This one's really stupid, especially as I wasn't so much a kid as a guy in my late-teens at the time, but when satellite tv first came out, I thought the presenters were actually on board a space station/satellite and were recording the programmes from up there...
A childhood belief about tv

others believed things like this
- When I was a kid I thought that the newsreaders on satellite TV lived in the satellites.— Mat
- I used to think that satellites were launched from satellite dishes.— Mike
- I used to believe that a weegie board was some sort of surf board.— Missa
- i used to think that vacuum cleaners had little piece of space inside them because space is a vacuumAnon
- When I was a kid, I thought the musical Mamma Mia did songs from the A*Teens (the teenage version of Abba)Anon
- I used to believe that boarding school was where people went to play board games.Anon