Jerry Feldman wrote: > Tom Metro wrote: >> A self-taught signals & electronics hacker from Helsinki spotted a >> curious pattern in an audio recording of a helicopter and figured out >> how to decode it...and what it meant. >> >> Mystery signal from a helicopter >> http://www.windytan.com/2014/02/mystery-signal-from-helicopter.html > > ...helicopters have 2 different vibration levels, low freq and high > freq. ... The low freq is caused by the main rotor blades. ... The > tail rotor is the cause of the high freq.
Interesting, but did you read the article? It wasn't about an analog sound resulting from a vibration, but instead a digital signal imposed on the left audio channel, that when decoded turned out to contain the GPS coordinates of the helicopter. -Tom _______________________________________________ Hardwarehacking mailing list [email protected] http://lists.blu.org/mailman/listinfo/hardwarehacking
