What Is Satellite TV?

Satellite service can be defined as a service of broadcasting TV signals, in which subscribers directly receive signals of TV through a receiver unit having shape of a dish. Sending of this signal is controlled and monitored by a high tech communication satellite, which is present in its fixed orbit above the atmosphere of earth. Original signals get uploaded in theses satellites only, and then regulated sending of signals takes place from this main satellite to all linked receivers present at planet earth. Subscribers pay a certain amount to get an authority to receive these signals officially. Dish shaped receivers pass this signals to the TV, to display received programs.

Why satellite TV?
Satellite TV is a solution of many traditional broadcasting problems. In traditional broadcasting system, TV stations transmit signals free to air, which then directly received by users through installed antennas. These TV stations broadcast TV signals in two different bands of radio waves. These radio wave bands are- UHF (ultra-high frequency) and VHF (very high frequency). Now a user receive these signals by means of roof Aerial antennas or by means of antennas which are assembled with TV sets itself. But this broadcasting system was not able provide a clear appearance of the signals on TV screens, because it strongly depends upon the strength of the signal, distance between the transmitting station and receiving antenna and on various other climatic factors. Cable TV system is a very good alternative of this traditional broadcasting. But because of heavy work of cabling for proper distribution of signal, subscription of cable services is very expensive.

Earlier satellite TVs
Because of above mentioned problems, satellite TV broadcasting system appears to be much better option. Satellite TV is the solution of various broadcasting related problems. Satellite TV provides a service of strong TV signal, without any wires. But, traditional satellite TV systems were enabled with very large sized dish receivers, because technology of transmission and receiving was less developed in earlier times. But modern dish receivers are compact in shapes and they also have an attractive appearance.

Moreover, earlier dish receivers were direction sensitive. So to receive complete signals from communication satellites, it was a must to adjust these dishes according to standard points of the sky. This was very tedious for subscribers. As a result earlier satellite TV system was near to flop according to performance and service.

Modern satellite TV
Modern satellite TV is a much more advanced system of broadcasting. It fills all the flaws of earlier satellite services. Modern dish receivers are not bulky and heavy in appearances. They have very compact sizes; it’s very easy to install them and a small space is required to make a connection of the dish. For signal receiving these dishes use transmitted signal of geostationary communication satellites, as a result there is no need of adjusting angles of dish to get a continuous signal. Moreover, installation of modern dish systems is very easy and economic.

Those companies which provide services of satellite TV, they always have contracts with popular TV channels. So they claim a license to broadcast signals of all those channels which are in public demand, this feature enable all the subscribers to visualize free as well paid channels with extraordinary quality of signal. Moreover satellite TV companies also provide special services of requesting a movie or a repeat telecast of a TV program. In this way satellite TVs are introducing a new definition of signal broadcasting and entertainment.

Satellite Definition

In general, a satellite is anything that orbits something else, as, for example, the moon orbits the earth. In a communications context, a satellite is a specialized wireless receiver/transmitter that is launched by a rocket and placed in orbit around the earth. There are hundreds of satellites currently in operation. They are used for such diverse purposes as weather forecasting, television broadcast, amateur radio communications, Internet communications, and the Global Positioning System, (GPS).

The first artificial satellite, launched by Russia (then known as the Soviet Union) in the late 1950s, was about the size of a basketball. It did nothing but transmit a simple Morse code signal over and over. In contrast, modern satellites can receive and re-transmit thousands of signals simultaneously, from simple digital data to the most complex television programming.

There are three types of communications satellite systems. They are categorized according to the type of orbit they follow.

A geostationary satellite orbits the earth directly over the equator, approximately 22,000 miles up. At this altitude, one complete trip around the earth (relative to the sun) takes 24 hours. Thus, the satellite remains over the same spot on the earth's surface at all times, and stays fixed in the sky from any point on the surface from which it can be "seen." So-called weather satellites are usually of this type. You can view images from some of these satellites on the Internet via the Purdue Weather Processor. A single geostationary satellite can "see" approximately 40 percent of the earth's surface. Three such satellites, spaced at equal intervals (120 angular degrees apart), can provide coverage of the entire civilized world. A geostationary satellite can be accessed using a dish antenna aimed at the spot in the sky where the satellite hovers.

A low-earth-orbit (LEO) satellite system employs a large fleet of "birds," each in a circular orbit at a constant altitude of a few hundred miles. The orbits take the satellites over, or nearly over, the geographic poles. Each revolution takes approximately 90 minutes to a few hours. The fleet is arranged in such a way that, from any point on the surface at any time, at least one satellite is on a line of sight. The entire system operates in a manner similar to the way a cellular telephone functions. The main difference is that the transponders, or wireless receiver/transmitters, are moving rather than fixed, and are in space rather than on the earth. A well-designed LEO system makes it possible for anyone to access the Internet via wireless from any point on the planet, using an antenna no more sophisticated than old-fashioned television "rabbit ears."

Some satellites revolve around the earth in elliptical orbits. These satellites move rapidly when they are near perigee, or their lowest altitude; they move slowly when they are near apogee, or their highest altitude. Such "birds" are used by amateur radio operators, and by some commercial and government services. They require directional antennas whose orientation must be constantly adjusted to follow the satellite's path across the sky.