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1
An estimated point in which of the distance between two objects of which at least one is in motion will reach a minimum value?
closest point of approach
2
Regarding performance standard for navigational radar, what are the requirements for a scanner?
plus or minus 1 degree
3
Which statement is true concerning a vessel equipped with operational radar?
she must use this equipment to obtain early warning of risk of collision
4
Answer only
the test function on the SART
5
Which arpa data should you use in order to determine if a close quarter situation with another vessel is developing or not?
relative track of information
6
Two ships approach each other on reciprocal course, one with a speed of 22 knots, the other with 15 knots, what is the relative speed?
37 knots
7
What is one good practice of a navigator fixing a vessel position by means of radar?
can use radar information from one object to fix the position
8
Indicate three important target data which can be received from radar tracking of the vessel?
course, speed and risk of collision
9
You radar displayed your ship off center. As you proceed on your course, your ships marker moves on the PPI scope while echoes from land masses remain stationary. What do you call this kind of display?
true motion
10
With regards to arpa, what does the lost target warning tell?
target can no longer be plotted
11
How can a rescue personnel detect that a SART is transmitting in the immediate vicinity?
The SART's blips on the PPI will become arcs and eventually become concentric circle
12
What is the best land target to be used for radar ranging?
a cliff face
13
What must be the minimum activated AIS target capacity of an arpa?
40 targets
14
When can you determine the closest point of approach (CPA) of a contact on a relative motion radar?
after the contact has been marked at least twice
15
If a layer of cold moist air over rides a shallow layer of warm dry air which of the following may occur?
sub-refraction
16
What is the common radar frequency ranges of bands used in coastal radar system?
3-30 MHz
17
Trial maneuver in arpa fitted on vessels of over what tonnage?
10,000 gt
18
What caused the presentation of coral atolls or a chain of islands as long line rather than as an individual targets?
the effects of the beam width
19
What is the process of calculating target motion based on past position by arpa?
smoothing
20
How is the line position derived by radar range be represented on the CRT?
As an arc
21
What is the operational check you should carry out when a radar set is installed?
check the accuracy of the heading marker
22
In calm and clutter free condition, what is the minimum detection range of X-Band radar if the target is a 5 m tall SOLAS ship (less than 5,000 gross tonnage)?
8 nm
23
When is the transmitted signal of the SART will be most conspicuous on the radar screen?
when the receiver is not fined tuned
24
Vessels required to have an automatic radar plotting aid must have a device to indicate the.
speed of the vessel over the ground or through the water
25
What is the main concern when using the radar for coastal position fixing?
to obtain the most accurate fix.
26
A listing of radar aid to navigation
the radar system should be capable of displaying two targets on the same bearing, separated by 40 m in range, as two distinct objects
27
Answer only
the Master may, at his/her discretion, turn off the AIS if he/she believes that it may compromise the safety or security of the vessel.
28
You have another ship overtaking you close a board to starboard. You have three radar targets bearing 090°, relative ranges 0.5 nm, 1 nm and 1.5 mm. In this case, what do you call the unwanted echoes?
multiple echoes
29
What is true of the history display of a target past position on an arpa?
in the true presentation, it provides a quick visual check to determine if a vessel has changed course
30
Answer only
transform a local datum to WGS-84 datum
31
Which of the following radar presentation feature can be used to advantage for position fixing?
an off-centered display
32
Which of the following is NOT recommendable to obtain vessels position as radar target?
floating aids
33
What is the purpose of function of the "Trial Mode" use in most alpha equipment?
it is used to allow results of proposed maneuvers to be assessed
34
Answer only
successive bearings of a pipe in radar does not necessarily give the course and speed of that pip
35
Navigation at coastal waters, radar is generally used to supplement
visual fixing
36
What is the maximum number of minutes you should wait until utilizing ARPA data for collision avoidance decision making?
3 minutes
37
Which of the following is included in the international regulations for prevention of collision at sea?
instructions on action to take while plotting a ship by radar
38
What is one good practice of a navigator fixing a vessel position by means of radar?
can use radar information from one object to fix the position
39
When radar display is set so that your vessel appears at the center of the screen in the heading is set to always point zero degrees to the observerings can be defined by which of the following?
relative
40
What should be the range accuracy of typical radar?
within 1.5% of the range scale in use
41
Which mode of the arpa that when it is used properly, it will produce greater accuracy?
ground stabilized
42
The radar has display has sectors of solid video (spoking). What would be the first thing to check?
for interference from nearby ships
43
The transmission time duration of a single pulse of radio frequency energy is a function of the
pulse length
44
In radar principle, what measures may be taken to minimize dangers from blind spot?
frequent change of PRF from low to high and vice versa and observing results on the screen
45
If your vessel, while proceeding north at 15 knots, observed by radar a stationary target, what would be the approximate direction and rate at which the pip would move on your PPI scope?
south at 15 knots
46
After 3 minutes of tracking, ARPA should provides CPA to what accuracy?
within 0.3 miles
47
Which of the following has the most effect on the definition of small target on the radar display?
horizontal beam width
48
How would you categorize the characteristic of SART transmitted signal?
it starts with a sweep of 0.4 usec across the entire 3 cm radar band, followed by a returning sweep of 7.6 usec. back to the beginning for a total of 12 sweeps.
