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@jimfenton recorded some audio from Cartoon Network in an attempt to find these beacons: http://altmode.org/2015/11/13/searching-for-ultrasonic-beacons/ http://

by sehugg 11y ago

@jimfenton recorded some audio from Cartoon Network in an attempt to find these beacons: http://altmode.org/2015/11/13/searching-for-ultrasonic-beacons/ http://altmode.org/2015/11/13/searching-for-ultrasonic-beaco... FSK at 17.5 and 18.5 kHZ is one possibility, but wasn't detected in this experiment.

jevinskie 11y ago
Awesome, thank you for posting with this! I was getting ready to fire up ffmpeg with my network TV tuner to begin searching for this. Now I know of one thing to look for.
simoncion 11y ago
To nit-pick: Anything under 20kHZ isn't ultrasonic. :) (Not that either you or the blog author called this high-frequency signalling "ultrasound", but it does appear to be what people are calling it. :/ )
- digi_owl 11y ago
  But it seems to fall into the range used by those "mosquito" devices. Meaning it is on the edge of what most humans can hear at young age, and lost with age.
  - simoncion 11y ago
    No doubt. It's still not ultrasonic. :)