Multiple Choice Questions and Answers on Satellite Communication
Q1. Satellite engine uses …………
a. Jet
b. Ion propulsion system
c. Liquid fuel
d. Solar jet
Answer : b
Q2. The earth area covered by a satellite radio beam is known as ……..
a. Beam width
b. Band width
c. Footprint
d. Zone
Answer : c
Q3. What kind of battery used by older satellites ?
a. Lithium
b.
c. Hydrogen
d.
Answer : c
Q4. The location of AsiaSat I.
a. 105.5˚ East
b. 151.5˚ East
c. 115.5˚ East
d. 170.5˚ East
Answer : a
Q5. To make antenna more directional, either its size must be increased or
a. the number of its feed horns must be increased
b.the frequency of its transmission must be increased
c. its effective isotropic radiated power (EIRP) must be increased
d. its footprint must be increased
Answer : b
Q6. India’s first domestic geostationary satellite 1NSAT-IA was launched on 10th April 1982 from
a. USSR
b.USA
c. UK
d. UP
Answer : b
Q7. Satellite launch sites are invariably located on Eastern seaboards to ensure that
a. launch takes place eastward
b. expenditure of propulsion fuel is reduced during plane changing
c. the satellite achieves circular orbit quickly
d. spent rocket motor and other launcher debris falls into the sea
Answer : d
Q8. The owner of a communication satellite is usually required to keep the spacecraft on station at its assigned place in the geosynchronous orbit with an accuracy of __________ degree.
a. 0.1
b. 1.0
c. 2.0
d. 0.5
Answer : a
Q9. The number of days when Earth’s shadow falls on a geosynchronous satellite is
a. 88
b. 277
c. 5
d. 10
Answer : a
Q10. A satellite signal transmitted from a satellite transponder to earth’s station is ……….
a. Uplink
b. Downlink
c. Terrestrial
d. Earthbound
Answer : b
Q11. A helical antenna is used for satellite tracking because of …………..
a. Circular polarization
b. Maneuverability
c. Beamwidth
d. Gain
Answer : a
Q12. What band does VSAT first operate?
a. L-band
b. X-band
c. C-band
d. Ku-band
Answer : c
Q13. VSAT was made available in ……..
a. 1979
b. 1981
c. 1983
d. 1977
Answer : a
Q14. ……………. collects very weak signals from a broadcast satellite
a. Helical antenna
b. Satellite dish
c. LNA
d. TWT
Answer : b
Q15. ………….is a loss of power of a satellite downlink signal due to earth’s atmosphere.
a.
b.
c. Radiation loss
d. RFI
Answer : b
Q16. …………… is considered as the unsolved problem in satellite system.
a. Coverage
b.
c. Access
d. Privacy
Answer : d
Q17. As the height of a satellite orbit gets lower, the speed of the satellite ……………
a. Increases
b. Decreases
c. Remains the same
d. None of the above
Answer : a
Q18. A satellite beam that covers almost 42.4% of the earth’s surface is called ……………
a.
b. Hemispheric beam
c. Spot beam
d. Global beam
Answer : d
Q19. A geosynchronous satellite
a. has the same period a that of the Earth
b. has a circular orbit
c. rotates in the equatorial plane
d. has all of the above
Answer : d
Q20. A transponder is a satellite equipment which
a. receives a signal from Earth station and amplifies
b. changes the frequency of the received signal
c. retransmits the received signal
d. does all of the above-mentioned functions
Answer : d
Q21. The INTELSAT-IV satellite launched in 1974 had two earth coverage antenna and two narrower-angle antennas subtending 4.5°. The signal from narrow-angle antenna was stronger than that from earth- coverage antenna by a factor of ……………
a. 17.34/4.5
b. 17.34/4.5
c. (17.34/4.5)2
d. (17.34/4.5)4
Answer : c
Q22. The angle subtended by earth at geostationary communication satellite is ………..
a. 17.34°
b. 51.4°
c. 120°
d. 60°
Answer : a
Q23. The discussing sharing of a communication satellite by many geographically dispersed Earth station, DAMA means
a. Demand-Assigned Multiple Access
b. Decibel Attenuated Microwave Access
c. Digital Analog Master Antenna
d. Dynamically-Assigned Multiple Access
Answer : a
Q24. A 20 m antenna gives a certain uplink gain at frequencies of 4/6 GHz. For getting same gain in the 20/30 GHz band, antenna size required is ……… metre.
