1. Satellite communication
4th year

2. Contents… Communication Types of communication Frequency spectrum
Basics of satellite communication
Frequency bands
Advantages and disadvantages
Major problems
Applications

3. Communication
The technique which helps to transfer information from one place /node /terminal /device to another is called communication.

4. Types Of Communication
Wired
Wireless
Mobile
(890 MHz)
Satellite
(6/4 GHz)
Remote
(10^3 Hz)

5. Frequency Spectrum

6. Basics of satellite communication
Satellite: A celestial body that orbits a planet

7. Why satellite communication?
Microwave band of frequency is used
High frequency waves travel in straight line
Earth is curved
Solution: satellite
An earth station transmits the signal up to the satellite-called the up-link and is transmitted on one frequency.
The satellite receives the signal and retransmits it on the down link which is on another frequency.

8. Using a satellite for long distance communications

9. Why not moon?
concept proved by naval research lab in Washington D.C.by using moon in 1940’s.
Surface of the moon is tough and uneven that most of the signal scatters back into space instead of bouncing back to earth.
Moon can only reflect signals. Modern communication satellites actively rebroadcast the signal back to earth.
Moon is only available for half of the day, and it keeps moving. Earth based antenna have to move to track it.

10. Frequency Bands
Name of the freq. band Range of freq. 1.) L 1-2(GHz) 2.) S 2-4(GHz) 3.) C 4-8(GHz) 4.) X 8-12(GHz) 5.) Ka 12-18(GHz) 6.) K 18-26(GHz) 7.) Ku 26-40(GHz)

11. Advantages of satellite communication
Provision of service to remote or underdeveloped area.
Transmission cost is independent of distance.
Higher bandwidth is available.
Larger coverage area than terrestrial network.
Independent from terrestrial infrastructure.

12. Disadvantages of Satellite Communication
Making and launching a satellite is a complex and costly process.
Difficulty in troubleshooting a satellite.
Larger propagation delay is found in satellite communication.

13. Major problems in satellite communication
Difficulty in designing and positioning a satellite.
Less stability (due to difficulty in alignment and direction of antenna).
Large power requirement.
Harsh climate affect transmission of signals.

14. Applications Weather forecasting VSAT(very small aperture terminal)
Communication
Military and intelligence satellite
Research and development
Observation of distant stars and other objects in space
GPS and navigation

15. Thank you