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1. Satellite Communication

2. Content What is Satellite? What is Satellite Communication?

3. What is Satellite A Satellite is a solid object which revolves around some heavenly body due to the effect of gravitational forces which are mutual in nature . COMMUNICATION SATELLITE: A communication satellite  is an artificial  satellite that act as a radio relay station in orbit above the earth that receives, amplifies, and redirects analog and digital signals carried on a specific radio frequency. It act as a repeater in long distance communication path.

4. Types of Satellite Natural Satellite: e.g . moon Artificial Satellite : e .g . Aryabhata , INSAT .. Active Satellite Passive Satellite

5. ACTIVE SATELLITE It is a functioning satellite that receives and transmits or retransmits radio-communication signals to or from a base station . They have more complicated structures having a processing equipment called Transponder which is very vital  for functioning of the satellite. These transponders serve dual purpose i.e. provides amplification of the incoming and performs the frequency translation of the incoming signal to avoid interference between the incoming and  outgoing signals .

6. PASSIVE SATELLITE Passive satellites are relay stations in space. It simply reflects light or radio waves transmitted from one ground terminal to another without amplification or retransmission

7. What is Satellite Communication? Satellite communication is simply the communication of the satellite in space with large number of earth stations on the ground. A Communication Satellite can be looked upon as a large microwave repeater .

8. Users are connected to the earth station via some telephone switch or some dedicated link. They generate baseband signals, which is processed at the earth station and then transmitted to the satellite through dish antennas. The satellite receives the uplink frequency and the transponder present inside the satellite does the  processing function and frequency down conversion and then transmit the downlink signal at different frequency . The earth station then receives the signal from the satellite through parabolic dish antenna and processes it to get back the baseband signal. This baseband signal is then transmitted   to the  respective user via  dedicated link or other terrestrial system

9. Users are connected to the earth station via sometelephone switch or some dedicated link. Theygenerate baseband signals, which is processed atthe earth station and then transmitted to thesatellite through dish antennas. The satellitereceives the uplink frequency and the transponderpresent inside the satellite does the processingfunction and frequency down conversion and thentransmit the downlink signal at differentfrequency. The earth station then receives thesignal from the satellite through parabolic dishantenna and processes it to get back thebaseband signal. This baseband signal is thentransmitted to the respective user via dedicatedlink or other terrestrial system .          AD   Downlink   Uplink            AD   Long distance communication beyond 10  – 20MHz in three modes failed:-Ground wave due to conduction lossesSpace wave due to limited line of sightSky wave due to penetration of the ionosphereby the higher frequencies beyond criticalfrequency.And thus, there came the need of satellitecommunication.We have seen that the waves of freq.> 30MHz cannot propagate by conventional modes due topenetration of frequencies beyond 30MHzthrough ionosphere.                     AD   A single satellite can provide coverage to over 30% of Earth’s surface and thus was adopted for long distance communication.Communication links could be setup through out the entire world using satellites. This can’t be done with other modes of communicationdue to some severe limitations. It is often theonly solution for some isolated areas.And a new concept of communication, thecommunication through a Satelliterevolutionized communication technology.          AD   Frequency Band Range L-Band 1 to 1.5 GHzS-Band 1 to 3 GHzC-Band 3 to 8 GHzX-Band 8 to 12GHzKu-Band 10 to 18 GHzKa-Band 18 to 22 GHz                   AD   FREQUENCY BAND UPLINK DOWNLINK C-Band 6.00GHz 4.00GHzX-Band 8.00GHz 7.00GHzKu-Band 14.00GHz 11.00GHzKa-Band 30.00GHz 20.00GHz          AD   C-Band Adv. : Broad Footprint, little rain fadeDisadv. : Weak signals, interference, large antenna sizesand amplifiers Ku-Band Adv. : Focused Foot prints, no terrestrial interference smallantenna and amplifierDisadv. : Interference to rain. Ka-Band Adv. : Focused Foot prints, large unused bandwidthsDisadv. : Interference to rain.          AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD AD Reward Your Curiosity Everything you want to read. Anytime. Anywhere. Any device. No Commitment. Cancel anytime.          Share this document Share or Embed Document Sharing Options Share on Facebook, opens a new window Share on Twitter, opens a new window Share on LinkedIn, opens a new window Share with Email, opens mail client Copy link You might also like Satellite Communication - Lecture Notes, Study Material and Important Questions, Answers          Document6 pages Satellite Communication - Lecture Notes, Study Material and Important Questions, Answers M.V. TV 100% (1) Mobile and Wireless Communication Complete Lecture Notes #1          Document22 pages Mobile and Wireless Communication Complete Lecture Notes #1 Student Lecture Notes 100% (3) EC-6004 Satellite Communication Question Bank          Document30 pages EC-6004 Satellite Communication Question Bank Raja Pirian 57% (7) Magazines Podcasts Sheet music Unit 1-Satellite Communication          Document100 pages Unit 1-Satellite Communication venugopal No ratings yet Satellite Subsystems          Document43 pages Satellite Subsystems Moitreya Adhikary 100% (5) Opc Full Notes          Document103 pages Opc Full Notes anil kumar 75% (4) A Beginner's Guide to Ham Radio          From Everand A Beginner's Guide to Ham Radio George Freeman No ratings yet Adaptive Modulation and Coding          Document29 pages Adaptive Modulation and Coding Anamika Yadav No ratings yet Satellite Communication Notes          Document5 pages Satellite Communication Notes shahidaffan No ratings yet Presentation Satellite Communication          Document26 pages Presentation Satellite Communication Shivam Tomar No ratings yet Sattelite Communication          Document31 pages Sattelite Communication Sreekanth Enduru No ratings yet A Brief History of Satellite Communication          Document52 pages A Brief History of Satellite Communication idrishshaik No ratings yet Related titles Diagram Uplink Downlink

