Siddaganga Institute of Technology, Tumakuru – 572 103

(An Autonomous Institution affiliated to Visvesvaraya Technological University, Belagavi)

Department of Electronics and Communication Engineering
Question Bank

Subject: Satellite communication (RECE04) Class: VII Semester

Unit 1: Overview of satellite systems, orbits

Q. No. Question Marks BL CO PO
1 State Kepler’s laws of planetary motion. Illustrate in each case with 6 L2 CO1 PO1
necessary equations their relevance in satellites orbiting the earth
2 A satellite is in an elliptical orbit with a perigee of 1,000km and an 6 L3 CO1 PO2
apogee of 4,000km. Compute the orbital period in hours, minutes
and seconds and eccentricity of the orbit, given that GM =
3.9860004418 * 105 km3/s2.
3 With the aid of a neat sketch, explain what is meant by each of the 8 L2 CO1 PO1
following: Angle of inclination; argument of perigee; ascending and
descending nodes, Mean anomaly and true anomaly
4 For a satellite of a NASA ,for a certain epoch gives eccentricity as 6 L3 CO1 PO2
-3 o
9.5981x10 and the mean anomaly as 204.9779 , the mean motion
is 14.217404 rev/day. Calculate the true anomaly and magnitude of
the radius vector 5secs after epoch. The semi major axis is given by
7194.9km
5 The orbit of an earth orbiting satellite has an eccentricity of 0.15 and 6 L3 CO1 PO2
semi major axis of 9000kms. Determine i) Periodic time ii) Apogee
height iii) Perigee height. Take μ = 3.986×10 5km3/s2, earth radius
= 6371kms
6 Explain how a satellite continues to be in orbit. Derive expressions 8 L2 CO1 PO2
for i) Satellite velocity ii) Orbital period
7 A satellite is in an elliptical orbit with a perigee of 4,000km and an 6 L3 CO1 PO2
apogee of 8,000km. compute the orbital period in hours, minutes and
seconds and eccentricity of the orbit, given that
GM = 3.9860004418 * 105 km3/s2
8 The orbit of an earth orbiting satellite has an eccentricity of 0.15 and 6 L3 CO1 PO2
semi major axis of 9000kms. Determine i) Periodic time ii) Apogee
height iii) Perigee height. Take µ = 3.986×105km3/s2, earth radius =
6371kms
9 With a neat sketch explain the six orbital elements to define a 6 L2 CO1 PO1
satellite orbit
10 Describe Kepler’s laws of planetary motion with necessary 6 L2 CO1 PO2
equations
11 Describe the satellite eclipse and Sun-transit outage occurrences, 6 L2 CO1 PO1
challenges they offer.
12 The semi major axis and semi minor axis of an elliptical satellite 6 L3 CO1 PO2
orbit are 20,000km and 16,000km respectively. Determine the
apogee and perigee.
13 Show that the orbital period is proportional to the cube of the semi 6 L2 CO1 PO1
major axis. Also derive the equation for the velocity of the satellite
in the orbit
14 The orbit of an earth orbiting satellite has an eccentricity of 0.2 and 6 L3 CO1 PO2
semi major axis of 9000kms. Estimate i) its Periodic time ii) Apogee
height iii) Perigee height. μ = 3.986×105km3/s2, earth radius =
6371kms
15 A satellite is moving in a circular orbit for a period of 4 L3 CO1 PO2

1day.Calculate the radius of the orbit. Take μ = 3.986×105km3/s2

16 Two satellites are moving in different orbits with same perigee but 5 L3 CO1 PO2
different apogee distances. The semi major axis of the two orbits are
16000km and 24000km.Determine the orbital period of satellite 2, if
the orbital period of satellite 1 is 600minutes.
17 Two satellites are moving in an elliptical eccentric orbit with same 5 L3 CO1 PO2
perigee but different apogees distances. Satellite 1 is having an
orbital period of 5hours and semi major axis of 20000km, while the
orbital period of satellite 2 is 2hours and 50minutes.Dettermine the
semi major axis of the satellite 2.
18 A satellite is at 322km high circular orbit. Determine (i) The orbital 6 L3 CO1 PO2
velocity in meters/sec (ii) The orbital period in minutes and (iii) The
orbital angular velocity in radians/sec
19 Describe the effect of orbital perturbations on the satellite orbits. 6 L2 CO1 PO2

