The Ups and Downs of Satellite TV

A satellite is an object that orbits some other object. The moon is an example of a natural satellite of planet Earth. There are also many artificial objects launched into space for any number of reasons. This has become the age of spy satellites, weather satellites, navigation satellites, science satellites, communication satellites and TV satellites.

A satellite is an object which is basically unmanned. There are no humans on board and no humans are there directing it by hand. It is an artificial object which is floating around in space. Satellites are made up of electronics and systems which may include power stations and transmitters. They are sent signals via Earth then relay those back to Earth.

Our concern here is with TV satellites. Each day, thousands of people purchase this exceptional technology to watch TV at home. Since the early 1980s, satellites have transmitted TV signals right into our homes. This was known as DBS or direct broadcasting by satellite. These signals had to cover a very large area and in turn needed to be very powerful. A dish was required as well as a decoder connected to the TV set.

In the decade of the 1990s, more advancement was made in transponders, batteries, and satellite solar cells. This resulted in far more powerful signals over a much wider area. The series of DBS satellites launched back in 1996, in Europe, are known as Hot Birds. They provide service to most of that area. The rest of the world is also developing similar systems.

In America there are hundreds of TV channels available by satellite. To understand how such a system functions, consider the following. The TV studio becomes the point of origin for a program. The TV signal is sent by uplink from a ground station dish. It is sent to an Earth orbiting satellite.

The satellite then sends the signals on a downlink to be received by individual homes or businesses by way of the dish or to a ground station dish to be transmitted through a system of land line cables and broadcast masts. The DBS dishes must be pointed or aimed exactly at the correct satellite. That is why they are permanently affixed to the roof or side of a home or office building. They always face in the desired direction.

In the future, a ground station could be as small as a helmet equipped with dish and portable viewing screen. We already have portable ground stations that can fit into a van or can even fit into a car or suitcase. There are two words you should become familiar with.

The first word we are going to cover is uplink. Satellite programming originates in a studio and is carried to a large transmitting antenna, aimed at a precise spot in space, which is the location of the desired satellite. Transmission is carried at 5,900 to 6,300 MHz. The second word we should know is downlink. Satellite programming is relayed by means of a downlink transmitter on the satellite, back down to earth where it spreads to cover a vast area. This is carried on at about 3,700 to 4,200 MHZ.