Coverage of a satellite

Like ordinary radio repeaters installed on top of a mountain have greater coverage in relation to the horizon and curvature of the earth's crust, the satellites also have the artificial horizon that allows them to broad areas of coverage in the so-called line of sight radio. The polar orbiting satellites in low orbitam the Earth from varying altitudes and that generally start around 300 km and may exceed 2000 km in altitude on poles.

This orbital position, the satellite has an artificial horizon where it is seen and illuminates, in radio terms, the same area that Continental can go from Portugal to America, or cover a substantial part of Europe and Africa.