You know those radio stations and TV stations and cell towers and everything that’s bombarding you with radio waves all damn day, which is useless for you if you don’t have one of those devices turned on? Dude has built a rectenna to capture those and generate a small amount of electricity.
Now, of course he only got a very teeny amount of power out of it. But a teeny amount of power, which would otherwise be wasted anyway, can still be used to trickle charge small devices all day long. It might not mean your cell phone never ever winds down, but it might get you a longer charge out of the deal. At any rate, it’s an interesting idea.