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

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

单项选择题When using the ARPA in heavy rain，which action should you take? （）

A.Increase the radar gain to pick up weak echoes through the rain
B.Increase the STC setting to reduce close-in spurious signals
C.Navigate as though the effective range of the radar has been reduced
D.Increase the range of the inner and outer guard rings

单项选择题When using an ARPA，what should you consider in order to evaluate the information displayed?（）

A.The target vessel's generated course and speed are based solely on radar inputs
B.Navigational constraints may require a target vessel to change course
C.The trial maneuver feature will automatically determine a course that will clear all targets
D.You cannot determine if a small target has been lost due to sea return