It’s wasteful to spend the power to broadcast up into the sky when no viewers are up there; more focused directional transmitters, more sensitive receivers which allow lower power signals, more information sent over cable and fibre optic and undersea transmission lines and point-to-point satellite, more microwave and laser links compared to spam-everywhere radio broadcasts.
As I understand it, the most visible stuff would be TV signal and over the horizon radar. TV signals have gotten less powerful, over the horizon radar is less of a big deal than it used to be. In another 50 years, will terrestrial TV, or any high power terrestrial radio, be a thing at all?
