单项选择题

Which general statement concerning radar is FALSE?（）.

A.Raising the antenna height increases the radar range
B.The ability of radar to detect objects is unaffected by weather conditions
C.Radar bearings are less accurate than radar ranges
D.Radar should be checked regularly during clear weather to ensure that it is operating properly

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单项选择题Which condition indicates that your radar needs maintenance?（）

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

单项选择题Which ARPA data should you use in order to determine if a close quarters situation will develop with a target vessel? （）

A.Set and drift of the current
B.Relative track information
C.Predicted time of CPA
D.Initial range of acquisition

单项选择题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 navigation

单项选择题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

单项选择题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