a. 100
b. 4
c. 1
d. 10
Answer : b
Q25. Of the four INSAT-I satellites planned by India so for, only …………… has proved to be successful.
a. INSAT-IA
b. INSAT-IB
c. INSAT-IC
d. INSAT-ID
Answer : b
Q26. Radio broadcasting is a familiar example of …………….
a. space multiplexing
b. time multiplexing
c. frequency multiplexing
d. none of the above
Answer : c
Q27. As compared to 17.34° antenna, the total increase in the signal relayed by 4.5° antenna of INTELSAT-IV is ……….
a. 14.85
b. 220
c. 78
d. 3.85
Answer : b
Q28. Which one of the following statements regarding DSI is false?
a. It is a digital form of TASI
b. Though it is more efficient than TASI, it is much slower
c. A speaker has to wait (it at all) for only a few milliseconds for reallocation of channel
d. It has increased the capacity of satellite channels by a factor of 2.2 or more with out degrading speech quality
Answer : b
Q29. Which one of the following statements regarding compandor is FALSE?
a. It compresses the higher-amplitude parts of a signal before modulation and expands them back to normal again after demodulation.
b. It gives preferential treatment to the weaker parts of the signal
c. For weaker signals it gives a poor ratio of signal strength to quantizing error
d. Weaker signals, traverse more quantum steps than they would do otherwise and so quantizing error is reduced.
Answer : c
Q30. The quality of a space-link is measured in terms of the ………. ratio.
a. C/N
b. S/N
c. G/T
d. EIRP
Answer :a
Q31. The useful operational life of INSAT-IB (launched in 1983) is expected to end by
a. 1992-93
b. 1991-92
c. 1989-90
d. 1993-94
Answer : c
Q32. At present, the radio-frequency band mainly used by most satellites is ……….
a. EHF
b. UHF
c. VHF
d. SHF
Answer : d
Q33. Orbital disturbances of a geosynchronous satellite are caused by the
a. moon
b. sun
c. earth
d. all of the above
Answer : d
Q34. Which one of the following statement is correct?
a. Satellite spacing is not affected by the bandwidth of the transmitting earth station
b. Beamwidth is independent of antenna size and frequency band used
c. The width of a beam in space is inversely proportional to the width of the transmitting antenna
d. Use of high-frequency bands permits less number of satellites to share the orbit
Answer : c
Q35. In a stop-and-wait ARQ system, the transmitting terminal
a. waits for positive or negative acknowled-gement from the receiving terminal after sending a block
b. sends another block if positive acknowledge is received through ACK character
c. resends the previous block if negative acknowledgement is received through a NAK character
d. does not wait for acknowledgement after sending a block
Answer : d
Q36. A geostationary satellite is one which
a. hangs motionless in space about 36000 km about Earth
b. travels around the Earth in 24 hours
c. remains stationary above the Earth
d. appears stationary to everybody on Earth
Answer : d
Q37. The geostationary communication satellite APPLE is parked in the equatorial orbit at
a. 102° E longitude over Sumatra
b. 90° E longitude over Bangladesh
c. 74° E longitude over India
d. 67° E longitude over Pakistan
Answer : a
Q38. Power received from Sun per m2 surface area of a geosynchronous satellite in nearly…………. watt.
a. 100
b. 500
c. 2000
d. 1000
Answer : d
Q39. A certain sound has 10000 times more energy than another sound. The number of times it would sound stronger to a listener is
a. 40
b. 10000
c. 100
d. 10
Answer : a
Q40. The bandwidth of C- band satellite frequency band in U.C is ………
a. 500 GHz
b. 1000 GHz
c. 1000 MHz
d.
