frequency_listener

This tool is able to record IQs and perform FM demodulation and save the resulting audio to disk. IQ data is saved as Python pickle data, Audio is saved as Waveform Audio File Format .wav.

Details

This small tool emerges from different needs:

• Dive into IQ and demodulation
• Record my RF tests
• Detect RF activity and be notified about it

Important

Please refer to your juridiction to know if you are allowed to record, save and potentially share IQ or demodulated data.

Prerequisites

An RTLSDR USB dongle.

How to use

Configuration

Edit the configuration file frequency_listener.ini accordingly.

[listener]
duration_s=15 # How long we want to listen

[device_configuration]
center_frequency=105100000 # On which frequency we want to listen
sample_rate=1200000 # Sample rate
frequency_correction_ppm=1 # frequency offset in ppm -- unique for each device

[fm_demodulator_configuration]
enable=true
snr_db=5 # Filter sample by SNR. If computed SNR is under this threshold, sample is discarded and not demodulated
bandwidth=wide # Wide or Narrow band demodulation
max_chunk_size_b=3500000 # If size in bytes is reached, export
max_delay_s=300 # If samples are accumulated until this time window, export
has_ctcss=false # If ctcss should be removed

[exporter_configuration]
enable=true
output_directory=output # Directory to export audio files

How to install

There are many ways to set up an Python environment, here is a suggestion:

$ python -m venv .venv
$ source ./venv/bin/activate
$ python -m pip install -r requirements.txt

How to launch

In the root directoy of the project, call the tool as a python module, passing the configuration file path.

$ python -m frequency_listener -c frequency_listener.ini