Comments on: Information leaking on apps, pictures and video https://www.epanorama.net/blog/2014/02/02/information-leaking-on-apps-pictures-and-video/ All about electronics and circuit design Sun, 10 May 2026 18:53:06 +0000 hourly 1 http://wordpress.org/?v=3.9.14 By: Tomi Engdahl https://www.epanorama.net/blog/2014/02/02/information-leaking-on-apps-pictures-and-video/comment-page-1/#comment-83177 Sun, 02 Feb 2014 08:50:36 +0000 http://www.epanorama.net/newepa/?p=24712#comment-83177 Slashdot also mentions this great helicopter telemetry hack, and mentions another way to decode the data stream from the helicopter using off-the-shelf software:

Finnish Hacker Isolates Helicopter GPS Coordinates From YouTube Video Sounds
http://tech.slashdot.org/story/14/02/01/1816215/finnish-hacker-isolates-helicopter-gps-coordinates-from-youtube-video-sounds

Comment:

You can decode it with off the shelf software, throw away the top bit, and get back mostly ASCII:

$ ./minimodem –rx 1200 -f ~/helicopter.wav | tr ‘\200-\377\r’ ’00-\177\n’
### CARRIER 1200 @ 1200.0 Hz ###
282 0002.3
#L N390374 W09432938YJ
#AL #NA 282 0002.3
#L N390374 W09432938YJ

This is pretty much as basic as telemetry data modulation gets!

This is exactly the same sound as 1200 baud AFSK amateur packet radio made in the eighties/nineties, indeed using Bell 202 AFSK modems.

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