Answer : d
Q41. Repeaters inside communication satellites are known as ………
a.
b. Transponders
c. Transducers
d. TWT
Answer : b
Q42. What kind of battery panels are used in some advance satellites?
a. Germanium based panels
b. Silicon based panel
c.
d. Galium Arsenide solar panel array
Answer : d
Q43. What is the local oscillator (mixer) frequency of the satellite with an uplink frequency in GHz band?
a.
b. 4500 MHz
c. 2225 MHz
d. 2555 MHz
Answer : c
Q44. How many satellite orbital slots are requested by the Philippine Government from ITU ?
a. 2
b. 4
c. 6
d. 8
Answer : c
Q45. The switching from one element to the other element in a typical mobile satellite array.
a. Series
b. Radial
c. Matrix
d. Shunt
Answer : d
Q46. What circuit is responsible in activating and deactivating adjacent antenna elements in a mobile satellite array ?
a. Radial divider
b. Divider/combiner
c. Radial combiner
d. Radial multiplexer
Answer : a
Q47. INTELSAT stands for ………….
a. Intel Satellite
b. International Telephone Satellite
c. International Telecommunications Satellite
d. International Satellite
Answer : c
Q48. …………. is an artificial body that is projected from earth to orbit either earth (or) another body of solar systems.
a. Satellite
b. moon
c. sun
d. none of the above
Answer : a
Q49. ………… is defined as the use of orbiting satellites to receive, amplify and retransmit data to earth stations.
a. Optical communication
b. Digital communication
c. Analog communication
d. Satellite communication
Answer : d
Q50. ………… law states that the path followed by the satellite around the primary will be an ellipse.
a. Newton’s 1st law
b. kepler’s first law
c. kepler’s second law
d. kepler’s third law
Answer : b
Q51. Which law states that for equal time intervals, the satellite will sweep out equal areas in its orbital plane, focused at the barycenter.
a. Newton’s 1st law
b. kepler’s first law
c. kepler’s second law
d. kepler’s third law
Answer : c
Q52. Which law states that the square of the periodic time of orbit is perpendicular to the cube of the mean distance between the two bodies. A3 = 3/n2
a. Newton’s 1st law
b. kepler’s first law
c. kepler’s second law
d. kepler’s third law
Answer : d
Q53. What is meant by GPRS ?
a. General packet receiver service
b. General packet radio service
c. Global packet radio service
d. none of these
Answer : b
Q54. Television transmission is an example of which type of transmission?
a. Simplex
b. Half Duplex
c. Full Duplex
d. None of the above
Answer : a
Q55. What are the limitations of FDMA-satellite access?
a. If the traffic in the downlink is much heavier than that in the uplink, then FDMA is relatively inefficient.
b. Compared with TDMA, FDMA has less flexibility in reassigning channels.
c. Carrier frequency assignments are hardware controlled
d. all of the above
Answer : d
Q56. What is meant by EIRP?
a. Equivalent Isotropic Radiated Power
b. Energy Isotropic Radiated Power
c. Equivalent Isotropic Resonance Power
d. none of these
Answer : a
Q57. A satellite downlink at 12 GHz operates with a transmit power of 6 W and an antenna gain of 48.2 dB. Calculate the EIRP in dBW.
a. 45 dBW
b. 50 dBW
c. 75 dBW
d. 56 dBW
Answer : d
Q58. The range between a ground station and a satellite is 42000 km. Calculate the free space loss a frequency of 6 GHz.
a. 100 dB
b. 150 dB
c. 175dB
d. 200.4dB
Answer : d
Q59. The flux density required at the receiving antenna to produce saturation of TWTA is known as ……….
a. Electric flux density
b. Magnetic flux density
c. Saturation flux density
d. Photon flux density
Answer : c
Q60. ………….. is necessary to prevent the bursts from overlapping.
a. Preamble
b. Guard time
c. Frame efficiency
d. Decoding quenching
Answer : b
Q61. In some phase detection systems, the phase detector must be allowed for some time to recover from one burst before the next burst is receiving by it. This waiting time is known as …………
a. Preamble
b. Guard time
c. Frame efficiency
d. Decoding quenching
Answer : d
Q62. …………. is a measure of the fraction of frame time which is used for the transmission of traffic.
a. . Preamble
b. Guard time
c. Frame efficiency
d. Decoding quenching
Answer : c
Q63. What is meant by OMT ?
a. Orthogonal mode tube
b. Orthogonal modulation tube
c. Orthogonal mode transducer
d. none of these
Answer : c
Q64. Which of the following comes under methods of multiple access techniques?
