TV in the hotel. How is it arranged?

Question

A television

Good time!
I was on vacation, I was lying clicking channels...
A couple of German, a couple of Russian, and a couple of local ones.. I think, yes, some kind of hodgepodge..
And then stop! How so?
How can you selectively sum the channels, and put them all into one coax?
And the second question:
The signals in the coax do not interfere with each other (One channel occupies a small frequency band).
Is it possible, roughly speaking, to crash into a coax and send another channel there, at a free frequency? If we say the task is worth it, add +1 channel to the entire hotel.
Thank you!

Answer 1

I described in this article . For a hotel also, only with other equipment and cheaper.