In order to understand cable TV it is best to look at what came before it.
In the early days of television there were only four networks. They transmitted, or broadcasted, their programs over radio waves, with the FCC assigning each television station a 6 megahertz portion of the radio spectrum. Since these frequencies were so specific, they could only be received by TV antennas in line of sight of the broadcasting antenna. People living in the mountains and remote areas were out of luck.
In the late 1940’s, enterprising people living in the hills of Pennsylvania, tired of not being able to see the programs everyone was talking about, discovered that if they erected an antenna on a hill close to their home and ran a cable from it to their television set, they got reception. Voila – the concept ofcable television was born!
Today’s cable providers use the same basic idea but on a much grander scale. Rather than using antennas,they use cables and satellites; satellites to collect channels from far off places all over the world and cables to receive more local channels. They then use outgoing cables to send programs to homes of subscribers.
Early on, the cables were coaxial cables and the signal traveling through them would get lost due to the distance involved. Adding amplifiers every thousand feet or so to amplify the signal solved the problem somewhat. Now, however, fiber-optic cable has replaced coaxial and since fiber-optics are not prone to signal loss, amplifiers no longer play a big part in transmission.
In order to prevent non-subscribers from free-loading by various jerry-rigging schemes, cable companies would scramble the signal. They accomplished this by inserting a signal a bit outside the channel’s frequency, to obscure the image, then filtered it out at the point the cable entered the subscriber’s television. Cheaters who didn’t have these filters saw a screen of jagged jumbled images.
The digitalization of cable television substituted encryption for scrambling. Today’s cable systems include a key that decodes the encryption so the show can be received.Cable installers insert a key card into the cable box to ensure viewers receive only the programs their selected subscriber packages entitle them to. Without the key, a viewer will only see a blank screen with a message they they are not authorized to see this channel.
Today’s viewers not only have a wide selection of entertainment packages available to them but depending on their location, a variety of providers to choose from, the major ones being Comcast, Verizon, Time Warner Cable, Cox Communications, & AT&T.