20 Explain what is meant by apogee height and perigee height. The 6 L3 CO1 PO2
Cosmos 1675 satellite has an apogee height of 39,342km and a
perigee height of 613km.Determine the semi major axis and the
eccentricity of its orbit. Assume mean earth radius as 6371km.

Unit 2: Geostationary orbit

Q. No. Question Marks BL CO PO
1 How look angles are determined for a communication satellite? An earth 8 L3 CO2 PO2
station is located at latitude 35°N and longitude 65°E. Calculate the
antenna-look angles for a satellite at 19°E
2 What is the importance of polar mount antenna? How the tilt angle is 6 L3 CO2 PO2
estimated for a polar mount antenna?
3 Determine the angle of tilt for a polar mount used with a earth 6 L3 CO2 PO2
o
station at latitude 49 N.Assume spherical mean earth radius of
6371km and earth station altitude of 42,164km
4 What is meant by look angles in satellite communication? Illustrate 8 L3 CO2 PO2
the computation of look angles for an earth station to be set up at
SIT-Tumkur (13.3°N, 77.1°E) for a satellite at 83°E.
5 What is meant by polar mount antenna? What are its advantages? 6 L2 CO2 PO2

6 Describe the satellite eclipse and Sun-transit outage occurrences, 6 L2 CO2 PO1
challenges they offer
7 An earth station in England needs to calculate the look angle to a 8 L3 CO2 PO2
GEO satellite in the Indian ocean operated by Intelsat.The earth
station latitude 12°S and longitude 52°W. Calculate the antenna-look
angles for a satellite at 70°W. Sketch the longitude and latitude
diagram and indicate the coordinates
8 Evaluate the angle of tilt for a polar mount used with an earth station at 6 L3 CO2 PO2
o
latitude 13.3 N.Assume a spherical earth of mean radius 6371km and earth
station altitude is 42,164 km
9 Estimate the angle of tilt for a dish antenna to be fixed at Tumkur 6 L3 CO2 PO2
which has latitude Le=13.3oN and Longitude le=77.1oE. Take
rs=42164km and re=6371km
10 An earth station is located at latitude 35°N and longitude 65°E. 8 L3 CO2 PO2
Calculate the antenna-look angles for a satellite at 19°E
11 Determine the limits of visibility for an earth station situated at 6 L3 CO2 PO2
latitude 12.97° N and longitude 77.59° E for Geo-stationary satellite.
Assume a minimum angle of elevation of 5°, Radius of earth = 6371
km
12 Calculate the look angles for as satellites at 83°E, an earth station 8 L3 CO2 PO2
located at TUMKUR latitude of 13.3°N and longitude of 77.1°E.
13 An earth station is located at a latitude 30o S and longitude 130oE. 8 L3 CO2 PO2
Calculate the antenna look angles for a satellite at 156o E
14 An earth station is located at a latitude 12o S and longitude 52oW. 8 L3 CO2 PO2
Calculate the antenna look angles for a satellite at 70o W.
15 An earth station is located at a latitude 35o N and longitude 100oW. 8 L2 CO2 PO2
Calculate the antenna look angles for a satellite at 67o W.
16 Explain what is meant by the Geostationary orbit? How do the 4 L2 CO2 PO1
Geostationary orbit and Geosynchronous orbit differ?
17 What is the significance of Hofmann transfer orbit? Describe with a 6 L2 CO2 PO1
necessary sketch the launching of the orbits.
18 Explain what is meant by earth eclipse of an earth –orbiting satellite. 6 L2 CO2 PO2
Why is it preferable to operate with a satellite positioned west, rather
than east of earth station longitude?

