Department of Electronics &Communication
Subject- Satellite Communication
Time :30 min.
Note:-Attempt any Five questions. Question 1 is compulsory.
Semester-7th
MM.60
Q.1 (a) What are the Orbital Elements of Satellite Communication? Explain each with
suitable diagram.
(10*2)
(b) For an earth station latitude and longitude are 350N and 1000W. The GEO satellite
location is 900W. Find the azimuth & elevation angle for the earth station. The mean
radius of earth is 6371 km and orbital radius is 42164 km. Find also the range.
Q.2 (a)What are the Kepler’s three laws of planetary motion? Give the mathematical
formulation
of Kepler’s third law of planetary motion.
(5*2)
(b) A satellite in an elliptical orbit around the earth has an apogee of 39,152 km and a
perigee of 500 km. What is the orbital period of the satellite? Give answer in hours.
Assume the avg. earth radius is 6378.137 km and Kepler’s constant has the value 3.9868
x105km3/s2.
Q.3 (a) What are the orbital effects and how they affect the satellite system performance?
(5*2)
(b) List various advantages & disadvantages of satellite communication?
Q.4 (a)Explain TTC& M in detail with suitable diagram.
(5*2)
(b) The EIRP of a 240 W transponder is 57 dBW. Calculate the approximate gain of the
antenna. If the transponder is switched to 120 W, calculate the new EIRP assuming that
same antenna is used.
Q.5 (a) A satellite TV signal occupies the full 36 MHz transponder bandwidth and is desired
to provide a C/N ratio of 22dB at the earth station. If the downlink frequency is 4 GHz
and the other losses amount to 3.4 dB what must be the G/T ratio of the earth station if
EIRP is 37 dBW. The path length is 40000 km.
(5*2)
(b) Write a short note on satellite antenna.
Q.6 (a) Thermal Noise in an earth station receiver results in a (C/N)dn ratio of 20 dB. A signal
is received from a bent pipe transponder with a (C/N)up ratio of 20 dB. What is the value
of overall (C/N)o at the earth station? If the transponder introduces intermodulation
products with (C/I) ratio of 24 dB, what is the overall (C/N)0 ratio at the receiving earth
station. (5*2)
(b) Write a short note on satellite uplink design.