• DragonOS notes
• Basic use
• Quick start (demo)
• IQ file formats
• Supported SDR devices
• Examples index

Our thanks to CemaXecuter, author of DragonOS distribution for the time spent testing, experimenting with our tool and ensuring integration into DragonOS. His help is invaluable to us.

On DragonOS distribution, the application executable and basic examples are located in /usr/src/SDR4space.

• Ubuntu x86_64 platforms : https://sourceforge.net/projects/dragonos-focal/
• Raspberry Pi4 platform : https://sourceforge.net/projects/dragonos-pi64/

• Upgrade SDR apps without reinstalling the whole system : https://github.com/alphafox02/focalx_ppa

• To update your DragonOS examples to the latest version :

cd ~
git clone https://github.com/SDR4space/Examples/ SDRVM_latest
cd SDRVM_latest
git checkout DragonOS

• To get the latest PC or RPi VMBASE executable, go to our 'Download and Install page' : http://sdrvm.sdrtechnologies.fr/releases/#download-and-test

A couple of examples are requiring registered license to enable specific modules ( ZMQ support, WebServer, DDC channels). Feel free to write us at [email protected], providing informations on your project to get more informations on licensing.

The main config file settings.js stored at the top root of the project is used as a template config file for the sub-folders.
Update this file according to your setup by adapting variables:

• SDR soapy device name : var sdr_device='driver=plutosdr';

• the default samplerate for this device : var sample_rate=5e6;

• external servers : DB, MQTT, GQRX client...

• observer location for satellite users.

• For most cases the settings.js will be copied to sub-directories at first launch (if missing), BUT only once.
  This will permit later to adjust parameters in each subdirectory, based on a common skeleton.

• Adapt the main `settings.ini' file (sdr_device variable)
• Execute following commands to run a** quick demo based on WBFM (88-108)** spectrum/capture:

cd /usr/src/SDR4space/RX
./sdrvm

Running the ./sdrvm executable with no arguments will start the boot.js script by default (if present)

• Scripts are tested using gnuplot-x11 application.
  gnuplot-qt works also. Maybe !

• For some scripts we are using gnuplot_app variable defined in main settings.js file.
  Please take a minute to check if path is valid (hint: use 'which gnuplot' to get path to gnuplot).

// Define GNUplot path
var gnuplot_app='/usr/bin/gnuplot';

You have choice to get your plots on screen or saved to file. Even both. Edit .gnu file and adapt according your needs.

#GUI output
#set term x11 size 800,500

# output to file
set term png size 1200,500
set output "/tmp/spectrum.png"

#GUI output
set term x11 size 800,500

# output to file
#set term png size 1200,500
#set output "/tmp/spectrum.png"

# output to file
set term png size 1200,500
set output "/tmp/spectrum.png"

plot "/tmp/spectrum.csv" using ($1):2  with lines lt rgb "red"  title 'spectrum'

#GUI output
set term x11 size 1200,500
replot
pause -1

Note : by using the GPU optimized version of our product (usually on Jetson platforms), you need to run sdrvm as sudo !

---------------------------------------------------------------------------------
 SDRVM Version v1.0 - Build : 2021xxxx
 (c) SDR-Technologies SAS - www.sdrtechnologies.fr
---------------------------------------------------------------------------------
Creating Radio Device factory
Disk free space : 7.6 % 
JavaScript SDR/Sat/DSP and more
Usage:
  sdrvm [OPTION...]

  -a, --autoload      Automatic load of license file (default: true)
  -r, --request       Generate a license request for this machine
  -t, --timing        Enable timing for each running task
  -h, --help          Print usage
  -f, --file arg      Script file name/url/archive
  -w, --web           Enable Webserver at boot
  -p, --port          Web server TCP port (overwrite value in 
                      conf/sdrvm.conf)
  -d, --workdir arg   working directory, default is program location 
  -v, --verbose       Verbose mode (default: true)
  -g, --gps arg       set GPS NMEA source port input (ex: /dev/ttyACM0),
                      default baudrate is 9600
  -b, --baudrate arg  GPS Baudrate (default: 9600)
  -s, --service       Runs as system daemon

By default SDRVM will try to open boot.js script in current directory if the script name (-f switch) is NOT specified

A script can be run from different sources :

• .JS file : ./sdrvm -f test.js
• HTTP URL: ./sdrvm -f http://my_server/path/test.js
• From a compressed ZIP file: insert your files/scripts in a compressed file.
  Rename your main script boot.js, then launch it : ./sdrvm -f ./test.zip

SDRVM will handle .cf32, .cs16 and .cs8 extension for filename as IQobject, and .wav as sound file.
That said, we can open a .cf32 file; read it then save it as different name, using CS16 extension.
CF32 --> CS16 conversion is done !

Please see the documentation section for more detailed informations. Check SoapySDR
Use SoapySDR

Most of the script are written using the soapySDR driver, for compatibility reason.

Declaring JSradio object.

var rx = Soapy.makeDevice({'query' : 'driver=rtlsdr' }) ;
var rx = Soapy.makeDevice( {'query' : 'driver=bladerf' });

• Open, save, convert files
• Cut file

• IQ capture
• Spectrum, basic and wide freq. range. Animated spectrums using GNUplot.
• Record a subband of spectrum for a given duration.
• FM and SSB demodulation
• Heatmap over a frequency range. rtl_power like.
• DVB-T monitoring example

DDCBank examples (2 channels and more) are requiring a registered license.

• Basic DDC examples: DDC
• FM recording : single channel , multiple channels (needs license)
• FM receive and transcode voice to text using whisper.cpp

• load TLE
• predictions
• take control over GQRX (doppler and record)

• For mobile operation, capture RF spectrum and log GPS position into a CSV file.