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You can use NanoVNA-Q firmware, it has scanraw command which don't have such
limit, but it returns raw measurements with no calibration corrections.

For 'scan' command, which can return calibrated values,
NanoVNA-Q firmware currently ignores the [points] value, always returning 101,
but 'frequencies' returns the number of points requested.

Using 'scan' command, e.g. in edy555 firmware,
a shell script can combine multiple scans, e.g.:

ch scan
usage: scan {start(Hz)} {stop(Hz)} [points]
ch pause
ch scan 10000 100000 90
ch data 0 > data0.txt
ch data 1 > data1.txt
ch frequencies > freq.txt
ch scan 100100 200100 90
ch data 0 >> data0.txt
ch data 1 >> data1.txt
ch frequencies >> freq.txt
...

Who have used the device to measure Impedance to Common Mode Current vs frequency for bifilar and coax wound ferrite toroid of various materials?

Interested in a step-by-step procedure, which leads tied together, measurements shield to shield, graphic results, and perhaps pictures of test jigs, comments on tolerance, etc.

Thanks!!

Ed McCann
AG6CX

On 23/10/2019 20:21, John Nightingale via Groups.Io wrote:
--------------snip------------------

A little note for new Linux users who find that Rune's application

is not seeing the NanoVNA when it is physically connected: root's
privileges will be required in running the application so that the
application is permitted to make a connection to the NanoVNA. If the
issue is that the application has not been permitted to open a port,
there will be a report to that effect in the console display.

Please don't encourage people to run Linux GUI applications as root. It's a very bad idea.

It's likely that the regular user is not in the dialout group which is easily rectified by entering the following command in a terminal:

sudo usermod -G dialout $USER

You will then need to log out and back in once, after which nanovna-saver should always be run as a regular user.

Cheers,
Barry
G4MKT

Kurt wanted to see some pictures so here they are.

The first picture is the dB logmag of S11 of a 30cm semi rigid cable (medium) and a 1 meter RG58 cable (long), both Open and Short at the end, both from 0.5 MHz till 900MHz
When looking at the polar picture it is obvious the wobble of the logmag at lower frequencies is caused by a shift of the center of the open/short rotation as the lines do not cross (see third polar plot of the long cable 0-300MHz)
In the second picture a 106fF Open C0 correction is applied (as automatically calculated by Octave). This shifts the rotation just enough to remove the crossing of the Open/Short logmag
When I let Octave calculate a cable impedance correction (assuming a small mismatch between the cable impedance and Z0) I get the fourth picture shows almost no wobble. The impedance correction is a shift in the order of +0.025 + 0.5i ohm

For know I am running out of ideas on how to proceed as I do have no good model for the semi rigid cable
Anyone that knows how cables behave in a VNA?

Erik, PD0EK

On Sat, Nov 2, 2019 at 06:50 PM, @arnoh wrote:

at RFPARTS to buy for 3,95$

It looks like cheap Chinese SMA-terminators. If so, they have bad performance.
Try to measure it with multimeter, does it have 50.0 ohm?
Most of all it has high error, something like ±5 ohm.

Mine failed also - a piece of junk. Bought my own online.

On Sat, Nov 2, 2019 at 06:47 PM, hwalker wrote:

On the other hand, its probably unclear to a lot of users how to generate the
equal number of calibration points to correct the raw measurements. Any
suggestions for doing so?

You can do scanraw for O,S,L cal-kit loads and use these results to calculate calibration corrections.
After that just apply these corrections to a scanraw result.

at RFPARTS to buy for 3,95$

Had recently gained bad experiece with cheap SMA-load baught via ebay (aro 1$ a piece), none of them had 50ohms,
so I discarded them, contacted the ebay dealer for replacement, got it, but they were no good either

On Sat, Nov 2, 2019 at 09:28 AM, QRP RX wrote:

You can use NanoVNA-Q firmware, it has scanraw command which don't have such
limit, but it returns raw measurements with no calibration corrections. You're
needs to perform your own calibration procedure.

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

Its great that the scanraw command allows you to return more than 101 measurement points. On the other hand, its probably unclear to a lot of users how to generate the equal number of calibration points to correct the raw measurements. Any suggestions for doing so?

- Herb

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.

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.

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.

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

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 05:34 PM, Maurizio IZ1MDJ wrote:

I think is not possibile to have more than 101 points.

Yes, this is not possible to get more that 101 points with data command. Because firmware has fixed 101 points and you cannot change that.

You can use NanoVNA-Q firmware, it has scanraw command which don't have such limit, but it returns raw measurements with no calibration corrections. You're needs to perform your own calibration procedure.

50 ohm cal load failed

SMA connectors are fragile, and provided load spins in nanoVNA female socket.
Some folks reduce CH0 SMA connector wear by adding male-female adapter.

For frequent recalibration and BNC-equipped DUTs,
I and others buy BNC cal kits, which are IMO more durable and convenient, e.g.:

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.

thanks for the info, I did not think I would be the only one
Thanks Dave 2E0DMB

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.

the load I got happens to have bad contact internally too, reacts when shaking or knocking at the table. Recommend use of better SMA-Loads for calibration.
See RF-Parts or other dealer