11.2 雷达及ARPA的使用（38题）
1. ______ is not a job of the radar antenna．
A．To receive the high-frequency pulses from the transmitter
B．To focus the pulses into a beam，and send them into space
C．To pick up reflected pulses coming from objects that have been struck by the beam
D．To reflect microwaves
2. ______ is not used in modern radar．
A．EBL
B．VRM
C．CRT
D．Grease pencil
3. ______ typically extends from close as 0.1 nautical miles out to 32 NM．
A．EBL
B．VRM
C．CRT
D．target tracking range
4. Although manual plotting for CPA works well，the workload can become overwhelming when confronted with ______．
A．one target
B．two targets
C．three targets
D．a large number of targets
5. I ______ shorebased radar assistance．
A．Ask
B．Look for
C．Require
D．In need of
6. In fog you observe your radar and determine that risk of collision exists with a vessel which is 2 miles off your port bow．You should ______．
A．stop your engines
B．sound the danger signal at two-minute intervals
C．hold course and speed until the other vessel is sighted
D．take avoiding action as soon as possible
7. My radar is not working．I require shore based radar assistance．Is shore based radar assistance ________?
A．used
B．available
C．in use
D．can be used
8. PPI is ______．
A．a plan-position indicator system
B．pulse-plan integration
C．pulse-pulse input
D．power-plan input
9. Radar makes it possible and much safer for us to sail ______．
A．In dense fog
B．In boisterous weather
C．In the open sea
D．In rivers
10. Radar reflectors are required for ______．
A．all fishing vessels over 39 feet in length
B．sail-propelled fishing vessels
C．all fishing vessels of less than 200 GT
D．wooden hull fishing vessels with a poor radar echo
11. SWEEP INT on radar panel is the abbreviation of ______．
A．sweep introduction
B．sweep interest
C．sweep intention
D．sweep intensity
12. The ______ has a built-in world map; most areas are displayed on a scale of 4000 nm from the top to the bottom of the screen，and can be zoomed in to 150 nm．
A．chartplotter
B．C-MAP NT
C．C-Cards
D．PPI
13. The 10-cm radar as compared to a 3-cm radar of similar specifications will ______．
A．Be more suitable for river and harbor navigation
B．Provide better range performance on low lying targets during good weather and calm seas
C．Have a wider horizontal beam width
D．Have more sea return during rough sea conditions
14. The articulated light is superior to other types of buoys because ______．
A．The radar reflectors reflect better signals
B．Fog horn signals travel farther to sea
C．It is equipped with strobe lights
D．It has a reduced watch circle
15. The closest point of approach（CPA）of a contact on a relative motion radar may be determined ______．
A．Immediately when the contact is noted on radar
B．Only if the radar scope is watched constantly
C．After the contact has been marked at least twice
D．By an occasional glance at the radar
16. The correct method of switching off a marine radar is to turn power switch to ______ position first，then to ______ position．
A．Off/standby
B．Standby/off
C．Standby/close
D．Close/standby
17. The development of ______ led to the fully automatic ARPA systems installed on commercial ships．
A．SeaTalk
B．powerful microprocessors and mega memory capacity
C．chartplotter
D．small-scale chart
18. The radar control that reduces weak echoes out to a limited distance from the ship is the ______．
A．sensitivity time control（sea-clutter control）
B．receiver gain control
C．brilliance control
D．fast time constant（differentiator）
19. The radar control used to reduce sea return at close ranges is the ______．
A．Gain control
B．Sensitivity time control
C．Fast time constant
D．Pulse length control
20. The radio waves used for radar are very short，only ______ long．
A．A few centimeters
B．A few fathoms
C．A few meters
D．A few feet
21. The shoreline along Rocky Point should give a good radar return because ______．
A．The shore is bluff and rocky
B．Of offshore exposed rocks
C．Submerged reefs cause prominent breakers
D．The lookout tower is marked with radar reflectors
22. To determine if risk of collision exists，a vessel which is fitted with radar must use
______．
A．Radar scanning
B．Radar plotting
C．Compass bearings
D．All of the above
23. What is TRUE when operating in fog and other vessels are detected by radar ________．
A．You should make an ample change to port for a vessel crossing on the starboard bow
B．You should maneuver in ample time if a close-quarters situation is developing
C．You should determine the course and speed of all radar contacts at six minute intervals
D．Long-range scanning will provide early warning of ALL other vessels within the radar's range
24. What provides little or no indication that a vessel is dragging anchor ________．
A．Increasing radar range to a fixed object ahead
B．Drift lead with the line leading perpendicular to the centerline
C．Vibrations felt by placing a hand on the cable
D．Changing bearings to distant fixed objects abeam
25. What will cause the ARPA to emit a visual alarm，audible alarm，or both ________．
A．An acquired target entering into a guard zone
B．A tracked target lost for one radar scan
C．A tracked target entering your preset CPA-TCPA limits
D．A target being initially detected within a guard zone
26. When the relative motion display is selected all tracked objects will display ______ vectors．
A．motion
B．stationary
C．dynamical
D．flashing
27. 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
28. 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
29. Which condition indicates that your radar needs maintenance ________．
A．Serrated range rings
B．Indirect echoes
C．Multiple echoes
D．Blind sector
30. 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
31. Which statement concerning the operation of radar in fog is TRUE ________．
A．Radar ranges are less accurate in fog
B．Navigation buoys will always show up on radar
C．A sandy beach will show up clearer on radar than a rocky cliff
D．Small wooden boats may not show up on radar
32. You are scanning the radar screen for a buoy fitted with racon．How should this signal appear on the PPI display ________．
A．Starting with a dash and extending radially outward from the target
B．As a broken line from center of PPI to the target
C．Starting with a dot and extending radially inward from the target
D．Starting with a dash and extending to the right of the target
33. You have another ship overtaking you close aboard to starboard. You have 3 radar targets bearing 090° relative at ranges of 0.5 mile，1 mile，and 1.5 miles．In this case，the unwanted echoes are called ______．
A．Multiple echoes
B．Spoking
C．Indirect echoes
D．Side-lobe echoes
34. Your ARPA has automatic speed inputs from the log．Due to currents，the log is indicating a faster speed than the speed over the ground．What should you expect under these circumstances ________．
A．The generated CPA will be less than the actual CPA
B．The generated TCPA will be later than the actual TCPA
C．The range of initial target acquisition will be less than normal
D．The targets true course vector will be in error
35. Your ARPA has been tracking a target and has generated the targets course and speed．The radar did not receive a target echo on its last two scans due to the weather．What should you expect under these circumstances ________．
A．The ARPA will generate data as if the target was still being tracked by radar
B．The ARPA will give an audible and/or visual lost target alarm
C．The ARPA will generate data based on sea return echoes from the vicinity where the target was lost
D．The ARPA has lost all memory of the target and must recompute the target data
36. Your ARPA has two guard zones．What is the purpose of the inner guard zone ________．
A．Alert the watch officer that a vessel is approaching the preset CPA limit
B．Warn of small targets that are initially detected closer than the outer guard zone
C．Guard against target loss during critical maneuvering situations
D．Sound an alarm for targets first detected within the zone
37. Your radar displays your ship off center．As you proceed on your course, your ship's marker moves on the PPI scope while echoes from land masses remain stationary．What is this display called ________．
A．Off center
B．True motion
C．Stabilized
D．Head up
38. Your radar is set on a true motion display．Which of the following will NOT appear to move across the PPI scope ________．
A．Echoes from a buoy
B．Own ship's marker
C．Echo from a ship on the same course at the same speed
D．Echo from a ship on a reciprocal course at the same speed
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