How Cable Television Works

In the 1950s, there were four television networks in the
United States. Because of the frequencies allotted to
television, the signals could only be received in a "line of
sight" from the transmitting antenna. People living in remote
areas, especially remote mountainous areas, couldn't see the
programs that were already becoming an important part of U.S.
culture.

In 1948, people living in remote valleys in Pennsylvania
solved their reception problems by putting antennas on hills
and running cables to their houses. These days, the same
technology once used by remote hamlets and select cities
allows viewers all over the country to access a wide variety
of programs and channels that meet their individual needs and
desires. By the early 1990s, cable television had reached
nearly half the homes in the United States.

Today, U.S. cable systems deliver hundreds of channels to
some 60 million homes, while also providing a growing number
of people with high-speed Internet access. Some cable systems
even let you make telephone calls and receive new programming
technologies! In this article, we'll show you how cable
television brings you so much information and such a wide
range of programs, from educational to inspirational to just
plain odd.

The earliest cable systems were, in effect, strategically
placed antennas with very long cables connecting them to
subscribers' television sets. Because the signal from the
antenna became weaker as it traveled through the length of
cable, cable providers had to insert amplifiers at regular
intervals to boost the strength of the signal and make it
acceptable for viewing. According to Bill Wall, technical
director for subscriber networks at Scientific-Atlanta,
a leading maker of equipment for cable television systems,
limitations in these amplifiers were a significant issue for
cable system designers in the next three decades.

"In a cable system, the signal might have gone through 30 or
40 amplifiers before reaching your house, one every 1,000
feet or so," Wall says. "With each amplifier, you would get
noise and distortion. Plus, if one of the amplifiers failed,
you lost the picture. Cable got a reputation for not having
the best quality picture and for not being reliable." In the
late 1970s, cable television would find a solution to the
amplifier problem. By then, they had also developed
technology that allowed them to add more programming to cable
service.