this post was submitted on 18 Dec 2023
154 points (89.7% liked)

things that are mildlyinteresting

689 readers
1 users here now

post things that are mildly interesting

founded 3 years ago
MODERATORS
 

None of the others in town have these, thought it was unusual enough to share

you are viewing a single comment's thread
view the rest of the comments
[–] Chobbes@lemmy.world 1 points 11 months ago

It’s a bit of a coincidence that the signal is in the audible range, for sure! I’m not too surprised that an MP3 can reproduce a digitally modulated sin wave in the audible spectrum, but I can see how it’s surprising to people that a sound card is basically a dinky low frequency SDR. Van Eck Phreaking is another good example of this kind of stuff. CRTs in particular produce very obvious emissions which match what’s being displayed.