## December 17, 2011

### SATELLITE COMMUNICATIONS JNTU previous years question papers

SATELLITE COMMUNICATIONS JNTU previous years question papers

Time: 3 hours Max Marks: 80
All Questions carry equal marks

1. Discuss the Performance Characteristics of different Altitude Satellites. 
2. Discuss in detail the effects of Earth Gravitational Force on Satellite. 

3. (a) Explain about 6/4 GHz Communication Subsystem in detail with neat schematics.
(b) The earth subtends an angle of 170 when viewed from geostationary orbit.What are the dimensions and gain of horn antenna that will provide global coverage at 4 GHz. [8+8]

4. (a) Discuss the uplink design.
(b) A Transponder of a Ku band satellite has linear gain of 127 dB and a nominal output power at saturation of 5W. The satellite’s 14GHz receiving antenna has a gain of 26 dB on axis and the beam covers western Europe. Calculate the power output of an uplink transmitter that gives an output power of 1W from the satellite transponder at frequency of 14.45GHz. when the earth station antenna has a gain of 50 dB and there is a 1.5 dB loss in the waveguide run between the transmitter and antenna. Assume that the atmosphere introduces a loss of 0.5dB under clear sky conditions and that the earth station is located on the -2dB contour of the satellite receiving antenna. If the rain in the path causes attenuation of 7 dB for 0.01% of the year. What output power rating is required for the transmitter to guarantee that a 1 W output can be obtained from the satellite transponder for 99.9% of the year if the uplink power control is used. [8+8]

5. (a) Define multiple access techniques? Mention the types of multiple access techniques?
(b) Give in detail about the comparisons of multiple access techniques? [4+12]

6. (a) What are the different types of antenna mounts?
(b) Suppose the receiver antenna is a parabolic dish antenna with diameter of 1.75m and is operation with a horn at 5.956GHz. Calculate the antenna operation and the gain in db. The efficiency of receiving antenna is 80%?[6+10]

7. Explain the delay and throughput Explain how optimum orbital altitude is determined?

(b) GPS codes

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