What is a satellite? What is Satellite Communication? A satellite is a moon, planet or machine that orbits a planet or star. For example, Earth is a satellite . The word "satellite" refers to a machine that is launched into space and moves around Earth or another body in space. Earth and the moon are examples of natural satellites. Thousands of artificial, or man-made, satellites orbit Earth.

1. Department of Physics
Presentation topic:
Satellite Communication
Presented By:
Umar Tabraiz

2. What is a satellite?
• A satellite is a moon, planet or machine that orbits a
planet or star. For example, Earth is a satellite .
• The word "satellite" refers to a machine that is
launched into space and moves around Earth or
another body in space.
• Earth and the moon are examples of natural
satellites. Thousands of artificial, or man-made,
satellites orbit Earth.

4. What is Satellite Communication?
• Communications satellites are artificial satellites that relay
receive signals from an earth station and then retransmits the
signal to other earth stations.
• Communications satellites are commonly used for mobile
phone signals, weather tracking, or broadcasting television
programs.

5. Two satellites which are commonly used
in satellite communication
• Passive satellites: It is just a plastic balloon having a metal
coated over it. This sphere reflects the coming microwave
signals coming from one part of the earth to other part.
• Active satellites: It basically does the work of amplifying the
microwave signals coming. In active satellites an antenna
system, transmitter, power supply and a receiver is used.
These satellites are also called as transponders.

6. What Are the Parts of a Satellite?
• Satellite transponder
• Antenna subsystems
• Solar cell and battery backup

8. • Communications satellites are used to send
and receive radio signals for television, phone
or internet communications.
• Large concave reflectors called satellite dishes
are normally used to send and receive these
signals.

10. Time delay:
• Radio waves travel at 300,000 km/s .
• This means that a signal sent to a satellite
38,000 km away takes 0.13 s to reach the
satellite and another 0.13 s for the return
signal to be received back on Earth.

11. • Only one satellite is needed to transmit television signals to a whole
country
• For example, the Optus D1 satellite was launched in 2006 to provide
television signals for the whole of Australia and New Zealand.

14. .
• What are the requirements for a satellite to be
geostationary?
• 1. Its revolutionary direction must be same as
that of the earth, i.e. from west to east.
• 2. The time period of satellite’s revolution must
be same to the time period of the rotation of
earth along its polar axis, which is equal to 24
hours.
• 3. communication is possible only if the position
of satellite becomes stationary with respect to
the position of earth.

15. Applications of satellites
• 1. Weather forecasting
• 2. Navigation
• 3. Astronomy
• 4. Satellite phone
• 5. Satellite television
• 6. Military satellite
• 7. Satellite internet
• 8. Satellite radio

16. Satellite Communication − Advantages
There are many Advantages of satellite communications such as −
• Flexibility
• Ease in installing new circuits
• Distances are easily covered and cost doesn’t matter
• Broadcasting possibilities
• Each and every corner of earth is covered
• User can control the network

17. Satellite Communication − Disadvantages
Satellite communication has the following
drawbacks −
• The initial costs such as segment and launch
costs are too high.
• Instalation into Geosynchronus orbit very
difficult