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3-28. When compared to hf communications,
which of the following advantages are
unique to satellite communications links?
1. They are more reliable and flexible
2. They are unaffected by propagation
variations affecting hf
3. They do not require repeater stations
or troposcatter links
4. Each of the above
3-29. Which of the following factors limits the
reliability of active satellite
communications system?
1. The reflection or refraction of signals
2. The reliability of the equipment used
3. The skill of the operating and
maintenance personnel
4. Both 2 and 3 above
3-30. An increase of invulnerability to
jamming of satellite communications
systems is seen through the use of which
of the following features?
1. Narrow bandwidths
2. Low transmitter output power
3. Antijamming modulation techniques
4. Omnidirectional earth terminal
Antennas
3-31. Which of the following statements best
describes the advantage of satellite
communications in terms of flexibility?
1. The antenna group of any earth
terminal can be mounted on the
weather deck of a ship
2. Certain earth terminals are housed in
vans and can be transported to remote
areas
3. Military satellite communications are
capable of handling hundreds of voice
channels
4. A high degree of protection from
jamming is afforded by the highly
Directional antennas at earth
terminals
3-32. A satellite communications system is
limited by which of the following
characteristics?
1. The attitude of the satellite repeater
2. The technical design of the satellite
3. The immobility of the satellite
4. The mobility of the satellite
3-33. Active communications satellite systems
have two major limitations. What are
they?
1. Complex preamplifiers and high gain
antennas
2. Up-link transmitter power and earth
terminal antenna size
3. Down-link transmitter power and
uplink receiver sensitivity
4. Down-link receiver sensitivity and
external atmospheric noise
3-34. The rf power output of a satellite
communications system is severely
limited due to which of the following
factors?
1. A lack of adequate jamming
capabilities
2. An inefficient solar-cell package
aboard the satellite
3. An unstable satellite orientation with
respect to the horizon
4. A requirement for large antenna-farm
earth-terminal systems
3-35. The availability of a satellite to act as a
relay station between two earth terminals
depends upon which of the following
considerations?
1. The mobility of the satellite
2. The location of the earth terminals
3. The operating frequencies of the
satellite
4. The electronic design of the earth
terminals
