Beacons found in the wild !

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kelu124kelu124 01/13/2018 at 21:570 Comments
Some time has passed, but I'm willing to go back to some hardware for going fishing ultrasound beacons!
I'm gathering some info about these beacons - so I've been walking around with my phone to fish some interesting sounds.
Some examples include a beacon in a starbucks close to montparnasse : interesting central frequency at 20khz, and two side freqs at +-250hz

The spectrogram shows it continues:

On another hand, I was in a coffee (called Ajami possibly), and I found a nice peak around 20khz:

Now, all I need is understand what is inside =)

For those curious, data and code are at  -- feel free to come and play.