Satellite Communication
All over the world, the interest and imagination of man have been captured by the advent of satellite communication. It provides economical and reliable trans-mission of signals including voices, teletype, data that interconnect the whole world.
The basic advantage in this kind of communication is that the distance and terrain do not affect the cost and performance of the circuits. This is very helpful where the distance is very long and setting up of conventional system of communication is highly expensive. Hence the satellite provides the best medium for connecting remote parts of the country with the mainland.
The satellite communication was initiated by the USSR in 1957, when the first sputnik was launched. This was followed by various satellites launched in quick succession by the USA and the USSR. But only in 1963 and 1964 by launching Syncom 2 and 3, the geo-stationary -Satellites, the USA heralded a new era in satellite communication. But these were more of scientific test than of immediate utility.
Commercialization of satellite followed much later when it became a reality. Commercial satellite communication is based on the use of geosynchronous satellites. The geosynchronous orbit is at a height of about 35,800 kms above the equator. A satellite appears fixed in space with reference to an earth station on the ground. This dispenses with tracking electronics and antennas.
Since one satellite cannot, provide communication all over the world on account of the earth’s curvature, we have to put up three satellites in synchronous orbit with geo-stationary satellites. Long distance calls from earth to satellite and back may cause delays in telephone conversation. But this delay is negligible and people can adopt themselves to the delay. One way services such as television, telegraphic messages and data traffic are not at all affected by the delay.
Remarkable advances have been made in the use of satellites for international trunk calls. By late sixties, satellite communication. has helped very much in quicker and cheaper international communication.
For its nationwide trunk services, the P&T Department has been establishing country wide network of coaxial cable system and line of sight radio relay system. But even this service is not satisfactory for isolated parts and island communities and between widely separated points.
