I knew that it was possible to spy on CRT displays due to the signals they radiate, but apparently that is a problem with HDMI too.
Here a very interesting write up on how to extract frames from leaked RF from HDMI cables and using said RF to transmit a webcam stream even: https://www.windytan.com/2023/02/using-hdmi-radio-interference-for-high.html
Here a example of someone using HDMI RF to transmit LoRa signals: https://www.youtube.com/watch?v=HDbdAZd6cLw
This makes for a interesting attack vector for locating a user, if said user clicks on a video (or even a gif) that crafts LoRa frames to radiate from his HDMI and there is for example a Meshtastic receiver near by that relays those frames into a wider network.
There are ways to migrate this issue, for example using the encrypted version of HDMI usually used to enforce content copyright protection, or using a fiber optic HDMI cable (by now they are almost as cheap as the copper ones and are not restricted to a max lenght of 5m).
I assume its because the Nintendo back then probably had a switcher on the back of the TV to inject the display in your RF antenna coax. That coax was probably connected to your TV antenna, so you got low emission transmission.
A guess. And still pretty cool
Close, the NES actually broadcasts a standard NTSC RF signal on its output. The old TVs were acting as a broadcast antenna for the others to pick up. You can do the same thing with some decent rabbit ears by just putting a paperclip into the center pin of the RF output on the side of the console. Don’t play that way though, you would be technically operating a pirate TV station if you didn’t have a license to broadcast on that channel. The NES should be a low enough output power that it doesn’t matter either way.
Fun fact: before superheterodyne radios were invented, you needed a license to operate a radio including just to plug it in and tune it.
The reason is simple regenerative radios back In the day were also transmitting a small amount of signal back when they were receiving a station. As a result, at least in the US you needed a radio operator’s license to listen to a radio since you were technically transmitting.
Super heterodyne radios fixed this though by having extremely levels of sensitivity and basically now backfeed signal transmitted.
I love seeing mentions of superHets in the wild. Back in my day we sparked car batteries across a measured loop of wire!
Well the TVs only had one coaxial so maybe the receiver tv was hooked to an antenna (probably a set of rabbit ears) but the sender wouldn’t have been.
I think we did try messing around with the antennas but it was so long ago I can’t be sure. But maybe messing with them is what improved the signal. I do remember for sure we improved it.