EC-603-C Satellite Communication - Jun 2025 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aWhat is Frequency Allocation? List and briefly describe the main frequency bands used in satellite communication.
   How to answer

   • Define frequency allocation and ITU role
   • List main bands: L, S, C, X, Ku, Ka, etc. with frequency ranges
   • Brief use of each band in satellite communication
   • Uplink/downlink allocation example
2. 7 Marks
   bGiven a satellite in an elliptical orbit around the Earth, use Kepler's second law to explain how the satellite's speed varies at different points in its orbit.
   How to answer

   • State Kepler's second law - equal areas in equal times
   • Relate areal velocity to orbital speed
   • Explain faster at perigee, slower at apogee
   • Conservation of angular momentum reasoning
3. 7 Marks
   aDesign a sun-synchronous orbit for an Earth observation satellite. Calculate the required orbital parameters to ensure the satellite passes over the same location on Earth at the same local solar time each day.
   How to answer

   • Define sun-synchronous orbit and nodal precession requirement
   • Condition: precession ~0.9856 deg/day
   • Key parameters: altitude, inclination ~96-100 deg, eccentricity ~0
   • Explain same local solar time repeat
4. 7 Marks
   bWhat is a Geostationary orbit? Explain the main advantages of using a geostationary orbit for communication satellites.
   How to answer

   • Define geostationary orbit: equatorial, circular, 35786 km, 24h period
   • Fixed relative to Earth observer
   • Advantages: fixed antenna, continuous coverage, no tracking
   • Ideal for broadcast and communication
5. 7 Marks
   aDefine the limits of visibility for geostationary satellites. What factors determine the visibility limits of a geostationary satellite from a specific location on Earth?
   How to answer

   • Define visibility limits: elevation angle, Earth curvature
   • Factors: earth station latitude/longitude, minimum elevation
   • Longitude separation from sub-satellite point
   • Obstructions and atmospheric effects
6. 7 Marks
   bDefine Antenna polarization. What are the different types of antenna polarization commonly used in satellite communications?
   How to answer

   • Define antenna polarization
   • Types: linear, circular, elliptical
   • Use in satellite: frequency reuse, isolation
   • Examples of LHCP/RHCP, horizontal/vertical
7. 7 Marks
   aDiscuss the significance of the space segment in enabling global communication networks. How has it revolutionized communication systems?
   How to answer

   • Define space segment: satellites, constellations
   • Role in global coverage, relay, broadcast
   • Enabling remote and mobile connectivity
   • Revolution: GEO to LEO, broadband, DTH, GPS
8. 7 Marks
   bDiscuss the role of transponders in satellite communication. How do they facilitate the relay of signals between ground stations?
   How to answer

   • Define transponder: receiver, frequency translator, amplifier
   • Bent-pipe vs regenerative types
   • Relay process: uplink, amplification, downlink
   • Enables multi-channel communication between stations
9. 7 Marks
   aExplain the setup and functionality of a receive-only home TV system. What types of signals can be received using this system?
   How to answer

   • Block diagram: dish, feed, LNB, receiver, TV
   • Receive-only function, no transmit
   • Installation and pointing
   • Signals: TV broadcast, DTH, data
10. 7 Marks
    bExplain how EIRP is calculated and its significance in determining the coverage area and signal strength of satellite communication.
    How to answer

    • Define EIRP = Pt * Gt, formula in dBW
    • Calculation steps with losses
    • Significance for coverage contour and link budget
    • Relation to signal strength at earth station
11. 7 Marks
    aDefine System noise. Discuss the effects of system noise on the quality and reliability of satellite communication links.
    How to answer

    • Define system noise temperature and noise figure
    • Sources: antenna, receiver, cosmic
    • Effect on C/N, BER, link quality
    • Impact on reliability and margin
12. 7 Marks
    bExplain how rain attenuation is quantified and its impact on the performance of satellite communication systems.
    How to answer

    • Quantification: specific attenuation dB/km, ITU models
    • Dependence on rain rate, frequency, polarization
    • Impact: fading, depolarization, reduced availability
    • Mitigation: power control, diversity, margins
13. 7 Marks
    aOutline the steps involved in installing a DBS-TV antenna. How can potential obstacles such as buildings or trees affect antenna installation?
    How to answer

    • Site survey, mounting, alignment steps
    • Azimuth/elevation setting, polarization skew
    • Cabling and receiver setup
    • Effect of blockage, shadowing, multipath
14. 7 Marks
    bConsider a scenario where a company plans to deploy a VSAT system to connect remote offices. Outline the steps involved in designing and implementing the VSAT network, including network planning, equipment selection and installation.
    How to answer

    • Requirement analysis and network planning
    • Hub vs remote equipment selection, topology
    • Frequency, link budget planning
    • Installation, testing and commissioning steps
15. 14 Marks
    Write a short note any two

    1. a)Orbit Perturbations
    2. b)Morelos and Satmex 5
    3. c)Transmission Losses
    4. d)Satellite Radio Broadcasting
    How to answer

    • Select any two topics for detailed note
    • Give definition, key principles and diagrams where relevant
    • Mention applications in satellite communication
    • Conclude with significance