Difference Between Cable TV And Satellite TV
Cable TV is a system for delivering television signals by means of cable. Radio frequency signals are spread through coaxial cables or fixed optical fibers. Cable television was the only feasible solution in countries where transmission was difficult because of geographical or climatic conditions. This led to the launching of the cable TV system in 1948. Cable TV is currently used on almost all continents.
In the past, television stations delivered signals over the air to individual TV sets equipped with standard antennas. Cable TV viewers received a variety of services in return for an installation fee and monthly subscription charges. Clear pictures of local broadcast channels were offered. For extra fees viewers could receive scores of additional channels (by 2009 the average number of channels was 180).
Satellite Television and Radio, two systems of communications (video and audio) that rely on earth-orbiting satellites to extend the range of a broadcasting station’s “footprint,” or coverage area. Both systems function in essentially the same manner, although they do operate on different bands of the electromagnetic (radio-wave) spectrum. Both serve as alternatives to traditional forms of broadcasting and, in the case of television, to cable TV.
The relaying of television signals by way of a domestic satellite system was first suggested by the American Broadcasting Company (ABC) in 1965. This idea began to receive serious attention in the 1969–1970 season after the American Telephone and Telegraph Company (AT&T) raised its annual rates for terrestrial network interconnections. At the time communications satellites orbited around the earth at relatively high speeds (faster than the earth’s rotation), forcing receivers to track their motion across the sky in order to obtain a continuous signal. A significant development occurred in 1974, when the first geosynchronous (or geostationary) satellite was launched. Its orbital velocity exactly matched that of the earth’s rotation, allowing it, in effect, to hover at a distance of 22,300 miles (35,890 km) above the planet’s surface. Henceforth broadcasters could more easily uplink their signals for transmission back down to ground stations and television viewers could employ satellite dishes—antennas shaped like shallow bowls—directed at a single, fixed location in the sky.