How Satellite TV Works
The television started with broadcast TV. It was VHF broadcast at first. Later UHF also started but all these broadcast TV systems had to face the problem of signal distortion. The reason is the obstruction of the signal. These radio signals could penetrate through small objects such as trees and houses but when they hit mountains they could not penetrate. Even in the flat land they could go a long distance as the earth’s spherical shape drives the signal away.
The solution found successful was to send the signal to geostationary satellite and to get it to dispatch it. This way a transmission from one satellite could reach at least a third of the earth. The transmission is done by the earth stations of the TV channels through dish antennas. They use huge antennas for the purpose. The signal that comes back is caught by smaller dish antennas in houses where the receivers will decode the signal to enable the TV to display it as picture and sound.
The first satellite broadcasts used radio signal to send and receive the TV broadcasts. After the digital revolution came in, the satellite broadcasts too started using the digital signal. This enabled the reception to be made clearer. The early satellite dish antennas were large ones but with the improvement in digital technology and broadcasting, things changed for the better. Present day dish antennas are very small and could be installed in a small space.
It is obvious that the signal that comes to earth could be received by anyone who has a dish antenna and a receiver but this is prevented by sending encrypted signals. To decode these signals the user must buy an intelligent card that is programmed to decode the signal. This card once inserted into the receiver will do the job of decoding. The earlier cards were not safe from pirates who resorted to finding the programs from the cards and producing copies but with the new digital cards it is difficult to decode the program to copy.
The cable TV companies receive these signals with their instruments and distribute them through their wired networks. This is cheaper to start as the need to buy equipment doesn’t arise. But with the lowering prices of electronic goods these items might become cheaper. When that happen; satellite TV will become more affordable. The dish antennas too are getting smaller making it possible to have them in small spaces.