Best Way To Set Up Scanner

I have a bunch of different civil aviation frequencies programmed into various scanners.



"Low, HI, SH." etc.



I came upon the idea of being able to hear the control tower and the airplane by listening to the control tower stream online! (smart idea right?)



Well...I end up being able to hear the chatter on the stream but none of my scanners are picking it up! I do pick up other airplanes talking but I don't hear it on the ATC stream.



So I'm confused. What's the best way to program a scanner? Do I set it up by airport or what? Or is the ATC and airplane chatter low power or something?



Thanks so much for any ideas.

Best Way To Set Up Scanner