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On Wed, Oct 23, 2019 at 04:28 PM, YT9TP - Pedja wrote:

In meantime I tried NanoVNA-H_AA_20191018.dfu which reports as version 0.2.3-2
and it seems to work ok to. This is good as this is somewhat modern firmware
version.

Could you please check your hardware with this firmware version? (see attachment) It has extended hardware check and if there is some problem with your hardware you will see it on display.

I'm interesting what is root of cause for these reported issues, so I will be glad if you can upload photo or screenshot of your NanoVNA with this firmware. You can take screenshot from NanoVNA with this app:

Hi QRP -

It has extended hardware check and if there is some problem with your hardware
you will see it on display.

Does your 0.4.2 firmware also include this hardware check?


A "hardware OK" confirmation message seems good.

On Tue, Oct 29, 2019 at 01:53 PM, Oristo wrote:

Does your 0.4.2 firmware also include this hardware check?

yes, hardware check for si5351 is included

I flashed the attached firmware and took a screen capture. Please see attached.

Not sure what the PLL means in this firmware but that is the first time seeing it.

Hi KE8CPD -

Not sure what the PLL means in this firmware
but that is the first time seeing it

That is also the first time I have seen it, but it explains your crazy plot.
QRP added a check for those clock chips which cannot do 300MHz.

The workaround is set 'threshold' from USB shell to some value less than 300000000.

On Sat, Nov 2, 2019 at 08:01 AM, KE8CPD wrote:

Not sure what the PLL means in this firmware but that is the first time seeing it.

-------------------------------------------------------------------------------------
QRP's 0.4.2 firmware includes a hardware check for the si5351. It tests if your NanoVNA will operate reliably above 300 MHz. The PLL symbol means that his firmware test has determined that your si5351 may have reliability problems above 300 MHz.

- Herb

On Sat, Nov 2, 2019 at 05:01 PM, KE8CPD wrote:

Not sure what the PLL means in this firmware but that is the first time seeing
it.

This PLL icon means that si5351 failed to setup some frequencies during sweep.
There are two possible reasons:
1) bad configuration settings (it may store invalid frequencies for the sweep)
2) bad quality of si5351 which cannot work at 300 MHz

First try to cleanup configuration settings.
You can do it with "clearconfig 1234" command from PuTTY console.

If it doesn't help and PLL icon is still there, it means that your si5351 chip cannot work at 300 MHz.
You can fix it by reduce threshold frequency below 300 MHz and use saveconfig command to save that change.
It means that working range will be less than normal si5351.
Also, you can replace si5351 with a good one in order to fix that.

Also, you can try to setup START and STOP frequency in the STIMULUS menu, if PLL icon disappears after that, it means that your configuration has invalid frequencies and it's recommended to cleanup configuration settings.

On Sat, Nov 2, 2019 at 09:19 AM, QRP RX wrote:

If it doesn't help and PLL icon is still there, it means that your si5351 chip
cannot work at 300 MHz.
You can fix it by reduce threshold frequency below 300 MHz and use saveconfig
command to save that change.
It means that working range will be less than normal si5351.

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

Does that mean that if threshold frequency is set to 250 MHz then instead of 3 x 300 MHz = 900 MHz the operating limit will be 3 x 250 MHz = 750 MHz?

- Herb

On Sat, Nov 2, 2019 at 06:34 PM, hwalker wrote:

Does that mean that if threshold frequency is set to 250 MHz then instead of 3
x 300 MHz = 900 MHz the operating limit will be 3 x 250 MHz = 750 MHz?

yes

invalid frequencies

FWIW, by setting 'threshold 330000000',
my nanoVNA gets crazy CH0 and CH1 logmag and Smith @ 983140600 Hz
but no PLL icon, perhaps because power-on default scan does not go over 100MHz.

But I think, most of all, this issue is related to some garbage in the settings (bad configuration settings).

Another way to fix bad configuration settings is to cleanup all memory before firmware update. It can be done with ERASE.DFU file.

With NanoVNA-Q v0.4.3 it should not happens, because it has a different magic signature for settings and if there is a bad configuration settings, it should be discarded.

On Sat, Nov 2, 2019 at 06:39 PM, Oristo wrote:

FWIW, by setting 'threshold 330000000',
my nanoVNA gets crazy
but no PLL icon

With thershold more than 300 MHz si5351 will use wrong frequency.
Hardware works ok, so there is no PLL icon, but it uses wrong frequencies, so it won't works properly.
Some invalid thereshold values you may hung your si5351 chip and it will needs power off in order to restore normal functions.

Forcing the SI5351 to above 1200MHZ VCO e.g. above 300MHz fundamental may overheat the SI5351 and permanently damage it.
So you should be EXTREMELY careful when using a threshold command with values above 300MHz.
Its like tuning a car engine. You may get a more performant engine but it also may explode....

Does that mean that if threshold frequency is set to 250 MHz then instead of 3 x 300 MHz = 900 MHz the operating limit will be 3 x 250 MHz = 750 MHz?

Yes and no, it means the nanoVNA will transition to 3/5 harmonics mode at 250MHz till 750MHz and use 5/7 harmonics mode above 750MHz.
All nanoVNA's with modern software can operate till 5 times the threshold value, whatever the threshold value is. The SI5351 may not lock (PLL lock error) or overheat if the threshold is too high.

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK