There were stations on in the biggest cities on a experimental basis but officially TV broadcasting didn't begin until 1946 when the NTSC standard was approved. This was when NBC and DuMont began TV- and only to northeast cities. CBS and ABC didn't until 1948. The first big wave of stations went on in '48-49 but even by 1950 only fairly large cities had TV. In NC where I was- there was only 2 TV stations in the entire state until 1953.