a. FDMA & TDMA
b. SCPC & CDMA
c. CDMA & GSM
d. none of these
Answer : a
Q65. What is meant by SCPC?
a. Single channel per carrier
b. Single carrier per channel
c. Single code per channel
d. none of these
Answer : a
Q66. For satellite communication, standard Earth stations have antenna diameters in the range of ………….. metre.
a. 27.5 to 30
b. 10 to 15
c. 30 to 50
d. 5 to 10
Answer : a
Q67. The most effective anti jamming technique is ………..
a. frequency hopping
b. spread-spectrum modulation
c. key leverage
d. once-only key
Answer : b
Q68. The ending part of the popular teleserial Mahabharat will be beamed to the viewers
a. WESTAT
b. INSAT-IC
c. ARABSAT
d. INSAT-ID
Answer : c
Q69. A communication satellite is a repeater between …………… and …………..
a. a transmitting station and a receiving station
b. a transmitting station and many receiving station
c. many transmitting station and many receiving station
d. none
Answer : c
Q70. While keeping the down-link frequency constant, the diameter of a satellite antenna is reduced by half. To offer the same EIRP over the increased coverage area, the RF output power has to be increases by a factor of ………..
a. 2
b. 4
c. 8
d. 16
Answer : b
Q71. The Sun blots out the transmission of a geosynchronous satellite twice a year when satellite passes directly in front of it. This outage lasts for about
a. 10 minutes on 5 consecutive days
b. 5 minutes on 10 consecutive days
c. 30 minutes for 5 consecutive days
d. one hour for 5 consecutive days
Answer : a
Q72. In satellite communication, frequency modulation is used because satellite channel has
a. small bandwidth and negligible noise
b. large bandwidth and severe noise
c. maximum bandwidth and minimum noise
d. high modulation index
Answer : b
Q73. Which of the following factor does NOT contribute to the drift of a geostationary satellite from its stationary position in space?
a. Pressure of solar radiations
b. Gravitational changes due to Sun and Moon
c. Oblateness of the Earth
d. Weight of the satellite
Answer : d
Q74. In communication satellites, the up-link normally operates at a higher frequency than the down-link because it
a. gives a narrow beam shining into space
b. results in lesser signal attenuation
c. gives better beam-shaping
d. is easier to polarize a high frequency beam
Answer : a
Q75. For global communication, the number of satellites needed is
a. 1
b. 3
c. 10
d. 5
Answer : b
Q76. The noise temperature of sky is about __________ °K.
a. 100
b. 273
c. 0
d. 30
Answer : d
Q77. Assuming earth to be a sphere of radius 6400 km and height of a geosynchronous satellite above Earth as 36000 km, the velocity of a geosynchronous satellite is __________ km/hr.
a. 28000
b. 15000
c. 36000
d. 11100
Answer : d
Q78. In the context of error detection in satellite transmission, ARQ stands for ……………
a. Automatic Repeat Request
b. Automatic Relay Request
c. Accelerated Recovery Request
d. Automatic Radiation Quenching
Answer : a
Q79. To cover all inhabited regions of the Earth, the number of geosynchronous communication satellites required
a. 5
b. 3
c. 10
d. 2
Answer : b
Q80. Depending on the technique used, digitized television requires a bit rate between __________ millions.
a. 40 and 92.5
b. 25 and 60
c. 30 and 82.5
d. 2
Answer : a
Q81. In selecting a satellite system, the First determining factor is its
a. EIRP
b. antenna size
c. coverage a sea
d. antenna gain
Answer : c
Q82. Phase modulation is commonly-used for data transmission mainly because
a. phase can be varied from + 180° to 180°
b. it is resistant to the effects of noise
c. demodulation is very easy
d. it gives highest data rates that can be transmitted over a given channel
Answer : b
Q83. India’s Polar Satellite Launch vehicle (PSLV) to be ready in 1991 is designed to launch 1000 kg spacecraft into __________ orbit.
a. geostationary
b. equatorial
c. polar
d. sun-synchronous polar
Answer : d
Q84. Most of the communication satellites are stationed to the West of their service areas in order to reduce their ………..