10. Why Satellite Communication? Long distance communication beyond  10-20MHz in three modes failed:-Ground wave due to conduction losses Space wave due to limited line of sight Sky wave due to penetration of the ionosphere by the higher frequencies beyond critical frequency. And thus, there came the need of satellite communication. We have seen that the waves of freq.> 30MHz cannot propagate by conventional modes due to penetration of frequencies beyond 30MHzthrough ionosphere.  

11. A single satellite can provide coverage to over30 % of Earth’s surface and thus was adopted for long distance communication.Communication links could be setup through out the entire world using satellites. This  can’t be done with other modes of communication due to some severe limitations. It is often the only solution for some isolated areas . And a new concept of communication, the communication through a Satellite revolutionized communication technology.

12. Frequency Band Used InSatellite Communication

13. Downlink frequency in different band

14. Advantages and Disadvantages In Different Bands. C-Band Adv. : Broad Footprint, little rain fade. Disadv . : Weak signals, interference, large antenna  sizes and amplifiers Ku-Band Adv. : Focused Foot prints, no terrestrial interference small antenna and amplifier. Disadv . : Interference to rain. Ka -Band Adv. : Focused Foot prints, large  unused bandwidths Disadv . : Interference to rain.

15. Components Of Satellite System Space Segment 1 . The Satellite 2 . Tracking, Telemetry and Telecommand The Ground Segment 1 . Earth Stations

16. Ground segment Ground segment is basically consist of  an earth station . An earth station provides a complete uplink and downlink chain for the signal. It transmits and receives the signal to and from the satellite . It is also consist of an antenna. Since the user baseband signal cannot be transmitted directly, it is also consist of amplifiers , modulators and demodulators , frequency up- and down- converters.

17. Satellite Earth Station Uplink/Downlink Chain

18. Working

19. The user generates the signal to betransmitted known as baseband signal. Thisbaseband signal is consist of video(5MHz),2audio subcarriers(5.5MHz and 5.75MHz) andenergy dispersal signal(25 MHz). Aftermodulation (70 MHz) and up conversion(6GHz),the carrier is amplified and uplinkedthrough solid parabolic dish antenna(PDA).Downlink signal can be received through  samePDA using trans-receive filter (TRF) and lownoise amplifier(LNA). After down conversion to70 MHz it is demodulated to get audio andvideo signal.

20. Antenna Parabolic dish antenna Diameter - gain (as a function of frequency ) Noise - temperature(as a function of elevation ) Cross- polarisation isolation Wind resistance Temperature variations tolerance Tracking...

21. Types of Antenna Prime Focus Antenna Single Reflector Antenna. Feed horn is placed at the Focal point of the Reflector. Antenna Electronics are placed on Feed. More susceptible to Interference from Low elevation sources. More Blockage because feed . Antenna Efficiency is in the range of 60 %. Low Cost Antenna. Primarily Used for Receive only applications

22. Cassagrain Antenna Main reflector is Parabolic. Sub-Reflector is hyperboloid and placed at Prime Focus Feed is Corrugated Horn and is placed at Center of the Main Reflectors . The paraboloid converges towards the Sub Reflector ( prime focus ), which is then reflected by Sub-Reflector to form a Spherical Wave converging on the Feed.

23. Gregarion Antenna Main reflector is Parabolic Sub-Reflector is Parabolic and placed at Prime Focus Feed is Corrugated Horn and is placed at Center of the Main Reflectors. The paraboloid converges towards the Sub Reflector ( prime focus ), which is then reflected by Sub-Reflector to form a Spherical Wave converging on the Feed.