What is satelite communication?

Answer 1

A satellite that's designed to be used for communications carries a radio repeater ... a radio receiver, plus a transmitter that re-transmits everything the receiver hears. Two places on earth that can't communicate by radio because there's too much stuff between them ... like trees, buildings, mountains, or the spherical bulge of the earth ... may still be able to hook up if they can both see the satellite. Both of them can point their antennas at the satellite, transmit toward it, and let it "repeat" their transmissions back to earth. Then they can talk to each other. Of course, the satellite is so far away that it takes noticeable time for the signals to follow this route ... it's a little more than 1/4 second just for the radio waves to travel end-to-end, each way through a geostationary satellite. That's the reason that conversation is often so difficult on an international or even a domestic satellite telephone circuit.

Answer 2

Most VHF and UHF radio transmissions travel in "line of sight"; if you can't see it, you can't communicate with it. So TV stations build taller and taller and taller antenna towers to lengthen the line of sight.

What if your antenna was 23,000 MILES high? You could transmit to a third of the world; with three such satellites, you could talk to the ENTIRE world at once. A Science Fiction author named Arthur C. Clarke proposed such an idea, and published it with complete technical specifications. He didn't think that we would ever be able to do it, so he wrote it as a science fiction story - but never patented the idea.

15 years later, the sky was FILLED with satellites in Clarke's orbits.