49
What is the name of the movable guideline used to measure direction on a radar?
cursor
50
Your arpa has been tracking a target and has generated the targets data. The radar did not receive a target echo on its last two scans due to the weather. What should you expect under this circumstances.
the arpa will generate alarm as if the target is still being tracked by radar
51
What will cause the ARPA to emit a visual alarm, audible alarm, or both?
a target being initially selected with a guard zone
52
What should you do to establish an additional radar target data other than closest point of approach on a relative plot?
draw a relative velocity triangle
53
What should you do in order to ensure that a RACON signal displayed on the radar?
turn off the interference controls on the radar
54
What are the advantages of manually acquiring arpa targets?
operator can control the number of the acquired targets
55
From which of the following does an arpa builds up the track history of a target?
series of its range and bearings
56
What is the radar display in which north is always at the top of the screen?
stabilized display
57
An indirect radar echo is caused by a reflection of the main lobe of the radar beam of the observer's vessel. Which of the following is a characteristic of indirect echoes?
The bearing is almost constant, even when the true bearing of the contact changes appreciably.
58
Under rule 5 of the colregs, when should the radar be used for keeping a proper lookout?
whenever it may help
59
Answer only
the speed of a target relative to own ships position
60
What ratio would be used by a typical arpa before writing a target into the final switch register?
5 returns to 10 pulses
61
In what time frame and arpa should present a steady state tracking the motion of a target with the following accuracy values (95% probability values)
within 3 minutes
62
What is the purpose of digitizing the radar echoes in arpa?
the arpa tracking only works with digital signals
63
What is the characteristics on which bearing resolution depends?
beam width and range
64
In a radar system constant, what is the typical pulse repetition frequency?
500 to 3,000 pulses per second
65
What is the radar control that shortens all echoes on the display and reduces clutter caused by rain and snow?
fast time constant (differentiator)
66
Answer only
west at 20 knots
67
With regard to arpa, what does the "lost target" warning denotes?
targets can no longer be plotted
68
The following are navigational system that work with arpa except?
echo sounder
69
The description "Racon" beside an illustration on a chart would mean a
radar transponder beacon
70
Which statement is true concerning risk of collision?
proper use shall be made of radar equipment to determine risk of collision is developing
71
What facts show that an operator should carry out an operational check when a radar set is installed?
to determine the limits of shadow sectors
72
Answer only
warn of a small targets that are initially detected closer than the outer guard zone
73
What is the average range of ships surface search radar unit?
40 n miles
74
When you are approaching a RACON fated with a LIGHT, how would the racon be identified on the radar?
a coded signal triggered on the same bearing at a greater range than the light
75
Which of the following control is provided to check over all efficiency of the radar?
performance monitor
76
What are two most important pieces of input information required to operate the arpa accurately?
speed and heading
77
What is the performance standard set by the international maritime organization for the radar bearing discrimination?
The radar system should be capable of displaying two point targets at the same range, separated by 2.5 degrees in bearing, as two distinct objects
78
When two tracked targets are very close to each other, what do you call the process where the radar data of one target ships over to the other target?
target swap
79
What would be the effect of attenuation in radar performance?
reduce detection ranges
80
When using a radar in an unstabilized mode, how can you determine fixes easily?
from ranges
81
How long will it takes for the radar to be fully operational from the standby position?
within 5 seconds
82
When using the ARPA in heavy rain, which action should you take?
navigate as though the effective range of the radar has been reduced
83
Which of the following is an IMO performance standard of arpa requirement for ships over 10,000 gt?
Manually acquire at least 40 targets
84
What is the IMO requirement for arpa detection?
performance not inferior to the radar display
85
What is true when operating in fog and other vessels are detected by radar?
you should maneuver in ample time if a closed quarter situation is developing
86
In fog, you observe your radar and determine that risk of collision exist with a vessel with is 2 miles of your port bow. Which action should you take?
take avoiding action as soon as possible
87
You are scanning the radar screen for a buoy fitted with racon. How should the signal appear on the PPI display?
starting with a dash and extending radially outward from the target
88
When on automatic tracking operation, how would the two targets presented by arpa may swap information?
when passing close together
89
The type of radar enhance to maximum visibility in marginal weather condition?
S-Band
90
How are sea clutter echoes appear on the radar screen?
a mass of small echoes around the screen center
91
Your vessel is making 10 knots. After several observation of a target, it remain in the same position relative to yours, what could be the possible analysis of the situation?
the target is on the same course and speed as your vessel
92
What is the meaning of XXT at the bottom of the display in ARPA?
trial mode
93
The raider display has sectors of solid video (spoking) . What would be the first thing to check?
for interference from nearby ships
94
During navigation while arpa running, you have the option to have two guide zones at the same time. What is the purpose of the inner guard zone?
to give warning on small targets that are not initially detected by the outer guard zone
95
If the gyro fails, in which display would the arpa default into?
Head-up
96
You are using a radar which your own ships is shown at the center, and the heading flash always points to 0 degree. If bearings are measured in relation to the flash, what type of bearings are produced?
relative bearing
97
When using the arpa in heavy rain, which action should you take?
increase the FTC setting to reduce close in spurious signal
98
Which of the following performance standards requirements of IMO for ARPA for ships over 10,000 grt?
Manually acquire at least 40 targets
99
What is the range discrimination of a radar set of pulse length 60 meters?
30 meters
100
What does the description "RACON" beside an illustration on a chart wood mean?
radar conspicuous beacon