Preface.

This article is dedicated to radiospotters who are also interested in broadcasting radiotalks to Internet. Often it turns out there is a wish to broadcast, but no technical opportunity. Not anyone is ready to use PC, laptop as broadcast station and there are several reasons. PC can be noisy and eats a lot of power and sometimes is occupied by relation. With laptop situation is even worse, you are supposed to take it with you sometimes. In this article I will tell about simple and relative cheap solution, which allows broadcast air to Internet w/o noise and big power.

  

Components.

Solution is based on Beaglebone. Board has Ethernet and USB ports. Board is lack of soundcard, however today you could buy it on Ebay or Dealextreme for $2-3. It won't be high-quality for music capture but rather good for speech.

If you have Uniden scanner and wish to broadcast not only audio but channel metadata and also archive audio by channel, than you have to purchase UBS-hub. It's needed to plug in rs232 usb cable to control scanner and soundcard. Dealextreme suggests some for 5-8 US dollars. I recommend to use 4-port USB hub, because more ports, more power from board, and once board cannot supply infinite power some ports will be down.

If scanner has Line-out it is worth to buy more expensive soundcard with Line-in. Also I recommend to purchase noise-reduction cable to eliminate electrical noise.

Software.

Software is based on Darkice. For VOX emulation feature mp3splt software is used. Board can work in three modes - record, broadcast and record, only broadcast. You can access files via samba protocol from Win/Mac/Linux machine. Special script performs disk clean removing old records to allow continous record.

Configuration.

Configuration is very simple. Put text file onto partion where scanner audio archive is stored in special format. Format is a comma-separated line with following parameters - a) scanner type (1 - controlled or 0 - not), b) scanner port, c) sound card port, d) record mode, e) host and port, f) password, g) mount point, h) compression quality (lq - low, mq - moderate, hq - high). High quality consumes more processing power. If air is clear it will better to use low quality, if very noisy - high quality.

Demo audio.

Archive with demo audio files which software generates can be downloaded here - demo_audio.zip.

Solution price.

Beaglebone - $89, case (optional) - $17, USB soundcard - $3 ($8,$20), USB hub (optional) - $5,...