How does DS1's communications system work?
Considering that music radio stations may use 50 kilowatts (50,000 watts) to broadcast over 100 kilometers, it's difficult to believe that DS1 can communicate over tens of billions of kilometers with under 100 watts. That's 1/500th the amount of energy used by a radio station to send a signal millions of times farther!
There are two main differences between the systems used by radio stations on Earth and those used in satellite communications. First, satellites use higher frequencies that are more powerful than other radio waves and allow them to concentrate all available power into a narrow beam. This helps to reduce bandwidth, which leaves more bandwidth over to send more communications. Secondly, satellites carefully direct this narrow beam in one direction (right at the exact spot where it knows the antenna will be) while radio stations broadcast in all directions.
The antennae on Earth that receive the signals help as well. They are much more sensitive than, say, a car antenna, and have very complex computer programs that separate out the satellite's signal from other radio noise. The antennae are also very large---and their dish shape helps collect the signal too.
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What kind of data is DS1 sending back?
How are frequency and wavelength related?
More about radio waves and electromagnetic radiation.
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What radio frequency does DS1 use for communications?
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