1. Satellite Communications COE 341 Term Paper

2. Groupe Members Aref Mohammad Al-Amri Ahmad Abdulrahman Al-Gahtani Ahmad Abdullah Al-Aloula

3. Topics of Presentation Applications Intro Lunching How it works Frequency Bands Satellites

4. What are Communication Satellites? A satellite is an object that orbits another large object like planet. A communication satellite is a staion in space that is used for telecommuncation, radio and television signals. The first satellite with radio transmitter was in 1957.

5. Geostationary orbits What are them? Geostationary orbits is fixed position to an earth-based observer. When was the first use? The first truly geostationary sateliite was the SYNCOM3 in 1964. Why they are important in communications? - The antennas in the ground don’t need equipment to track the satellite. - Lower cost & complixity. Disadvantages? - Not always suitable for providing services at high latitudes. - Molniya satellite was introduced as a solution.

6. Lunching Satellites How does a satellite stay in it’s orbit?

7. Frequency Bands Three common bands: 1)C-Band. 2)KU-Band. 3)KA-Band. Most common are C-Band & KU-Band. C-Band occupy 4 to 8 GHz frequency: - Low frequency. - Large antenna (2-3 meters). KU-Band occupy 11 to 17 GHz: - Large frequency. - Small antenna (18-inches!)

8. How Does a Satellite Work? Consider the light bulb example:

9. Applications Telephony - Fixed points Satellite> earth station> fixed points. Televesion & Radio - e.g. Direct broadcast satellite (DBS) & Fixed service satellite (FFS). Mobile satellite technology - Special antenna called mobile satellite antenna. - No matter where or how this antenna is mounted on.

10. Applications Amateur radio - Access to OSCAR satellite. - Low earth orbits. Internet - High Speed. - Useful for far away places. Military - Uses geostationary satellites. - Example: The Defense Satellite Communications System (DSCS).

11. Disadvantages The antenna noise due to energy - Unwanted radiation sources (stars – galaxies - …etc). - Worsen S/N ratio. Atmosphere behaves as a resistive medium - Supplies noise power to the antenna. Meteors - Have to be programmed to avoid any rock or any harmful thing. - Rules of orbits. Expensive - only for governments or large organizations.

12. In Conclusion Satellites remain the best utilization used for communications due to their speed and other advantages mentioned in this presentation.