Welcome to the website where you can pass online the Seafarer Evaluation Training System (SETS) test on «Radar». Practice like this will help you as a marine specialist improve your knowledge with the help of online studying and appraisal practice. SETS based on practical information and marine specialists experience.
SETS tests developed for evaluating seaman basic knowledge by company “Naval Education Services” is an evaluating online-tool, used for revealing any professional preparation needed in specific fields of knowledge, defined by STCW Section A-V/1-2.
SETS tests have proven themselves as good tools for the selection and recruitment process, as well as advancing the level of knowledge of the current officers and crew.
Current test contains SETS questions in area «Radar». Those questions can be used for competence verification specialist capable of preventing accidental situations related with transporting safety, or also for self-examination.
«Radar» subject includes theoretical and practical information about advanced training for work on any type of vessel. This test assesses knowledge and skills required for safe navigation using radar systems. It includes questions on radar principles, signal propagation and interpretation of radar images. Participants must demonstrate understanding of radar settings such as gain, sea clutter and range. The test evaluates the ability to identify and track targets using ARPA (Automatic Radar Plotting Aids). Practical tasks may involve collision avoidance scenarios under restricted visibility. Sailors are tested on the International Regulations for Preventing Collisions at Sea (COLREGss) as applied with radar. The test may include simulations of radar plotting and relative motion analysis. Successful completion confirms a seafarer’s readiness to operate radar on any type of vessel during navigation.
On this site SETS on the subject «Radar» contains 252 questions you need to answer with no possibility to go back to previous question. Therefore, we recommend carefully reading each question and making decision with no hurry. In case you have some difficulty answering, you have also possibility to request a hint.
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Use the search below to find question.
Amount of questions: 252.
Right answers marked with this sign .
Attenuation is likely to cause ....
reduced detection ranges.
shadow or blind sectors.
multiple target echoes.
increased detection ranges.
The requirements for using radar for collision avoidance are described in ....
International Regulations for Prevention of Collisions at Sea.
Marine Orders Part 21.
Radar Manual Vol. 2.
Admiralty List of Radio Signals.
Clutter echoes are not usually caused by ....
hail.
rain.
fog.
snow.
Sea clutter is caused by reflections from ....
small craft and buoys.
areas of precipitation.
the sides of waves.
the blank surface of the sea.
The radar transceiver must be ....
directly underneath the scanner.
on the fore-and-aft line of the vessel.
as close to the power supplies as possible.
at a safe distance from the magnetic compass.
If possible the radar display should be sited ....
so that it is on the fore-and-aft line.
as far forward as possible in the ship.
as close as possible to the compass.
so it can be viewed facing forward.
Sub-refraction commonly occurs where ....
upper air disturbances are common.
strong winter gales are common.
a warm air layer lies over a cold sea surface.
a cold air layer lies over a warm sea surface.
The magnetron is sited in the ....
power supply unit.
scanner unit.
display unit.
transceiver unit.
Second trace echoes appear on the radar display at ....
false ranges on the correct bearing.
false bearings at the correct range.
correct ranges and bearings.
false ranges and bearings.
An operational check you should carry out when a radar set is installed is to ....
measure the frequency of the magnetron.
check the adjustment of the parallel index.
measure the duration of pulse length.
check the accuracy of the heading marker.
An operation check required on installation is to ....
measure the frequency of the local oscillator.
measure the peak power output.
determine the length of waveguide.
determine the limits of shadow sectors.
A radar log should record ....
the details of ships' power supplies.
a listing of radar aids to navigation.
the procedure for regular maintenance routines.
the details of repairs and services carried out.
Sea clutter echoes appear on the radar screen as ....
a mass of small echoes with an irregular shape.
a group of echoes at a constant range.
a mass of small echoes around the screen centre.
a group of echoes within a shadow sector.
Radar maintenance should be carried out in accordance with procedures in the ....
ship's log.
radar log.
safety manual.
operator's manual.
The bright spot which forms the trace or time base moves across the radar screen at a speed equivalent to ......
the speed of the radar waves.
half the speed of the radar waves.
twice the speed of the radar waves.
a continuously variable speed.
Second trace echoes are more likely to occur when ....
a long pulse length is used.
a short pulse length is used.
a low PRF is used.
a high PRF is used.
Multiple radar echoes are caused by ....
reflections from the surface of the sea.
reflection between own ship and a large close target.
reflections from the side lobes of the radar beam.
reflection from an obstruction on your own ship.
Side echoes appear on the radar display as .....
echoes in shadow sectors.
a line of echoes on one bearing.
lines radiating from the centre.
a symmetrical arc of echoes.
When side echoes are displayed, the true target echo will appear .....
at the edge of the pattern.
at the centre of the pattern.
closer than the false echoes.
farther than the false echoes.
Indirect echoes are caused by reflections from .....
targets directly ahead.
the surface of the sea.
targets on the beam.
obstructions close to the scanner.
Indirect echoes appear on the display ....
on the true range, but on a false bearing.
on a false range and bearing.
on the true bearing, but at a false range.
on the true range and bearing.
Multiple echoes appear on the screen ....
on a false bearing and range.
on the correct bearing but half the true range.
on the correct range but a false bearing.
on the correct bearing at double the true range.
Sub-refraction is likely to result in ....
reduced target detection ranges.
increased target detection ranges.
inaccurate detection range.
no effect on detection ranges.
