默认题库 - 雷达及ARPA的使用

单选题

When using the radar for navigating（）.

A. the best fix is obtained by using a tangent bearing and a range
B. and using two radar ranges for a fix，the objects of the ranges should be close to reciprocal bearings
C. and using ranges，the most rapidly changing range should be measured last
D. and crossing a radar range of one object with the visual bearing of a second object，the two objects should be 80°to 110°apart

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单选题

When you turn on the fast time constant (differentiator) control of a radar it will（）.

A. enhance weak target echoes and brighten them on the PPI
B. reduce clutter over the entire PPI by shortening the echoes
C. only suppress weak targets to a limited distance from the ship (sea clutter)
D. reduce the beam width to provide a map-like presentation for navigatio

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单选题

Which condition indicates that your radar needs maintenance?（）

A. Serrated range rings
B. Indirect echoes
C. Multiple echoes
D. Blind sector

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单选题

Which procedure(s) shall be used to determine risk of collision? （）

A. Watching the compass bearing of an approaching vessel
B. Systematic observation of objects detected by radar
C. Long-range radar scanning
D. All of the above

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单选题

Which statement about an estimated position is TRUE?（）

A. It is more reliable than a fix based on radar bearings
B. It may be based on a single LOP or questionable data
C. When a 3-LOP fix plots in a triangle，the center of the triangle is the estimated position
D. It is usually based on sounding

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单选题

When will the float-free emergency position indicating radiobeacon be activated after abandoning ship? （）

A. Immediately after floating free
B. After about one hour when the salt water activates the battery
C. Only when keyed by the radar of another vessel
D. Only when daylight activates the photovoltaic cell

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单选题