docker-rtlsdrairband

Docker container to run RTLSDR-Airband alongside Icecast. Builds and runs on arm64. A container is provided for, but not tested, amd64 and arm32v7 (see below).

This container runs an Icecast audio server that RTLSDR-Airband can connect to so that you can use an RTLSDR dongle to listen to Air Traffic Control VHF radio communications, as well some some additional kinds of NFM modulated transmissions (see NFM) via a web browser or audio playback program.

Supported tags and respective Dockerfiles

• latest (master branch, Dockerfile)
• latest_nfm (master branch, Dockerfile.NFM. See NFM below)
• Version and architecture specific tags available

Multi Architecture Support

Currently, this image should pull and run on the following architectures:

• amd64: Linux x86-64
• arm32v7: ARMv7 32-bit (Odroid HC1/HC2/XU4, RPi 2/3)
• arm64: ARMv8 64-bit (RPi 3 and 4 64-bit OSes)

During the container's first run, the rtl_airband binary will be built with optimisations for your detected CPU. In some instances you may need to override the CPU type. This can be done with the RTLSDRAIRBAND_BUILD_PLATFORM environment variable. See below for more detail.

Thanks

Thanks to mikenye for his excellent ADSB docker containers from which I shamelessly copied a lot of the ideas for setting up the docker container, as well as his excellent advice and help in getting this thing working.

Required Hardware

You will need at least one RTLSDR dongle, and if multiple dongles are present on the system the dongle you are using needs to have the serial number set and passed in to the container (see ENV configuration below). Kerberos SDR RTLSDR devices will also work with this container.

Up-and-Running with docker run

docker run \
 -d \
 --rm \
 --name rtlsdr-airband \
 -p 8000:8000 \
 -e RTLSDRAIRBAND_FREQS=123.9 \
 --device-cgroup-rule 'c 189:* rwm' \
 --volume /dev/bus/usb:/dev/bus/usb:ro \
ghcr.io/sdr-enthusiasts/docker-rtlsdrairband:latest_nohealthcheck

You should obviously replace RTLSDRAIRBAND_FREQS with a frequency you wish to monitor.

Up-and-Running with Docker Compose

version: "2.0"

services:
  rtlsdirairband:
    image: ghcr.io/sdr-enthusiasts/docker-rtlsdrairband:latest_nohealthcheck
    tty: true
    container_name: rtlsdrairband
    restart: always
    device_cgroup_rules:
      - 'c 189:* rwm'
    volumes:
      - /dev/bus/usb:/dev/bus/usb:ro
    ports:
      - 8000:8000
    environment:
      - RTLSDRAIRBAND_FREQS=123.9

Ports

Port 8000 is exposed by default in this container. If you want to use another port, set the following ENV variable

• PORT

To the port value you want. In the container startup command, ensure the value you set in the PORT ENV variable is used in place of 8000. For example, using the above docker compose with PORT set to 9000, the port line should look like this

ports:
  - 9000:9000
environment:
  - RTLSDRAIRBAND_FREQS=123.9
  - PORT=9000

Port 8001 is the default port used when ENABLE_PROMETHEUS is set. To use another port, set the PROMETHEUS_PORT env variable to the desired port. If ENABLE_PROMETHEUS is set to any value, Prometheus formatted metrics will be exposed at containerip:PROMETHEUS_PORT.

Volumes

It is possible to mount /run/rtlsdir-airband and provide the container a custom rtlsdir-airband.conf or icecast.xml. Most users will not want to do this. See RTLSDR-Advanced Mode and/or Icecast Advanced Mode for more information.

Environment variables

There are quite a few configuration options this container can accept.

Icecast

Variable	Description	Required	Default
ICECAST_DISABLE	Set to any value to disable icecast server. You will want to do this if you are streaming to an external icecast server such as liveatc or another server you have set up. If this value is set, you should proceed to RTLSDR-Advanced Mode as the default RTLSDR-Airband configuration will not connect to external icecast server	No	Unset
ICECAST_ADMIN_USERNAME	The username used to log in to the admin interface	No	admin
ICECAST_ADMIN_PASSWORD	The password used to log in to the admin interface.	No	rtlsdrairband
ICECAST_ADMIN_EMAIL	Admin email shown in the web interface.	No	test@test.com
ICECAST_LOCATION	Location of server	No	earth
ICECAST_HOSTNAME	The hostname or IP used to reach the icecast server. Used to show correct URLs for the streams on the web interface	No	localhost
ICECAST_MAX_CLIENTS	Maximum listeners	No	100
ICECAST_MAX_SOURCES	Maximum number of clients that can provide a stream to the server	No	4

