Nanocli is a utility for running measurement sweeps off the original NanoVNA, NanoVNA-Hx (DiSload firmware), or the new SAA2 (NanoVNAv2) from the command line. The sweep results are printed to the terminal in touchstone format.
The utility provides its own error correction. It does not use the onboard calibrations features of either nano. You must calibrate your nano separately to use this utility. The calibration data is stored in a npz file on your computer.
Note, the utility will disturb your nano UI settings (but not on the SAA2). So if you sweep a different range of frequencies using nanocli than what the UI is sweeping, the UI will be affected. That said, nanocli will not upset your nano UI calibrations. They remain as they were.
After calibration, just issue the following on the command line.
$ nanocli
# MHz S MA R 50
0.100000 6.36445e-01 -0.67 2.32551e-05 136.98 0.00000e+00 0.00 0.00000e+00 0.00
2.575000 6.39618e-01 -16.72 5.06521e-05 113.48 0.00000e+00 0.00 0.00000e+00 0.00
5.050000 6.48363e-01 -32.95 3.84420e-05 139.69 0.00000e+00 0.00 0.00000e+00 0.00
7.525000 6.62878e-01 -49.68 3.35834e-05 99.99 0.00000e+00 0.00 0.00000e+00 0.00
10.000000 6.82772e-01 -67.19 4.12503e-05 78.01 0.00000e+00 0.00 0.00000e+00 0.00
If an error gets thrown, like not being able to find the device or ValueError, try again or reset your device. None of the nanos have a perfect USB interface.
First initialize the calibration file, setting the frequency sweep.
$ nanocli --init --start 100e3 --stop 10e6 --points 401
Print details on the calibration file.
$ nanocli --info
start: 0.1 MHz
stop: 10 MHz
points: 401
samples: 3
average: false
cals: <none>
According to the --details option, the calibration file currently has no calibration data. So lets perform the SOLT calibrations.
$ nanocli --open
$ nanocli --short
$ nanocli --load
$ nanocli --thru
After calibration, any change in start, stop, and points will cause new calibration points to be interpolated from the current calibration for the sweep.
Now let's run a sweep.
$ nanocli | head
# MHz S MA R 50
0.100000 6.36109e-01 -0.66 6.35929e-05 136.29 0.00000e+00 0.00 0.00000e+00 0.00
0.124750 6.36282e-01 -0.85 8.50108e-05 150.64 0.00000e+00 0.00 0.00000e+00 0.00
0.149500 6.36318e-01 -1.02 3.74528e-05 175.00 0.00000e+00 0.00 0.00000e+00 0.00
0.174250 6.36327e-01 -1.19 9.57142e-05 122.16 0.00000e+00 0.00 0.00000e+00 0.00
0.199000 6.36398e-01 -1.36 6.56578e-05 168.31 0.00000e+00 0.00 0.00000e+00 0.00
0.223750 6.36308e-01 -1.52 6.65813e-05 122.33 0.00000e+00 0.00 0.00000e+00 0.00
0.248500 6.36368e-01 -1.68 4.90364e-05 115.12 0.00000e+00 0.00 0.00000e+00 0.00
0.273250 6.36432e-01 -1.84 6.34475e-05 -160.78 0.00000e+00 0.00 0.00000e+00 0.00
0.298000 6.36343e-01 -2.01 4.00861e-05 105.09 0.00000e+00 0.00 0.00000e+00 0.00
Write a s1p file to stdout.
$ nanocli --gamma | head
# MHz S MA R 50
0.100000 6.36373e-01 -0.67
0.124750 6.36306e-01 -0.84
0.149500 6.36289e-01 -1.02
0.174250 6.36340e-01 -1.18
0.199000 6.36342e-01 -1.35
0.223750 6.36377e-01 -1.51
0.248500 6.36322e-01 -1.68
0.273250 6.36355e-01 -1.84
0.298000 6.36358e-01 -2.00
Passing the --points option above forces an interpolation of the calibration data to the frequencies of the new sweep. If this option was not given the original 101 frequencies used for calibration would be swept and without any interpolation of the calibration data.
First pip install the required python libraries by going into the top directory of the repo and running:
$ pip install .
