Eli5: How do TV broadcasting and TV stations work?

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I mean how does this whole thing work and where is the source of such broadcasts? Is there a worker who just presses some buttons or something in order to play a specific episode of a show? And how do all those subsidiaries of international channels function and what happens after a channel is deleted? So many questions, I know I’m sorry, but this topic has always been so fascinating and mysterious to me.

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>I mean how does this whole thing work and where is the source of such broadcasts?

There are big towers that send out the signal you are receiving. Radio/TV waves are like light, but invisible and can go through walls.

>Is there a worker who just presses some buttons or something in order to play a specific episode of a show?

Used to be, now it’s all on the computer. Like a playlist.

>And how do all those subsidiaries of international channels function

There’s a main station somewhere and they send copies of what to broadcast either ahead of time, or simultaneously.
>and what happens after a channel is deleted?

Nothing, it just stops blasting the radio waves.
>So many questions, I know I’m sorry, but this topic has always been so fascinating and mysterious to me.

Yeah, it’s pretty interesting.

In America over-the-air broadcast stations are individually licensed to broadcast in a relatively small area – 20-30 miles around a city for example. Most of these stations are owned by a larger corporate entity – Nexstar, Sinclair, Scripps and Grey being the larger ones in the USA. These groups get a lot of the programming for their stations from large broadcast networks like ABC/NBC/CBS/FOX/CW, along with program syndicators and “diginet” providers like Decades, Antenna TV, etc. Those programmers originate their content from network operations centers and sometimes provide timezone-specific feeds for different regions. Originally this content was distributed via satellite and it still is to some extent, but more and more networks are distributing content via terrestrial networks.

Every broadcast station has a “master control” operation which switches content from the programming sources to the transmitter. The master control system is a lot like an iTunes playlist. A daily log – created by the traffic department – is fed to the system to automatically run the shows and switch to live programming. The program schedule is created by the programming department, the sales department, the news department and the general manager. The sales department sells the commercials and arranges for the commercial content to be delivered to the station.

Every day the traffic department creates a log to send to the master control system, which identifies what content is present and what content still needs to be loaded. When something needs to be loaded and it can’t be loaded automatically an operator takes care of it. Live sources are provided to the input of the master control system so they can be switched to when needed.

Actual operation of the master control system varies depending on the station. Most station groups have “hubs” where multiple stations are controlled by a single operator. This makes a lot of sense since many stations will be running the same network programming at the same time so the technical execution station-to-station usually only differs during local commercial breaks. If a station does local newscasts or has breaking news some stations will shift control back to the local station for switching. Other stations are automated enough to allow the hub to do this switching.

Another big part of a TV station operation is cable and satellite TV distribution. Broadcasters extract huge sums of money from cable operators – who have to pay for the rights to retransmit content from the local station. Connectivity to the cable tv distributor can be as simple as them pulling down the over-the-air broadcast or as complicated as a dedicated fiber feed between the station and the cable operator.