Have we ever wondered why satellite dish antenna receiver of satellite signal need not change its direction even though satellite move with speed 3 km/sec?
Because even if the satellite moves, its movements are made equal to the Earth's surface velocity. So the position will be the same relative to the surface of the Earth.
The lower the height of the orbits of satellites, the higher the speed of the satellites required to maintain orbit. Conversely, the higher the orbital height, the lower the required satellite speed.
From these relationships, an orbital height can be searched where the angular velocity of the satellite will be equal to the angular velocity of the Earth's surface. The height of the orbit is 35786 km above the earth's surface.
Orbit with an altitude of 35786 km is called geostationary orbit. The satellites placed at this altitude will have a constant position relative to the Earth's surface. The condition, the satellite must be above the equator and move in the direction of the Earth's rotation.
Because the position is constant relative to the surface of the Earth, the satellite dish satellite dish antenna only needs to be directed in a constant direction, and its direction does not need to be replaced as long as the satellite is operational and does not change position.
Since the geostationary satellites are above the equator, the receiver north of the equator needs to direct the parabolic antenna to the south. And vice versa, the receiver south of the equator needs to direct its parabolic antenna to the north.
Best Regard 
Reference :
https://en.wikipedia.org/wiki/Geosynchronous_orbit
https://en.wikipedia.org/wiki/List_of_orbits
https://en.wikipedia.org/wiki/Geostationary_orbit
