Wait for people to learn about that you can listen in virtually anywhere through fiber-optic cables, as sound waves are enough to redirect the light in the cable to a measurable degree by "bending" the cable itself. Special devices to filter these variances out and transform them back to audio signals are a thing. It's only per line though, as any repeating device will just output a new cleaned up signal again.
Oh well, there have always been ways to snoop on someone like that. Back in the day it was CRTs emitting measurable waves through the neighborhood, with some papers even going as far as restoring the displayed image through a wall. Nowadays it's fiber and WiFi, and those seem to be much easier to work with even. Plus everyone carries a device that is tracked by their mobile provider's cell network. shrug
armcattoday at 9:02 AM
Several years back we actually made use of the principle mentioned in this post, to more systematically count traffic on the roads [1]. In our case we used LTE/4G radio, and we could even estimate the direction of travel, as well as the type of traffic (pedestrian, small vehicles, large vehicles). It was more accurate than Google Maps because it was independent of the moving phone, i.e. it was "sensing the obstacles in the environment".
As anyone observed who had a TV with just basic analog terrestrial antennas, before cable and satellite dishes - it does make a difference to the signal, when and where you stand and countless pieces of physical comedy in TV shows incorporated that.
1e1atoday at 7:33 AM
See these for a very low cost (<$10) method for observing WiFi and some LTE spectra:
I thought this article was going to be about putting a webcam on the other side of the wall and streaming through the TV, which somehow had never occurred to me and I want to try it now.
fzeindltoday at 7:06 AM
Amazing book about similar topics: “Silence on the wire” by Michal Zalewski
I know this is written to sound scary, but it's been like this since the invention of the radio/telegraph (late 1800s?). You're getting blasted by rf almost continuously, unless you live in a bunker.
reactordevtoday at 12:55 PM
I threw away all TVs in my house after the proliferation of ads on the Home Screen. Sorry, the only value a TV has is displaying images and audio at large sizes. Not getting me to shop. So I decided to get rid of them all and now I use large monitors and projectors. Make TVs dumb again.
rapnietoday at 2:03 PM
Tangential. Of both LG [0] and Samsung [1] smart TV's it is known they spy on you any way they can. Does someone know if they do that too for models sold in Europe, which would likely be in violent breach of GDPR?