RTL-SDR

The RTL2832U & R820T is a software defined radio/tuner USB dongle capable of receiving 24 - 1766 MHz radio signals, including DVB-T.

You can use it with e.g. a Raspberry Pi or any other Debian based Linux to listen to FM radio.

Installation
Building from sources is not necessary any more... apt-get install rtl-sdr

Configure amixer
Audiomixer has different controls depending on the operating system version and configuration:

Version 1
Audio controls: amixer controls

numid=3,iface=MIXER,name='PCM Playback Route' numid=2,iface=MIXER,name='PCM Playback Switch' numid=1,iface=MIXER,name='PCM Playback Volume'

Set jack (analog) output: amixer cset numid=3 1 Set HDMI output: amixer cset numid=3 2

Set audio volume: amixer sset "PCM" 90%

Version 2
Audio controls: amixer controls

numid=4,iface=MIXER,name='Master Playback Switch' numid=3,iface=MIXER,name='Master Playback Volume' numid=2,iface=MIXER,name='Capture Switch' numid=1,iface=MIXER,name='Capture Volume' Enable audio: amixer cset numid=4 1 Set volume at 76% amixer cset numid=3 50000 Verify: amixer

Simple mixer control 'Master',0 Capabilities: pvolume pswitch pswitch-joined Playback channels: Front Left - Front Right Limits: Playback 0 - 65536 Mono: Front Left: Playback 50020 [76%] [on] Front Right: Playback 50020 [76%] [on]

Test aplay
You should hear a kitten miaw... aplay /usr/share/scratch/Media/Sounds/Animal/Kitten.wav

Listen to FM Radio
Tune into an FM radio station: rtl_fm -f 91.7e6 -s 200000 -r 48000 |aplay -r 48000 -f S16_LE

Other applications

 * ADSB tracking
 * gqrx