Satellite TV is a broadcasting service which allows subscribers to receive television signals through a dish-shaped receiver unit. These signals are originally uploaded to a communications satellite that is in a fixed orbit above the earth, then electronically scrambled to prevent unauthorized downloading. Those who pay a subscription fee for satellite TV service are issued both the receiving dish and a descrambler. The actual tuning information is fed into the television through a cable, much like earth-bound cable television services.
Satellite TV solves many of the problems associated with earlier television broadcasting methods. Television stations originally broadcast their signals in two specific radio wave bands- VHF (very high frequency) and UHF (ultra-high frequency). Aerial antennas placed on roofs or attached to the television itself would receive as much of these radio wave transmissions as possible, but the results could be barely watchable depending on the strength of the signal, the terrain between the station and the television set, and the atmospheric conditions. Cable television systems could provide a better television signal, but this involved stringing miles of insulated wire and creating subscription services.
Satellite TV provides a strong digital signal to subscribers' television sets and is almost completely wireless. Earlier systems used very large dish receivers in order to focus the distant signals onto a powered antenna. Since different television channels were located on different communication satellites, these dishes would have to physically turn to predetermined points in the sky in order to receive the proper signals. Because regulation of these early dishes was not uniform, illegal electronic descramblers became a lucrative underground market. Stiffer penalties for unauthorized descramblers paved the way for legitimate satellite TV subscription services.
Modern satellite TV services have streamlined the process. A single communication satellite now remains in a steady orbit above the Earth, allowing all subscribers to mount a much smaller dish receiver at a fixed point. Technicians from the TV provider may install the dish or owners can determine the proper receiving angle and do it themselves. Instead of scanning various satellites for different channels, modern satellite television providers license the use of popular cable or broadcast channels. Much like a cable system, the tuner descrambles selected programs sent out on a specific frequency. This allows satellite providers the option of pay-per-view movie rentals or the blocking of adult-oriented or premium movie channels.
Satellite TV services are especially popular in rural areas with poor broadcast reception and/or no cable service. Purchase of a receiving dish is generally limited to homeowners, not renters. Satellite dishes must have a clear line of sight to the satellite itself for best reception. Some homeowners discover that a grove of trees or mountainous terrain can be problematic. Critics of satellite TV also mention reception problems during heavy rains or snowfall. Signals between an earth-bound receiver and a space-based satellite can be affected by atmospheric conditions between them, but other television services also have similar drawbacks.