單項(xiàng)選擇題Most modern Loran-C receivers，when not tracking properly，have a（n）（）.

A.Bell alarm to warn the user
B.Lighted alarm signal to warn the user
C.Alternate signal keying system
D.View finder for each station


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1.單項(xiàng)選擇題Loran-C uses the multiple pulse system because（）.

A.Less signal energy is necessary for receiver operation
B.More signal energy is available at the receiver
C.It significantly increases the peak power
D.It increases the signal capacity

2.單項(xiàng)選擇題Loran-C is which type of system（）.

A.Reflected electron
B.Electrical radiation
C.Quarterpoint electrical navigation
D.Hyperbolic radio navigation

3.單項(xiàng)選擇題In using Loran-C，skywave reception gives greater range but is（）.

A.only accurate during daylight hours
B.much less accurate
C.only accurate at twilight
D.more accurate than using ground waves

5.單項(xiàng)選擇題Automatic identification systems（AIS）are required to（）.

A.provide safety-related information automatically to shore stations，other vessels and aircraft
B.receive safety-related information automatically from similarly equipped vessels
C.exchange safety-related information with shore-based facilities
D.All of the above