Unit 3: Radio wave propagation, Space Link

Q. No. Question Marks BL CO PO
1 What are the Propagation Impairments that pose serious concern for 8 L2 CO3 PO1
satellite communications? Mention the remedies commonly used.
2 How atmospheric and Ionospheric losses contribute to link in 6 L2 CO3 PO1
satellite communication?
3 Evaluate the rain attenuation for horizontal, vertical and circular 10 L3 CO3 PO2
polarizations with a frequency of 12GHz. The rain attenuation is
exceeded 0.01% of time in any year, for a point rain rate of
10mm/hr. The earth station altitude is 600 meter, and the antenna
elevation angle of 50°. The rain height is 3km and ah=0.0188,
bh=1.217, av=0.168, bv=1.2.How do you infer the results?.
4 Calculate the rain attenuation for a frequency of 18GHz for circular 6 L3 CO3 PO2
polarization. The rain height 2 km, a rain rate of 10mm/h is
exceeded for 0.001percent of the year. The earth station altitude
600m and antenna elevation angle of 35°. (ah=0.0751, av=0.0691,
bh=1.099, bv=1.065)
5 Compare the specific attenuations for vertical and horizontal 6 L3 CO3 PO2
polarizations at a frequency of 4GHz and a point rain rate of 8mm /
H which is exceeded for 0.01 percent of the year.Take
ah=0.00065,bh=1.121, av=0.000591,bv=1.075
6 Explain how atmospheric and Ionospheric losses contribute to link 6 L2 CO3 PO1
in satellite communication?
7 Explain what is meant by effective path length in connection with 6 L2 CO3 PO1
rain attenuation.
8 Given that for a satellite transmission El=22o , R0.01=15mm/h, 6 L3 CO3 PO2
ho=600m,hR=1500m, and horizontal polarization is used, calculate
the rain attenuation for a signal frequency of 14GHz.
9 A 5Hz receiver has Tin = 25K, TRF=50K, TIF=1100K, TM = 400K, 6 L3 CO3 PO2
GRF = 50 dB, GM= -5dB and a section of loss waveguide of 1.5 dB
is running between antenna and the RF amplifier. Calculate system
noise temperature at the input of waveguide
10 Calculate the gain in decibels of a 3m parabolic antenna at a frequency 4 L3 CO3 PO2
of 12GHz. Assume an aperture efficiency of 0.55
11 With relevant expressions, mention the significance of the 10 L2 CO3 PO1
following:
i) Antenna noise temperature.
ii) Amplifier noise temperature.
iii) System noise temperature.
iv) Atmospheric losses.
v) Ionospheric losses
12 Calculate the approximate value of atmospheric attenuation for a 6 L3 CO3 PO2
satellite transmission at 14 GHz, for which the angle of elevation of
the earth-station antenna is 15°.
13 Develop an expression for [C/N]D considering various factors for a 4 L3 CO3 PO2
satellite link
14 Given that for a satellite transmission El = 22°, R0.01 = 15 mm/h, 6 L3 CO3 PO2
h0 = 600 m, hR= 1500 m, and horizontal polarization is used,
calculate the rain attenuation for a signal frequency of 14 GHz
15 For a satellite circuit [C/N0]U = 101.5dBHz and [C/N0]D = 93.2dBHz. 4 L3 CO3 PO2
Calculate the combined [C/N0]Total.
16 Find free space path loss for an uplink operating frequency at 6GHz 4 L3 CO3 PO2
with a distance R=42000km.If the earth station EIRP is 120dbW,
What will be the received power in dBW. Assume Gr=0.
17 The range between a ground station and a satellite is 42,000km.Calculate 4 L3 CO3 PO2
the path loss at a frequency of 6GHz.
18 In a link budget calculation at 12GHz,free space loss is equal to 4 L3 CO3 PO2
206db,antenna pointing loss is 1db,and the atmospheric attenuation is
2db.The receiver (G/T) is 19.5db/k.,the receiver feeder losses are 1db and
EIRP is 48dBW. Calculate the noise spectral density ratio.
19 A satellite TV signal occupies the full transponder bandwidth of 5 L3 CO3 PO2
36MHz and it must provide a C/N ratio at the destination earth
station of 22db.Given that total transmission losses are 200db and
earth station G/T ratio is 31db/k, Calculate the satellite EIRP
required.
20 What is meant by carrier-to-noise ratio? At the input to a receiver the 6 L3 CO3 PO2
received carrier power is 400 pW and the system noise temperature
is 450K. Given that the bandwidth is 36 MHz, Estimate the values of
carrier-to-noise ratio in dBHz and decibels
21 The [C/N] values for a satellite circuit are uplink 25 dB, downlink 4 L3 CO3 PO2
15 dB. Obtain the overall [C/N] value.
22 For a satellite circuit, the individual link carrier to noise spectral density L2 CO3 PO2
ratios are Uplink 100dBHz, downlink 87dBHz.Calculate the combined
C/N ratio.
23 Develop an equation for combined uplink and downlink C/N Ratio 6 L2 CO3 PO1
with relevant diagrams.
24 Explain how the feeder losses and antenna misalignment losses 6 L2 CO3 PO1
contribute for the losses in satellite system
25 What is meant by carrier-to-noise ratio? Derive an expression for the 6 L2 CO3 PO1
carrier to noise ratio at the receiver input in satellite link.
Unit 4: Space segment and earth segment
Q. No. Question Marks BL CO PO
1 Why station keeping is necessary for a satellite? What are the ways of 6 L2 CO4 PO1
station keeping? Explain
2 Describe TT&C subsystem with relevant block diagram. 8 L2 CO4 PO1

