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A communications' satellite is essentially a microwave relay in the sky, operating at 22,300 miles above the earth's equator. It receives microwave signals in a given frequency and retransmits them at a different frequency. Satellites provide an efficient means of reaching isolated places on the earth and are considerably less expensive than terrestrial communication links for select applications.
Satellites are a versatile form of wireless communication. What distinguishes communication satellites from other forms of wireless communication (cellular, paging etc.) is its high orbital position and movement.
Geosynchronous Orbit (GSO)
Satellites that operate at 22,300 miles above the earth's equator are said to operate in geosynchronous orbit. The satellite holds its position relative to the earth's equator and rotates at the speed of the earth.
The term Fixed Satellite Services (FSS) is sometimes used to describe
satellites that operate in the GSO. Today, there are over 200 satellites that operate in the GSO. Satellites that operate in the GSO can provide 24 hours per day service which is essential for broadcasting and telephony.
The earth station functions as a receiving antenna; that is, it receives the satellite fed signal which can be voice, video or data communications.
Suggested Video Presentations
How do Satellites Work? Available at:
The Principles of Satellite Television Available at: