How do the Sirius radio satelites stay over the USA?

Question

If they are in orbit, don't they go all around the world? If they do, how come I get reception 24/7?

Answer 1

Contrary to what others have said, a single Sirius satellite is not visible 24 hours a day. Each satellite is visible about 16 hours a day. With three satellites, at least one is always visible to the US and Canada.

Sirius satellites are in an inclinced, elliptical orbit to provide service for both Canada and the US. They do happen to be geosynchronous (it takes them the same amount of time to orbit the Earth as it takes for the Earth to rotate in a day). The inclined orbit means the satellite will reach a more northerly latitude to provide better service to Canada (it also means the satellte reaches a more southerly latitude when the satellites out of view). In an elliptical orbit, a satellite spends most of its time at apogee. Positioning of apogee allows the satellite to spend most of its time visible to both Canada and the US.

XM radio uses your more traditional geosynchronous satellites. They orbit along the equator and maintain the same position relative to the surface of the Earth. Being positioned on the equator also means people in northerly latitudes will not receive as good a signal, since the satellite appears to be close to the horizon.

Answer 2

they are positioned 26200 miles overhead

It is called geosynchronous orbit because the speed at which they orbit the Earth is the same as the Earth's rotational speed.

IE, they orbit once per day, so they appear to be in the same place all the time...or they appear stationary.

The Satellites only have to broadcast to one part (North America) of the world at a time, not the entire world.

if the broad cast is to be globally simulcast, they would need 3 or more satellites working in concert.

(Melissa: the only thing worse than a condescending attitude is a condescending attitude from someone who doesn't know what they are talking about)

Answer 3

The satellite has a geostationary orbit. That means that it orbits the earth at the same speed that the earth is spinning. The speed of the satellite is dependent of the height, so you just have to have the right altitude.
Geostationary satellites is not actually over USA. For this to work, they have to be over the equator and this is why satellite dishes point south.

Answer 4

While in your quest to find the answer to this question, consider this: Do you not also get reception 24/7 on satellite TV? Same concept. They do go all around the world, but the signal strength is powerful enough to connect with the towers at all times, therefore providing you with reception 24/7. That's my logical answer to in illogical question.

Answer 5

They are in synchronous orbit which means they stay over the same point on Earth.

Answer 6

Check this out real time satellite tracking from NASA

http://science.nasa.gov/realtime/jtrack/Musicsats.html

Answer 7

zero gravity

Answer 8

rubberbands

Answer 9

reflectors