How Stuff Works : A Satellite

As it all starts on 4 Oct 1957 when First Manmade Satellite Sputnik-1 set into Earth orbit ever since then now there is approximately 2800 Manmade Satellite Orbiting the earth for many useful purposes.

Without Satellites, we aren't able to communicate with each other, does not watch our favorite shows, many social networking companies do not even exist, rising problems for farmers, do not predict the weather and terrorism.
But how many of know how this stuff works from Outer Space?

so let's explore the world of satellites...

this process starts on Earth, the installed transmission stations on earth sending and receiving high strength signals from a satellite.
The Area which gets the useful strengths of signals from the satellite on Earth known as satellite footprints. the signals sent from earth stations to the satellite are called uplinks and the signals receiving by earth stations from a satellite are called downlinks as in fig 1.1.

fig 1.1

What are "Bands"?

Bands are the frequency spectrums capture and sent by satellites on Earth.
There are 3 most commonly Bands use by satellites:
1. C-band: The Frequency range of this transmission band is 4GHz to 8GHz. This frequency range is comparatively lower than other bands so large diameter antenna(2-3m approx.) is used for receiving signals on earth like in fig 1.2.

fig 1.2

2. Ku-band: The  Transmission frequency spectrum of this type of Satellite is in between 11Ghz to 17GHz. Due high-frequency range it requires small antenna as 18inches in diameter to receive signals on earth.
This is used in our houses as a dish antenna like in fig 1.3.

fig 1.3

3. Ka-band: The  Transmission frequency spectrum of this type of  Satellite is in between 20Ghz to 30GHz. This frequency band is largest of all so it requires a few inches diameter of an antenna to receive signals like in fig 1.4. 

fig 1.4

Now let's know about the types of  orbits of the satellite:

1. Geosynchronous Earth Orbit(GEO) Satellite.
In 1945, Arthur C.Clarke suggested this Orbit is Best for Communication  Satellites. So, our large numbers of satellites are orbiting in this orbit 22,238miles above the earth surface. Period of rotation around the earth is exactly 24 hours. so they look stationary from Earth surface that's why most antenna dishes did not need to move once they are fixed. It requires 0.25 sec for transmission of a signal.

2. Medium Earth Orbit(MEO) Satellite: MEO satellite set above 8,000 miles above the surface. Due to shorter distance from Earth, it sends Strong signals and also requires light weight material for receiving signals and save material cost. It requires 0.1 sec to receive and send signals back on Earth.

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