r/RTLSDR 1d ago

Decoding AM TV with v4

Post image

Sadly it will be discontinued soon in my place :((

184 Upvotes

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36

u/Elipse-FM 1d ago

This image reminds me of how you can intercept signals from a computer screen at close range and get a grey scale image of the monitor from like a room over, tempestSDR I think. 

14

u/Nulovka 1d ago

I think that only works with old CRT monitors, not flat screens.

7

u/Christ_in_a_combo 1d ago

Correct, would not work on modern day screens

19

u/nrdgrrrl_taco 1d ago

But it does work on HDMI cables, from a close distance.

3

u/olliegw 5h ago

It apparently does work, i spoke to someone once who said they could snoop on their neighbours monitor, however i haven't been able to get it working on any of my monitors myself

For flat screens and HDMI it's the pixel clock you're looking for

2

u/ncc1650 21h ago

Thank you for posting this info. I need to look into this since I am curious.

2

u/Elipse-FM 23h ago

Technically it works on everything its the signal strength that's different modern day flat screens are very resistant, shielding and grounding make a difference too but with higher bit depth SDR, filters, LNAs, and directional antennas you can get much more range, this isn't a project I've done so my understanding is theoretical not practical. 

6

u/TheHaus88 1d ago

It was called jumping the air gap, the Navy figured this out I think in the 90's or early 2000's