if you had a TCXO that did have Vcontrol and it is grounded. You can remove the zero ohm chip resistor to ground on the TCXO Vcontrol pin and put a 0.6v to 3.3vdc variable supply on the pin and see if the freq moves indicating you do have a TCXO with Vcontrol.

The Si5351 has a lot of spurious frequencies and you might be zero beating one of them by mistake.

The nano's should be less then 1 ppm for frequency tolerance.

It is possible to tweak the synthesizer frequency setting to account for any TCXO tolerance. I don't think this function is written into the firmware and if it is not it might be something that could be put in future firmware. There would be a calibration register in Flash memory for freq offset and the firmware would calculate the required synthesizer setting offset to the desired freq.

Thank you so much for the development of the NANO-Saver software. It has
been a blessing in my antenna system work. I do have one request. I
actually like the metric system but many of those that I show the results
have long been English measurement people. In the next iteration of this
software would it be possible to have a choice of metric or English
measurements (Feet vs Meters)? Again, I really appreciate this software and
its functionality.

*Clyde K. Spencer*

Rune,
I'm using firmware 0.4.3Q and the new screen capture module has worked great with all screens I have thrown at it. Thanks for this addition and hope you enjoyed the holidays.

- Herb