A.radio signals reflect from a solid surface
B.sound waves travel at a constant speed through water
C.radar signals travel at a constant speed through water
D.pressure increases with depth
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A.Water temperature
B.Climatology data
C.Speed of advance
D.Depth contours
A.Soundings
B.Waypoints
C.Meteorological data
D.Radar targets
A.Radar targets
B.ARPA vectors
C.Hydrographic data
D.All of the above
A.beam
B.radar
C.light beacon
D.reflector
A.Straight line
B.Arc
C.Parabola
D.Hyperbola
最新試題
Error may be introduced into a magnetic compass by（）.
A Doppler log in the volume reverberation mode indicates（）.
An indirect radar echo is caused by a reflection of the main lobe of the radar beam off the observer’s vessel. Which of the following is NOT a characteristic of indirect echoes?（）.
A deadhead is a(n)（）.
An electronic depth finder operates on the principle that（）.
The transmission time duration of a single pulse of radio-frequency energy is a function of the（）.
A Doppler speed log indicates speed over ground（）.
The number of pulses of energy transmitted per second is call the（）.
Deviation is the angle between the（）.
Compass deviation is caused by（）.