RTLSDR-Airband

Variable	Description	Required	Default
RTLSDRAIRBAND_BUILD_PLATFORM	On the container's first run, the rtl_airband binary will be built with platform-specific optimisation if this is set. It can be set to rpiv2, generic or native. See RTLSDR-Airband Wiki Compilation build options for more information.	No	Auto-detect
RTLSDRAIRBAND_RADIO_TYPE	Type of dongle that is providing the radio tuning. Right now, only rtlsdr is usable. If you need something else supported, let me know	No	rtlsdr
RTLSDRAIRBAND_GAIN	Gain setting for the RTLSDR dongle	No	25
RTLSDRAIRBAND_CORRECTION	Use this if your dongle has a non-zero frequency tuning error, which requires correcting. Put correction value in ppm here. If the dongle tunes too high, this value shall be positive, negative otherwise.	No	0
RTLSDRAIRBAND_SERIAL	Used to have rtlsdr-airband use the correct dongle if more than one present. Enter the serial of the dongle to be used	No	Unset
RTLSDRAIRBAND_MODE	If you are tuning a single frequency, set multichannel. If you are tuning more than one, set as scan	No	multichannel
RTLSDRAIRBAND_FREQS	If you are setting multichannel for your mode, enter a single frequency. If you are setting mode as scan, enter a comma separated list of frequencies you want to scan. Full formatting of the frequencies can be found here	Yes	Unset
RTLSDRAIRBAND_NAME	The name of your stream	No	Tower
RTLSDRAIRBAND_GENRE	The genre of your stream	No	ATC
RTLSDRAIRBAND_DESCRIPTION	A description of your stream	No	Air traffic feed
RTLSDRAIRBAND_SHOWMETADATA	If not set, the icecast server will receive updated metadata (either frequency or a specific label) of the frequency that is being received, and will show in playback clients. It might be advantageous to disable this because updated metadata will clutter up the icecast server logs. To disable, set to any value. Not applicable to multichannel mode	No	true
RTLSDRAIRBAND_LABELS	If RTLSDRAIRBAND_SHOWMETADATA is set to true, you can set this variable to a comma separated list of labels associated with the frequencies you are listening to. If set, the metadata on the icecast server will be updated to show the label associated with the frequency that is currently being received. If not set, the icecast metadata will be updated with the frequency. * See notes below for more information.	No	unset
RTLSDRAIRBAND_MOUNTPOINT	The custom part of the stream URL. Streams will be accessible at serverip:PORT/RTLSDRAIRBAND_MOUNTPOINT	No	GND.mp3
LOG_SCANNED_ACTIVITY	rtlsdr-airband can output what frequencies it has received traffic on. Set this to any non-blank value to enable	No	Unset
FFT_SIZE	This value controls the general audio quality. A larger value means increased CPU usage. Accepted values are powers of two in the range of 256-8192, inclusive.	No	2048
SAMPLE_RATE	Set the sample rate of the audio stream. See this for more information. Also see notes below.	No	2.56
NFM_MAKE	Set to any value to build the rtl_airband binary with NFM support, see below.	No	Unset
ENABLE_PROMETHEUS	Set to any value to enable rtlsdr-airband generation of Prometheus formatted channel usage statistics	No	Unset
PROMETHEUS_PORT	Port to expose RTLSDR-Airband channel usage statistics on	No	8001

• See the RTSLDR-Airband manual for more information, keeping in mind to not include the parenthesis or leading/trailing spaces.

• Additionally, icecast metadata syncing (with or without labels) may not be in sync with the audio. The RTSLDR-Airband manual explains why.

• Not all RTLSDR dongles will support sample rates above 2.56. If you see a dramatic reduction in reception after increasing sample rate above 2.56, reduce it back down.

Testing

If you want to test and make sure the stream is working, please ensure

• RTLSDRAIRBAND_MODE

Is either unset or set to multichannel

And then add this to your environment variables

• SQUELCH

And set it any non-blank value. That will turn off auto-squelch and you will hear static when you open the stream.

RTLSDIR-Airband Advanced Mode

If you wish to feed multiple icecast servers from the same source RTLSDR dongle, provide the container with more than one RTLSDR dongle, use SoapySDR to access non-RTLSDR dongles, or set up advanced RTLSDR-Airband options that are not configurable via the ENV variables, mount a volume in to the container at:

• /run/rtlsdr-airband

And set the following ENV variable to any value

• RTLSDRAIRBAND_CUSTOMCONFIG

When that value is set, all RTLSDRAIRBAND_* configuration values are ignored and your custom provided rtl_airband.conf will be used.

