Understanding Satellite TV SystemsThe increasing popularity of satellite television has brought forth the existence of more and more satellite TV systems provider all over the world. In the United States, DirecTV and Dish Network are two of the most successful satellite TV systems provider. Aside from competing with other providers, they also compete with cable television for a major chunk of the market. In the past, television viewing is limited to broadcast television. The latter relies on an antenna to pick up signals coming from a broadcast station to be able to view a particular channel. The main problem with this setup is that television antennas should be in straight line of sight of the transmitting station to obtain a clear signal. Obstructions like small trees and buildings results to bad signal receptions. Satellite TV systems have been offered as solutions to this dilemma.
Satellite dishes are used by satellite TV systems for their subscribers to receive signals. Television satellites, which are launched into geosynchronous orbit, transmit these broadcast signals to the end-user. Since these are in geosynchronous orbit, they remain in the same place in the sky as the Earth rotates. Moreover, more customers are in its line of sight because the satellites are perched high up in the sky. There are four major components of direct-to-home (DTH) satellite TV systems and these are as follows: program source, broadcast center, television satellite, dish satellite and satellite receiver. A program source can be a channel that offers programs to be broadcasted or it can be another company that owns right to broadcast a program. The broadcast center, on the other hand, is where the satellite provider gets signals from the program source. These signals are then transmitted to satellites present in geostationary orbit. The satellites in the sky retransmit these signals to Earth. A satellite dish in the home of a subscriber picks up these signals and relays it to the receiver. The latter transforms the signal into a format that can be understood by a standard television. Commonly, satellite TV systems utilize the MPEG-2 compressed video format, the format also used for DVD movies. With this compressed format, it is possible to transmit an estimated 200 channels at one time. This is how companies like DirecTV and DISH Network are able to provide these many channels to its subscribers. Before a video is transmitted and after a video is compressed, satellite TV systems place an encryption on a signal to prevent people without subscriptions from accessing it. When encrypting, the digital information is scrambled and can only be converted back into useful data upon input of correct security keys and correct decryption algorithm. Broadcast signal is then transmitted to one the geostationary satellites after digital information has been compressed and encrypted. Moreover, an onboard dish that all satellites carry, receives the signal. After a signal is amplified, it is then rebroadcast to Earth using another dish. The transmitted signal is then picked up by satellite dishes installed in the homes of subscribers and are processed for use of standard televisions. |