3 With a block diagram, explain indoor and outdoor unit of direct 8 L2 CO4 PO1
broadcasting satellite TV
4 With a neat diagram, describe MATV system used to provide 8 L2 CO4 PO2
reception of satellite channels to small group of users
5 Briefly describe the three-axis method of satellite stabilization. 6 L2 CO4 PO1

6 What is a transponder? Analyze along with a relevant sketch how a 6 L2 CO4 PO1
frequency reuse technique accommodates more number of channels
in c-band communication
7 Explain what is meant by thermal control and why this is necessary 6 L2 CO4 PO1
in a satellite
8 It is required to watch a Live TV programme .Suggest an outdoor 8 L3 CO4 PO2
unit and indoor unit of a Ku-band Direct broadcast TV receiver and
describe the salient features of each stage of the system
9 What is a transponder? Analyze along with a relevant sketch how a 6 L3 CO4 PO2
frequency reuse technique accommodates more number of channels
in c-band communication
10 A DBS TV/FM channels are to be used to provide reception to a 8 L3 CO4 PO2
small group of users. Suggest a Master antenna (MATV) system
which can satisfy these requirements and describe each stage of the
system
11 With the help of a neat diagram, explain the functioning of 8 L2 CO4 PO1
Transmit-Receive earth station used for telephone traffic in a
satellite communication.
12 What is meant by Altitude control? Describe three axes method of 8 L2 CO4 PO1
altitude control and spin stabilization.
13 Explain why some satellites employ cylindrical solar arrays whereas 6 L2 CO4 PO1
some other employ solar –sail arrays for production of power supply
14 Describe with a neat block diagram, a satellite wideband receiver. 6 L2 CO4 PO1

15 Explain what is meant by frequency reuse and describe briefly two 6 L2 CO4 PO1
methods by which this can be achieved.
16 Describe and compare MATV and CATV systems. 8 L2 CO4 PO1

