Sources¶

A source describes where samples or decoded events come from. The same source model is used by standalone bearer commands and merged receiver configuration.

Get started!

The easiest path to get some data is to start with the VHF or VDL2 subcommands:

datalink vhf --help
datalink vdl2 --help

File and stdin input¶

Raw I/Q files need enough metadata to describe the recording:

datalink vdl2 --format cf32 --center-freq 136500000 --sample-rate 1800000 \
  capture.raw

This is equivalent to the following syntax:

datalink vdl2 file://capture.raw?center_freq=136.5M&sample_rate=1.8M&format=cf32

Tip

datalink can infer some metadata from common capture filenames, WAV metadata, including SDRuno and GQRX-style names.

# Pass GQRX raw files
datalink vdl2 gqrx_20260518_114025_136500000_1800000_fc.raw
# Pass SDRUno file from https://www.sdrplay.com/iq-demo-files/
datalink vhf SDRuno_20200908_152020Z_129535kHz.wav

Set explicit values when inference is ambiguous.

SDR input¶

The standalone vhf, vdl2, and hfdl commands accept RTL-SDR, Airspy, HackRF.

datalink vhf rtlsdr://  # comes with a reasonable set of default values
datalink vdl2 hackrf://  # comes with a reasonable set of default values

SoapySDR is also covered if compiled with the soapy feature.

You may specify more options:

datalink vhf rtlsdr://0?center_freq=131.7M&sample_rate=1.05M&channel=131.725M
datalink vdl2 rtlsdr://0?center_freq=136.85M&sample_rate=1.05M&channel=136.875M,136.975M&gain=auto
datalink vdl2 airspy://0?center_freq=136.85M&sample_rate=6M
datalink hfdl hackrf://0?center_freq=10M&sample_rate=8M

Common parameters are name, center_freq/freq, sample_rate/rate, channel/channels, format/iq_format, gain, bias_tee, amp_enable/rf_amp, rf_gain, lna_gain/if_gain, mixer_gain, and vga_gain/bb_gain.

Tip

If you have enough sample rate to cover VHF and VDL2 with the same SDR device, look at how to handle that with configuration files

Airframes.io websocket source¶

Airframes.io is an event source rather than an I/Q source. Use the standalone command:

datalink airframes

See the public Airframes.io docs for ecosystem background.