Geostationary Orbit: How Satellites Stay Fixed in the Sky
Look at any row of satellite dishes on a skyline and they all point to the same patch of sky. That is because the satellites they watch hover in a special orbit — the geostationary arc — and never seem to move.
What Is a Geostationary Orbit?
A satellite about 35,786 km above the equator, travelling in the same direction as the Earth spins, orbits once every 24 hours. From the ground, it appears to hang fixed in the sky. That is why your dish can be bolted down and pointed at a fixed spot.
Why the Arc Matters
Geostationary satellites all sit over the equator, arranged along an arc from east to west. In Europe, that arc runs roughly from 30°W in the west to 60°E in the east. A motorised dish swings along this arc to watch different satellites.
Why Your Dish Points South
In the northern hemisphere, the geostationary arc lies to the south. That is why satellite dishes face south — and why a north-facing wall is useless.
Latitude and Elevation
The higher your latitude, the lower the satellite sits in the sky. In northern Scotland, geostationary satellites are barely above the horizon; in southern Europe, they ride high. That is why dishes in the north need bigger antennas and more clearance.
Geostationary orbit is the trick that makes fixed dishes possible. Without it, every house would need a tracking antenna.
