Ghost Play?

[Ganelon]

There was a mystery I always had from a long time ago and was hoping some tech experts here could help answer it. About 1995, I was on vacation in China playing my Famicom. I finished a session of Contra in my grandparents' apartment and unplugged the RF cable from the TV. As I was plugging in the RF cable from the cable box for TV viewing, I was shocked to see a fuzzy image of an NES game being played on-screen. I could faintly make out the colors under the snowy screen and it looked like Double Dragon III!

I didn't have Double Dragon III and never even played the NES version so it was a huge surprise. The only way I recognized the game was because of the unique character select screen and Egypt level. I checked my system and sure enough, it was turned off. The game wasn't motionless either. Someone was actually progressing through the levels. There was no such thing as a video game channel at the time and none of the channels had Double Dragon III on when I fully plugged in the cable box to the TV and flipped through the channels. It wasn't a perfect play either since the player was dying at times.

I could only stick around 10 minutes before I had to leave. Ever since then, it's always baffled me what I was watching. I'm 100% I was wide awake at the time with no mental impairments. My immediate suspicion was that... a ghost was playing! Nah my immediate suspicion was that my TV was somehow picking up interference from someone else in the apartment complex playing Double Dragon III. Now, for those pf you more familiar with TVs and signals, can you explain what I was seeing? Was this type of stuff possible on old signal-leaking cables? And if so, is it still possible?

[Fudoh]

Nah my immediate suspicion was that my TV was somehow picking up interference from someone else in the apartment complex playing Double Dragon III

exactly that.

[shmuppyLove]

[Ganelon]

Nah my immediate suspicion was that my TV was somehow picking up interference from someone else in the apartment complex playing Double Dragon III

exactly that.

Can you explain the basic physics behind this phenomenon? Is this still possible today using a very unguarded HDMI cable? How far can these signals leak?

[blizzz]

I know that you can listen to radio with a cooking pot, but how would a video signal get from one TV to another? Via the powerline? I think that's highly unlikely. Would be really interesting to know how that worked.

[Fudoh]

It's not possible via HDMI.

Back in the days the videogame systems were connected using modulated RF signals, basically the same modulation for TV channels on analogue cable/free-to-air. The coax cable for analogue TVs runs through the whole building and if the TV along with the cable isn't properly terminated then the signal can get reflected and is retransmitted into the signal path....

[rugdoctor]

Freaky.

[-SD-]

The Master System Compact and MSgirl have built-in RF transmitters to send their signal to the TV wirelessly. I would imagine there's Famiclones with the same ability. Maybe you were picking up the signal from one of those?

[Ed Oscuro]

The Master System Compact and MSgirl have built-in RF transmitters to send their signal to the TV wirelessly. I would imagine there's Famiclones with the same ability. Maybe you were picking up the signal from one of those?

There's actually an official SG-1000 RF transmitter (Mark III, aka Japan's equivalent of the SMS base system through most of its life, although it needed a couple addons to work as well - just like Nintendo, Sega streamlined things for a release over here; although where the NES lost the disks and the extra disk channel, the Sega system lost FM sound). I didn't know about a compact having this, although I do recall seeing pictures of that pink master system (also a Tec Toy release for Brazil).

I didn't make a connection to the Famicom though - my first search found this, so it does look like these products weren't unknown (especially in China which would have been near where they were being made).