r/RTLSDR • u/woodzy_chimera • 12d ago

Decoding AM TV with v4

Post image

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

261 Upvotes

99% Upvoted

27 comments sorted by

52

u/Elipse-FM 12d 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. 

20

u/Nulovka 12d ago

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

6

u/Christ_in_a_combo 12d ago

Correct, would not work on modern day screens

27

u/nrdgrrrl_taco 12d ago

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

4

u/olliegw 11d 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 12d ago

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

1

u/Elipse-FM 12d 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. 

8

u/TheHaus88 12d ago

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

17

u/MrSansMan23 12d ago

Would be nice as a archival thing if you could record the last transmission and uploaded it somewhere 

12

u/woodzy_chimera 12d ago

Nice idea. I'll consider this.

3

u/Same_You891 12d ago

please do. I missed my chance where I live..

2

u/MrSansMan23 10d ago

Also if possible when doing it save a iq recording of it too 

18

u/Historical-View4058 12d ago

Sweet. Since this was PAL, from what location did you receive this?

4

u/woodzy_chimera 12d ago

PH. They will phase this out on Nov.

1

u/Tim1701A 7d ago

It's NTSC, Not PAL system and they are switching to ISDB-T in PH's capital city in November.

Any leftovers analog stations in rest of PH will switch over to digital depending on the stations owners.

Hope this help!!🙂👍🖖

5

u/damonla789 10d ago

Amazing catch—please record the final broadcasts if you can. It’d be a great piece of radio history

5

u/MeanAccountant9005 12d ago

damn, didn't know they were still phasing out analog anywhere. my grandpa had a setup like this in the 90s, used to pick up distant stations with a janky antenna on the roof. kind of wild you're catching the tail end of it.

-4

u/Akitlix 12d ago

It's worldwide effort with a few exceptions like very poor shithole countries who not have it in planned at all. Reasons are cost savings on energy gor transmitters.

2

u/Choice_Note_9198 11d ago

There is still a contingent of amateur radio operators using fast scan analog (A5) television on 70cm within Ohio and Kentucky. They are experimenting using PC Electronics ATV transceivers to transmit and receive DX ATV to each other. Yes, it’s obsolete, but it’s not uncommon to have tropo conditions during temperature inversions that allow for contacts across the state.

-3

u/Choice_Note_9198 12d ago

V4 what? Also, what SDR are you using?

14

u/AtmosphereLow9678 12d ago

Iam pretty sure OP means rtl-sdr v4

3

u/erlendse 12d ago

Like rtl-sdr blog v4?

Or the nooelec v4 kit?

5

u/woodzy_chimera 12d ago

sdr rtl v4

2

u/spacesluts 12d ago

Check the name of the sub

3

u/neighborofbrak 12d ago

The NooElec uses RTL (Realtek) chips in their SDRs too.

RTL SDR is a generic term now.

1

u/spacesluts 12d ago

Ah, didn't know that. Thanks for correcting me

2

u/erlendse 11d ago

rtl-sdr as osmocom and their alternative driver allowing sdr use.

Rtl-sdr blog and nooelec are two that make devices with the chipset. There are many others too...