Configuring file outputs

RTLSDR-Airband can record MP3-compressed audio to local files for archiving purposes.

Syntax

outputs is a list of outputs where the audio stream of a particular channel is to be routed. An output is a group of settings enclosed in braces { }. The number of outputs per channel is unlimited.

outputs: (
  {
    type = "file";
    directory = "/home/pi";
    filename_template = "TOWER";
#   continuous = false;
#   split_on_transmission = false;
#   include_freq = false;
#   append = true;
#   dated_subdirectories = true;
  }
);

Want more outputs? Just repeat the braced section several times and separate individual sections with a comma, like this:

outputs: (
  {
    # ... settings for output 1
  },
  {
    # ... settings for output 2
  }
# , ... more outputs here
);

Remember, do not put a comma after the closing brace of the last output. This is a syntax error.

Explanation of keywords

• type (string, required) - type of this output. Put "file" here.
• directory (string, required) - the directory path where audio files will be stored. It must be created beforehand.
• filename_template (string, required) - the file name prefix. RTLSDR-Airband appends the current date and UTC time to it and creates a new file on top of every hour. A .mp3 suffix is added automatically.
• continuous (boolean, optional) - whether RTLSDR-Airband shall record the audio continuously (true) or skip silence periods when squelch is closed (false). The default is false.
• split_on_transmission (boolean, optional) - if enabled, it caused a new file to be created for every transmission heard on the channel. The default is false. If enabled, then continuous option must be disabled.
• include_freq (boolean, optional) - if enabled, it causes the current channel frequency to be appended to the filename. This is especially useful when operating in scan mode with split_on_transmission feature enabled, as it makes it easy to find out the frequency of each saved transmission. The default is false.
• append (boolean, optional) - if set to true (the default), RTLSDR-Airband will append the recording to the file, if it already exists. When false, the old file will be overwritten.
• dated_subdirectories (boolean, optional) - if set to true (default is false), output files will be placed in dated subdirectories with the format <directory>/YYYY/MM/DD

Marking of recording interruptions

When append option is set to true and RTLSDR-Airband is about to continue writing to an existing file, a series of short beeps will be appended to the file first to indicate the place where discontinuity of the recording has occurred. When continuous option is also set to true, RTLSDR-Airband will append a period of silence of appropriate length to preserve the time scale continuity in the file.

Local timestamps in file names

RTLSDR-Airband puts UTC timestamps in the names of recorded files by default. This can be changed to local time, if desired:

localtime = true;

This is a global option, so put it at the top level of your config (ie. outside of the devices section.

Now you may want to read about configuring other output types for your channels:

• Icecast
• PulseAudio
• UDP audio stream
• Raw I/Q file

or jump straight to:

• Running