Satellite Radio Channels

A communication  satellite links two or more  earth  microwave transmitter receiver, know  as ground  stations. The satellite receives transmission on one frequency  band,

Regenerates the signal  a repeater and transmits the signal  on another  frequency. Satellites can provide  transmission rates in the gigabits per second  range. Two  types  of satellites are used in communication  geostationary satellites and low altitude satellites.

Geostationary satellite permanently remain above  the same spot  on earth. This  stationary  presence is achieved by placing he satellite in orbit at 36,000kilometers above earth surface. This  huge distance from ground station through satellite back to ground stations introduces a substantial signal propagation  delay  of 250 milliseconds. Nevertheless  satellite links which  can operate at  the  speeds of hundreds of Mbps are  often  used in telephone  networks  and is  the backbone  of the internet.

Low  altitude  satellites are placed much  closer to earth and do  not remain  permanently above one spot on earth. They rotate around  earth  just as the moon  does.

 To  provide continuous  coverage to an area many  satellites need to be placed orbit. Low  altitude satellite technology may be used  be used for internet access sometimes in the future.