WorksheetsQuiz on Section 1
Total questions: 40
Worksheet time: 22mins
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 ……………….. meter.
100
4
1
10
A transponder is a satellite equipment which………………………………………………………………………
receives a signal from Earth station and amplifies
changes the frequency of the received signal
re-transmits the received signal
all of the above
A geosynchronous satellite……………………………………………
has the same period a that of the Earth
has a circular orbit
rotates in the equatorial plane
all of the above
To make antenna more directional, either its size must be increased or
the number of its feed horns must be increased
the frequency of its transmission must be increased
its effective isotropic radiated power (EIRP) must be increased
its footprint must be increased
The number of days when Earth's shadow falls on a geosynchronous satellite is………………………
88
277
5
10
At present, the radio-frequency band mainly used by most satellites is……
EHF
VHF
UHF
SHF
The quality of a space-link is measured in terms of the __________ ratio.
C/N
S/N
G/T
EIRP
Orbital disturbances of a geosynchronous satellite are caused by the………………
Moon
Sun
Earth
All of above
Which one of the following statement is correct?
Satellite spacing is not affected by the bandwidth of the transmitting earth station
Beam width is independent of antenna size and frequency band used
The width of a beam in space is inversely proportional to the width of the transmitting antenna
Use of high-frequency bands permits less number of satellites to share the orbit
A helical antenna is used for satellite tracking because of
circular polarization
maneuverability
beam width
gain
The expression for satellite link frequencies such as 4/6 GHz denotes that
4 GHz is the up-link and 6 GHz is the down-link frequency
4 GHz is the down-link and 6 GHz is the up-link frequency
the system operates at a mean frequency of 5 GHz
one frequency is used as a back up for the other
To cover all inhabited regions of the Earth, the number of geosynchronous communication satellites required
5
3
10
2
The different access methods which permit many satellite users to operate in parallel through a single transponder without interfering with each other as
FDMA
TDMA
CDMA
All of the above
In envelope detection of an AM waveform
One side band and full amplitude carrier are needed
Both side bands and full amplitude carrier are needed
Only two side bands are needed
Upper side band and part of carrier are needed
India's first three-axis stabilized geostationary communication satellite is
Rohini
Aryabhatta
Apple
Bhaskara
In synchronous detection of an AM signal
Carrier is completely suppressed
Both side bands are suppressed
Only one side band and part of carrier is suppressed
One side band and full carrier is suppressed
A telephone user while talking to a person via a satellite has to wait for reply for about __________ millisecond.
100
270
470
540
Space communication links are being increasingly moved into Ka-band (20-30 GHz) because it
offers a much wider available bandwidth
does not suffer from atmospheric attenuation
permits the use of smaller antenna
does not suffer from rain attenuation
In selecting a satellite system, the First determining factor is its
EIRP
antenna size
coverage area
antenna gain
Phase modulation is commonly-used for data transmission mainly because
phase can be varied from + 180° to 180°
it is resistant to the effects of noise
demodulation is very easy
it gives highest data rates that can be transmitted over a given channel
Repeaters inside communications satellites are known as……………………………
Transceivers
Transponders
Transducers
TWT
Collects very weak signals from a broadcast satellite
Helical antenna
Satellite dish
LNA
TWT
-------Is a loss of power of a satellite downlink signal due to earth’s atmosphere.
Atmospheric loss
Path loss
Radiation loss
Radio frequency interference
………………………..Is the geographical representation of a satellite antenna radiation pattern
Footprint
Spot beam
Earth
Region
What is the frequency range of C-band?
8.5 to 12.5 GHz
3.7 to 6.425 GHz
12.95 to 14.95 GHz
27.5 to 31 GHz
The frequency of Ku band for satellite communications.
6/4 GHz
14/11 GHz
12/14 GHz
4/8 GHz
Earth station uses what type of antenna
Despun antenna
Helical antenna
Toroidal antenna
Cassegrain antenna
The satellite communications channels in a transponder are defined by the ……………
LNA
band pass filter
mixer
input signals
Satellite engine uses
Jet propulsion
Ion propulsion system
Liquid fuel
Solar jet
What kind of battery used by older satellites?
Lithium
Leclanche
Hydrogen
Magnesium
India's Polar Satellite Launch vehicle (PSLV) to be ready in 1991 is designed to launch 1000 kg spacecraft into __________ orbit.
geostationary
equatorial
polar
sun-synchronous polar
The most common device used as an LNA is
Zener diode
Tunnel diode
IMPATT
Shockley diode
What kind of battery panels are used in some advance satellites
Germanium based panels
Silicon based panel
Galium Arsenide solar panel array
Galium Phosphate solar panel array
A method of multiple accessing where a given RF channel bandwidth is divided inot smaller frequency band.
CDMA
TDMA
FDMA
Non of above
------is a satellite that rotates around the earth in a low-altitude elliptical or circular pattern.
Geosynchronous satellite
Non-synchronous satellite
Prograde satellite
Retrograde satellite
Choose Most Relevant Answer:
A geostationary satellite is one which -------
hangs motionless in space about 36000 km above Earth
travels around the Earth in 24 hours
remains stationary above the Earth
appears stationary to everybody on Earth
A certain sound has 10000 times more energy than another sound. The number of times it would sound stronger to a listener is------- dB
40
10000
100
10
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------
2
4
8
16
A communication satellite is a repeater between----
a transmitting station and a receiving station
a transmitting station and many receiving station
many transmitting station and many receiving station
none of above
For satellite communication, standard Earth stations have antenna diameters in the range of __________ metres.
27.5 to 30
10 to 15
30 to 50
5 to 10
