How Cable TV Works

Beginnings

Cable TV started as a means of getting around the problems of traditional antenna TV, which relies on a direct signal from the station's broadcast tower to the antenna on top of your home. The further your home is from the station, the weaker the signal becomes and the more obstacles such as mountains and hills get in the way. (Eventually, the curve of the Earth itself begins to interfere with the signal.) Television viewers in rural areas would solve the problem by posting antennas on hilltops and running cable down from it into their homes, which provided stronger reception.

Satellite Signals

Today, cable companies rely on the same basic principle, though they have refined the process considerably. Instead of traditional antennas, they use satellite dishes to collect signals from the various different stations included in their packages. HBO, TBS, ESPN and other cable stations beam their programs up to a satellite and then back down to the dishes controlled by the local cable company. The process eliminates signal problems caused by the landscape or the curve of the Earth, ensuring that a pristine signal arrives at the cable company headquarters.

Local Signals

In addition to satellite broadcasts, local broadcast stations send their signals to the cable company through fiber-optic cables. Because of their close physical proximity, they don't need to use satellites in order to ensure a clear signal.

The Cables

Once the signals from all the different stations are gathered by the cable company, it scrambles them to keep them from being picked up by people who haven't paid for the service. It then goes out to subscribers homes via a network of cables; signal amplifiers are spaced around the local area to ensure that the signal remains strong. The cables run up into your house and into a receiver on top of your television, which descrambles the signals and allows you to pick up the various channels.

Benefits

The primary benefit of this system is the clarity of signal which it allows. Because it travels directly through the cable, it can't be disrupted by physical obstacles between you and the broadcaster, and comes into your home with no ghosting, snow or distortion. Furthermore, cable services allow you to pick up stations from anywhere in the world, regardless of where you may be. CNN, for example, is broadcast out of Atlanta, while ESPN's studios are in suburban Connecticut. Thanks to cable TV, anyone in North America can receive those stations as sharply and clearly as if they were next door.