In the mounted volume, provide a file named rtl_airband.conf with your configuration. See RTLSDR-Airband configuration for details on proper formatting of the file.

SoapySDR support for the following hardware is provided:

• HackRF
• AirSpy & AirSpy HF
• LimeSDR
• BladeRF
• PlutoSDR
• SoapyRemote
• SoapyRTLTCP

Icecast Advanced Mode

Icecast has many advanced options that can be set beyond the provided ENV variables. If you wish to do so, mount a volume at

• /run/rtlsdr-airband

And set the following ENV variable to any value

• ICECAST_CUSTOMCONFIG

When that value is set, all ICECAST_* configuration values are ignored and your custom provided icecast.xml will be used.

In the mounted volume, provide a file named icecast.xml with your configuration. See the icecast documentation for details on proper formatting of the file.

NFM

The primary purpose of this container is to monitor VHF airband communications. However, the underlying software is not limited to strictly VHF communications and AM modulation. By setting the environment variable NFM_MAKE to any value, the rtl_airband binary will be built with NFM support.

This will give rtl_airband the ability to enable NFM modulation and monitor additional radio communications (as I understand it, things like Railroad communications). This is not enabled default because of the additional CPU overhead required (should be marginal, but not negligible if your hardware is constrained).

Accessing the Web Interface

The web interface for the container can be found at containerip:8000 or containerip:port if PORT ENV variable is set.

Feeding Radarbox

First go to the Radarbox website and create a VHF sharing key. The easiest way to feed Radarbox is by using a custom rtl_airband.conf file:

• Map a volume to this container directory: /run/rtlsdr-airband by making sure that the following (or something similar) is added to your docker-compose.yml file:

volumes:
  - /opt/adsb/airband:/run/rtlsdr-airband

• Then save the following text to /opt/adsb/airband/rtl_airband.conf(make sure to update the parameters below to match your configuration and to match your Radarbox credentials):

# Refer to https://github.com/szpajder/RTLSDR-Airband/wiki
# for description of keywords and config syntax.

# Make sure you update the parameters below to match your configuration and your Radarbox credentials

stats_filepath = "/tmp/rtl_airband_stats.txt";
multiple_demod_threads = true;
pidfile = "/var/tmp/rtl_airband.pid";
fft_size=512;
devices: (
{ type = "rtlsdr";
  serial = "replace-this-with-your-airband-sdr-serial-string";
  gain = 49.6;
  correction = 10;
  mode="scan";
  channels: (
  {
    # Put your local air traffic frequencies here. Make a label for each frequency:
    freqs = ( 132.083 , 135.5063 , 135.9545 , 132.2075 , 132.3154 , 133.3569 , 125.9794 , 132.8549 , 132.7553 , 135.9794 , 122.83 , 124.4316 , 134.7055 , 136.4648 );
    labels = ("MUAC Delta High" , "MUAC Delta Medium" , "MUAC Delta Low" , "MUAC Koksy" , "MUAC Lux High" , "MUAC Lux Low" , "MUAC Olno High" , "MUAC Olno Low" , "MUAC Nicky High" , "MUAC Nicky Low" , "MUAC Ruhr High" , "MUAC Ruhr Low" , "MUAC Jever High" , "MUAC Jever Low" );

    outputs: (
    {   # This section defines the details of your feeder to Radarbox. If you don't feed RB, set "disable = true;"
        disable = false;
        type = "icecast";
        server = "audio.rb24.com";
        port = 8000;
        # Put your Radarbox Serial Key and account details below:
        mountpoint = "EXTVHF00xxxx";
        username = "my_radarbox@email.com";
        password = "my_radarbox_password";
        # Give your feeder a descriptive name:
        name = "EuroControl MUAC Multi Freq Scan";
        genre = "ATC";
        send_scan_freq_tags = false;
    }
    ,
    {   # This section defines your local website at port 8000. You can change the mountpoint and name, but
        # please don't change the username/password unless you create a custom Icecast setup:
        disable = false;
        type = "icecast";
        server = "127.0.0.1";
        port = 8000;
        mountpoint = "eurocontrol.mp3";
        username = "source";
        password = "rtlsdrairband";
        name = "EHBK Eurocontrol MUAC";
        genre = "ATC";
        send_scan_freq_tags = true;
     });
  });
});

Logging

• All processes are logged to the container's stdout, and can be viewed with docker logs [-f] container.

Getting Help

You can log an issue on the project's GitHub.