a. eclipse period
b. loss of power
c. battery power provision
d. mass of station-keeping fuel
Answer : c
Q85. The degradation of satellite solar cells with time is mainly due to
a. their bombardment by electrons
b. collection of meteoric dust
c. increase in resistivity of silicon
d. gradual leakage of charge carriers from the semiconductor material
Answer : a
Q86. The echo heard by a telephone user on a satellite channel can be removed by using
a. a vocoder
b. a multiplexer
c. echo suppressor
d. digital techniques
Answer : c
Q87. The 1150 kg geosynchronous satellite INSAT-IA parked 36000 km above India had greatly improved India’s
a. intelligence gathering capacity
b. domestic communications
c. meteorological capability
d. both (b) and (c)
Answer : d
Q88. Presently, the worlds’s largest and most advanced multi-purpose communication satellite is ……………
a. INSAT-2
b. Intelsat-V
c. INSAT-ID
d. Olympus-I
Answer : d
Q89. A satellite link uses different frequencies for receiving and transmitting in order to ……..
a. avoid interference from terrestrial microwave links
b. avoid interference between its powerful transmitted signal and weak in coming signal
c. minimise free-space losses
d. maximise antenna gain
Answer : b
Q90. Regarding TASI which one of the following statements is wrong?
a. It snatches the channel in his speech and may allocate it to another speaker needing it.
b. The same speaker is reassigned a channel almost instantly when he speaks again even when the circuit is heavily loaded.
c. It increases the overall utilization of the transmission channel.
d. Intercontinental callers sometimes confuse the effects of TASI with the effects of satellite delay
Answer : b
Q91. Master control facility (MCF) for INSAT-2 series satellites is located at …………..
a. Madras
b. New Delhi
c. Leh
d. Hassan
Answer : d
Q92. The communication satellite INSAT-IB had to take up the job of INSAT-IA because the latter collapsed within …………… months of its launch.
a. 12
b. 20
c. 5
d. 36
Answer : c
Q93. The distance of a synchronous satellite from Earth’s surface is ………….. km.
a. 300
b. 10000
c.35900
d. 5
Answer : c
Q94. The traffic-handling capacity of an Earth station on the uplink depends on …………
a. its EIRP
b. satellite antenna gain
c. noise associated with the satellite
d. all of the above
Answer : d
Q95. System satellites orbit the Earth once in …………. hrs.
a. 24
b. 12
c. 1
d. 6
Answer : a
Q96. The lowest frequency used in satellite communications is ……….. GHz.
a. 0.8
b. 3
c. 18
d. 30
Answer : a
Q97. Geosynchronous satellites are always launched in the equatorial plane because it is the only plane which provides
a. 24-hour orbit
b. stationary satellite
c. global communication
d. zero-gravity environs
Answer : c
Q98. A few minutes disturbance in space communications occurs twice a year during Sunblinding when __________ are in line.
a. Sun and satellite
b. Sun and Earth station
c. Satellite and Earth station
d. Sun, satellite and Earth station
Answer : d
Q99. After the death of INSAT-IB, the mainstay of the entire Indian satellite network for some time to come would be
a. INSTELSAT-V
b. INSAT-ID
c. INSAT-2
d. ARABSAT
Answer : d
Q100. For satellite transmission, analog signals may be converted into digital form with the help of ……………..
a. modem
b. transponder
c. codec
d. compandor
Answer : c
Q101. The maximum signal propagation time of a geosynchronous satellite transmission is about ……….. millisecond
a. 540
b. 270
c. 135
d. 1080
Answer : b
Q102. The life time of a geosynchronous communication ……..
a. 5
b. 10
c. 20
d. 50
Answer : b
Q103. A typical error rate on satellite circuits is one bit error in
a. 107
b. 103
c. 102
d. 1010
Answer : a
Q104. In satellite communication, highly directional antennas are used to
a. direct the spot beam to a particular region of space on Earth
b. strengthen the beam to overcome the cosmic noise
c. make corrections in change of polarisation of the beam
d. select a particular channel in transmission and reception
Answer : a
Q105. The average noise temperature of Earth, as viewed from space, is ………. °K
a. 254
b. 303
c. 100
d. 500
Answer : a
Q106. Low-orbit satellites are not used for communications because they
a. produce sonic booms
b. do not provide 24 hour/ day contact to the users on Earth
c. heat up and melt
d. none
Answer : c
