Radio Automation Systems

Rivendell

www.rivendellaudio.org/

Version 2.4.0 is available as source.

It’s a “complete radio broadcast automation solution, with facilities for the acquisition, management, scheduling and playout of audio content.” Looking through the history, it’s been developed for feeding actual radio (not internet radio) transmitters, but the output can now be routed through JACK for streaming.

Airtime (formerly known as Campcaster)

www.sourcefabric.org/en/products/airtim.../

Version 1.8.2 available as source, builds on Ubuntu 10.04 and up. Precompiled packages are available for Debian and Ubuntu.

Similar to above, but with a slightly simpler signal architecture and a web-based interface that most people will probably find easier to use. The code is GPLed and the company sells support. The version numbering (>1) is a bit confusing, as their literature says the product is “not 100% ready for production” so consider it a beta.

Video of presentation and slides from Linux Audio Conference 2011

R4DIT

Version 1.0 beta and previous RC available at www.radit.org/foro/viewforum.php?f=17 for both win32 and linux (.dpkg pkgs)

simple to use rather complete software…

Video of how-to create a radio station using linux (SPA)

DJ software

xwax

www.xwax.co.uk/ (version 1.1 announced on 29th Jan 2012)

This is a free-software implementation of “vinyl emulation”, which means controlling your digital playback (mp3, ogg, flac, whatever) from the computer, using an actual real vinyl record on an actual real turntable as the controller. It works by reading time-codes from the vinyl, into your PC, which interprets them as control signals for the media player.

The reason for using this sort of thing is if you’re into beat-mixing, scratching and all those other advanced techniques that feel best with a real turntable.

mixxx

www.mixxx.org/

Similar to the xwax, initially developed for people who are happy using “turntable controllers” rather than actually placing a needle on a record, but more recently (version 1.10) including vinyl control. Also works great as an advanced audio player without a dedicated hardware controller, as in this example.

idjc (Internet DJ Console)

idjc.sourceforge.net

Internet DJ Console is in ubuntu and debian repositories and can be built from source for other systems. It is a network client designed for producing an icecast/shoutcast stream. It’s fully jack-compatible, so all your signal processing can be done outboard, and there are instructions for how to integrate VOIP services (e.g. skype) for phone-ins. There’s an easy to use jingle deck that you can populate with whatever snippets or samples you like. You could do all of that using other software, but IDJC presents a friendly interface with lots of key bindings making this kind of work easier for the less geeky.

RF modulation

‘Internet radio’ is an output medium with broad geographical reach and low cost of entry. However, many of us are still interested in broadcasting actual radio, i.e. outputting radio frequencies from a transmitter. This is the kind of software you’ll need for that kind of project:

GNU Radio

gnuradio.org/redmine/wiki/gnuradio

This one is probably of more interest to RF hackers than people who want to get something working quickly. The main thrust of the project seems to be driving a RF DAC using a wide range of different encoding schemes, so you can plug your output into the RF amplifier rather than having to spend money on hardware modulators. Definitely worth a look if you’re setting up a real RF transmitter and want to control the stack.

RF demodulation

Most people have an old transistor radio set knocking around somewhere, but maybe you want to use your linux box to process RF back into audio? Or maybe you have some other reason to be interested in decoding RF? These projects may be of some help:

linrad

www.sm5bsz.com/linuxdsp/linrad.htm

Full-featured multi-platform software-defined radio with support for lots of different hardware. Lots of features, including the ability to divide computationally intensive tasks between networked processors.

quisk

james.ahlstrom.name/quisk/

Another feature-rich SDR with a nice GUI, can also control transmission gear.

lysdr

github.com/gordonjcp/lysdr/

For use on systems with less processing power, a lightweight software tuner for FM signals.

lo

gitorious.org/carmen/lo

Adds amplitude modulation (AM) support to above.

Synchronisation

libltc

x42.github.com/libltc/

POSIX-C Library for handling Linear/Logitudinal Time Code (LTC): enables synchronous control of transports for recording, playback and editing – useful for radio hackers with complex sync requirements