This system was built by Mike Manes, W5VSI. Some detailed system photos are available here.
This beacon is frequency agile. That is, it may appear just about anywhere within the 2 meter (144 MHz to 148 MHz) band. The frequency will be published in the Flight Announcement.
The beacon uses an Alinco DJ-C1 transceiver. The output signal is transmitted at around 350 milliwatts.
The beacon transmits a standard Morse Code id including (depending on programming for each flight) the call sign of the beacon and possibly the flight number. The Morse code is usually sent at around 5 words per minute.
ae0ss_sound_clip.mp3 - An explanation of the beacon and one cycle of the audio received at a distant station (~77 miles).
This payload is often flown as a backup for tracking and recovery purposes.
The Beacon also incorporates a cut down system. A receiver monitors an uplink frequency for a DTMF code to actuate a cut down device. When received that device is activated and depending on what it's programmed to do, may cut away the balloon, or perhaps activate some type of experiment. 99% of the time it's a cut down command, but sometimes we fly payloads that need to be commanded to take some action and this payload is capable of passing along an actuation command to another piece of hardware.
For Basic Stamp I Processor