Another option is to build an executable file of nanocli. To do this run:
$ sh build.sh
python res/zip.py -s 1 -o nanocli src/* src/*/*
echo '#!/usr/bin/env python3' | cat - nanocli.zip > nanocli
rm nanocli.zip
chmod 755 nanocli
The utility's command line usage is as follows:
$ nanocli --help
usage: nanocli [-h] [--calfile CALFILE] [--start START] [--stop STOP]
[--points POINTS] [--init] [--open] [--short] [--load] [--thru]
[--samples SAMPLES] [--average] [--gamma] [--device DEVICE]
[-i] [-l]
optional arguments:
-h, --help show this help message and exit
--calfile CALFILE calibration file (default: cal.npz)
--start START start frequency (Hz) (default: None)
--stop STOP stop frequency (Hz) (default: None)
--points POINTS frequency points in sweep (default: None)
--init initialize calibration (default: False)
--open open calibration (default: False)
--short short calibration (default: False)
--load load calibration (default: False)
--thru thru calibration (default: False)
--samples SAMPLES samples per frequency (default: None)
--average average samples (default: False)
--gamma output only S11 (default: False)
--device DEVICE tty device name of nanovna to use (default: None)
-i, --info show calibration info (default: False)
-l, --list list available devices (default: False)
The utility uses the (incomplete, one path) 12-term error model to correct sweep measurements. This is the same SOLT calibration method that you use to calibrate the nano from its UI.
To calibrate the nano using the utility, first initialize the calibration file with your frequency sweep. If the calibration file already exists, it will be overwritten. By default the name of the file is cal.npz.
Once intialized the frequency sweep for a given calibration file is fixed. All calibrations will use the same sweep range set in the calibration file. This is because all calibration data within a single calibration file must have measurements for the same set of frequencies.
By default, no interpolation is performed
on your calibration data when making a measurement.
The frequencies for the measurement sweep are taken directly from
the calibration file.
If the range of the frequency sweep is changed on the command line from that given in the calibration file, the calibration data will be interpolated to the new range.
Remember, the frequency range cannot be changed when doing calibration. But when making a measurement sweep it can.
All measurement output from the utility is written to the terminal (using stdout). By default the output will be formatted for a s2p touchstone file. If the --gamma option is passed on the command line the output will be formatted for a s1p touchstone file.
Import this library using import nanocli. The function getvna is provided. After passing it the cal file, the device name, the start frequency, the stop frequency, and the number of frequency points to measure, it returns a function which performs the measurement.
When called this function returns a (freq, data) tuple result. freq is an array of frequencies points. data is a 2xN array of s11 and s21 calibration corrected measurements.
The interface for sweep is as follows. Changing the range for the frequency sweep by passing values for start, stop or points will force an interpolation of the calibration data.
Setting the filename option will save the results to this file. The function will then return the name of this file. The file extension must be either 's1p' or 's2p'.
sweep = getvna(device=None, calname='cal')
sweep(start=None, stop=None, points=None, filename=None)For example:
$ python3 -c 'from nanocli import getvna; f,d = getvna()(start=3e6, stop=6e6); print(d)' | head
[[ 6.03945344e-01-2.13709216e-01j -4.64940000e-05+7.38160000e-05j]
[ 6.03728192e-01-2.14155776e-01j -3.82350000e-05+3.75260000e-05j]
[ 6.03539712e-01-2.14678176e-01j 9.33400000e-06+6.19160000e-05j]
[ 6.03384448e-01-2.15204416e-01j -1.79890000e-05+3.35190000e-05j]
[ 6.03226368e-01-2.15712160e-01j -2.77610000e-05+5.45100000e-05j]
[ 6.03012032e-01-2.16203120e-01j -2.74510000e-05+4.38000000e-05j]
[ 6.02889792e-01-2.16796880e-01j 2.18270000e-05+4.54730000e-05j]
[ 6.02720576e-01-2.17342912e-01j 3.94900000e-06+7.72860000e-05j]
[ 6.02566464e-01-2.17785216e-01j -1.45040000e-05+4.35450000e-05j]
[ 6.02368448e-01-2.18366880e-01j -1.37610000e-05+5.90930000e-05j]
I needed the ability to perform a calibrated measurement from the terminal or from a Jupyter Notebook, for example. The original nano had this ability through its (USB) serial interface and its "data" command. However the new SAA2 does not. It uses a special binary protocol. Its measurements over the USB interface are also uncalibrated unlike the original nano. Lastly and probably, most importantly, with the SSA2 you cannot control its UI over USB. So no more computer remote control visual operation of the device like I was able to do with the original nanovna. As a result this utility is intended to unify the two nanos to satisfy my above need and do my remote control in Jupyter instead.
In order to perform a measurement sweep on the original nano, the utility first turns calibration off on the device. Once the measurement is made, the utility will turn calibration back on. For the SAA2 nano, since its USB connection is always uncorrected its UI and calibration is unaffected.
For the NanoVNA, only versions 0.7.1 and higher of the firmware are supported.
See the papers on Network Analyzer Error Models and Calibration Methods by Doug Rytting.