Unit 5: Interference and satellite access

Q. No. Question Marks BL CO PO
1 How interference is originated in satellite networks? Describe the 8 L2 CO5 PO1
modes of interference in satellite communication networks.
2 Distinguish between preassigned and demand assigned traffic in 8 L2 CO5 PO1
relation to a satellite communication networks
3 What is meant by pre-assigned FDMA? Illustrate with necessary 8 L2 CO5 PO1
 sketches how channel allocation is done in preassigned FDMA
4 An FM/ TV carrier is specified as having a modulation index of 4 L3 CO5 PO2
2.571 and a top modulating frequency of 4.2Mhz.Calculate the
protection ratio required to give a quality impairment factor of (i) 4.2
and (ii) 4.5
5 Calculate the frame efficiency for an INTELSAT frame given the 6 L3 CO5 PO2
following information:
Total frame length=120,832symbols ,
Traffic burst per frame=14
Reference bursts per frame=2
guard interval=103symbols
CBR=176,UW=24,TTY=8,SC=8,VOW=32,CDC=8 symbols
6 Along with the common signaling channel scheme (CSC) , explain 6 L2 CO5 PO1
the spade system in satellite communication
7 Compare the increase in interference levels expected when a satellite 4 L3 CO5 PO2
orbital spacing is reduced from 6° to 4° for an earth station antenna
side lobe pattern of (i) 32 – 25log θ dB and (ii) 29 – 25log θ dB
8 With power density curves, explain the pass band interference. 6 L2 CO5 PO1

9 Illustrate common signaling channel (CSC) for a spade system. 6 L2 CO5 PO1

10 What are the possible interference modes between satellite circuits 8 L2 CO4 PO1
and a terrestrial station? Explain with a relevant diagram.
11 Explain what is meant by protection ratio. A TV/FM carrier operates 6 L3 CO5 PO2
at a modulation index of 2.619, the top modulating frequency being
4.2 MHz. Calculate the protection ratio required for quality factors
of (a) 4.2 and (b) 4.5.
12 Develop an equation for Carrier to interference ratio for uplink and 6 L2 CO5 PO1
downlink
13 Explain preassigned TDMA and Demand assigned TDMA. 8 L2 CO5 PO1

14 Station A transmits at 24dBW with an antenna gain of 54db Explain 4 L3 CO5 PO2
the significance of and station C transmits at 30dBW. The off-axis
gain is 24.47dBand the polarization discrimination is 4dB.Calculate
the [C/I] ratio on the uplink.
15 Explain with a block schematic, the significance of receiver transfer 6 L2 CO5 PO1
characteristics in estimating the signal to interference ratio in a
satellite receiver system.
16 What is meant by single entry interference? Explain why it is the 6 L2 CO5 PO1
radiation pattern of the earth station antennas, not the satellite
antennas which governs the level of interference.
17 An FDM?FM satellite circuit operates with an uplink transmitter
power of 11.9 dBW, an antenna gain of 53.5dB and a satellite
[EIRP] of 19.1dBW.The destination earth station has an antenna
gain of 50.5dB. A TV/FM interfering circuit operates with an uplink
transmit power of 28.3dBW and a satellite [EIRP] of 35 dBW.
Polarization discrimination figures are 6dB and 0dB for uplink and
downlink respectively. Given that [RTC]=60.83dB, calculate the
baseband [S/I] ratio for an antenna
18 A satellite TV/FM circuit operates with an uplink power of 6 L3 CO5 PO2
30dBW,an antenna gain of 53.5dB and a satellite [EIRP] of
34dBW.The destination has a receiver antenna gain of 44dB. An
interfering circuit has an uplink power of 11.5dBW and a satellite
[EIRP] of 15.7dBW. Given that spectral overlap is
[Q]=3.8dB,Calculate the passband [C/I] ratio. Assume polarization
discrimination figures of 4dB and 0dB for uplink and downlink
 respectively and an antenna side lobe pattern of 32-25logθ.The
satellite spacing is 2o.
19 A Satellite circuit operates with an uplink transmit power of
28.3dBW and an antenna gain of 62.5dB.A potential interfering
circuit operates with an uplink power of 26.3dBW.assuming a 4-dB
polarization discrimination and earth station sidelobe gain function
of 32-26logθ dB, calculate the[C/I] ratio at the satellite for 2 o
satellite spacing