The most common cause of radar interference is ....
electromagnetic storms or disturbances.
the power of radar transmissions from your own ship.
other radar transmissions on a similar frequency.
defective electrical equipment on the ship experiencing interference.
Under Rule 5; the radar should be used for keeping a proper lookout ....
whenever it may help.
when the radio is unserviceable.
during night-time hours.
when the background lights obscure visibility.
If your radar suffers from shadow sectors you should ....
consult your operator's manual.
warn approaching vessels in fog.
determine and record their limits.
report the fact to your marine authority.
The cause of shadow or blind sectors is ....
rough weather conditions.
side lobes of the radar beam.
obstructions on your own ship.
electromagnetic interference.
Super-refraction is most likely to cause ....
decreased target detection ranges.
no effect on detection ranges.
increased target detection ranges.
inaccuracies in detection range.
Super-refraction is normally caused by ....
strong winds.
cool air over a warm sea surface.
disturbances in the upper atmosphere.
warm air over cool sea surface.
When ducting occurs, the radar beam is ....
bent upwards.
affected by sunspot activity.
affected by the duration of daylight.
carried for long distances.
Ducting of the radar beam is caused by ....
conditions mild sub-refraction conditions.
mild super-refraction conditions.
extreme sub-refraction conditions.
extreme super-refraction.
Multiple echoes can be recognised because they appear ....
at constant range intervals.
around the arc of a circle.
on a false bearing.
along a curved line.
A radar presentation feature which is useful in radar pilotage is ....
relative motion.
fixed play centre.
radar shadow sector determination.
true motion.
Clutter echoes are often caused by ....
rain.
smoke and haze.
dust storms.
sand storms.
The best land target to use for a radar bearing is ....
a coastal indentation.
a large headland.
a sloping foreshore.
a small isolated feature.
When choosing objects for position fixing by radar ranges you should, if possible, avoid ....
steep faced features.
sloping land features.
small isolated features.
large prominent features.
A radar presentation feature which can often be used to advantage for position fixing is ....
an unstabilised presentation.
relative motion.
beamwidth distortion.
an off-centred display.
Low and sandy beaches should be avoided if possible when position fixing by radar because of ....
low accuracy.
high visibility.
strong tidal currents.
The use of radar ranges in preference to radar bearings for position fixing is because ....
they are quicker to take.
they are easier to take.
suitable targets are easier to find.
they are more accurate.
The technique used in radar pilotage for continuously monitoring a vessel's position is called ....
presentation unstabilisation.
parallel indexing.
cross indexing.
presentation stabilization.
The preferred method of radar position fixing for greatest accuracy is ....
taking several radar bearings.
taking several radar ranges.
taking a radar range and radar bearing.
taking a radar range and visual bearing.
When using the radar for coastal position fixing the main concern is to ....
allow for beamwidth distortion.
avoid radar interference.
obtain the most accurate fix.
avoid radar shadow effect.
On a radar display, the return from a racon ....
is transmitted continuously.
cannot be seen during hours of darkness.
cannot be seen in a clutter area.
gives a distinctive echo on the display.
The signal from a racon ....
only provides bearing data.
does not provide identification.
enables the beacon to be identified.
only provides range data.
The principle of a racon is that it ....
transmits continuously on X band.
transmits at fixed time intervals.
transmits when activated by an operator.
transmits on receipt of ship's radar pulse.
Radar reflectors are fitted to some buoys and small craft in order to ....
provide positive identification.
make them better radar targets.
avoid mutual radar preference.
obtain more accurate ranges.
What is the closest point of approach of target A?
Between 4-5 miles.
Between 1-2 miles.
Between 3-3,9 miles.
Less than 0,9 mile.
The technique of parallel indexing is usually used when navigating .....
a rotatable mask mounted on the display and marked with parallel lines.
a selsyn generator on the scanner.
a T/R cell in the waveguide.
transistors in parallel in the transceiver.
A basic radar plot can be used to ....
indicate target's most likely action.
obtain the rate of change of aspect.
determine the effect of own ship proposed avoiding action.
estimate the speed of target.
A vessel fitted with an operational radar must use it under Rule 6 to ....
help determine safe speed in prevailing conditions.
assess the course and speed of other vessels.
ensure compliance with traffic separation schemes.
identify itself to approaching vessels.
Under Rule 7, proper use of radar to determine risk of collision includes ....
use of true motion to determine target movement.
short range scanning for small targets.
correct use of anti-clutter controls.
radar plotting or equivalent systematic observation.
In restricted visibility, risk of collision can best be assessed by ....
listening for the target's sound signals.
posting additional lookouts.
watching the target's radar bearing and range.
establishing radio communication with the target.
Under Rule 19, if you get into a close quarters situation with a vessel forward of the beam in restricted visibility, you must ....
activate a second radar, if fitted.
reverse your engine until all way is lost.
post a forward lookout.
navigate with caution until danger of collision is over.
Rule 19 says that, if you detect another vessel by radar alone, you must ....
determine if risk of collision exists.
switch to manual steering.
maintain a steady course and speed.
continue to observe the other vessel.
The best land target to use for radar ranging is ....
a cliff face.
an edge of land.
a low-lying point.
a small rock.
To establish additional target data other than the Closest Point of Approach on a relative plot, you must ....
extend the target's relative track.
plot your own future track.
draw a line perpendicular to the target's track.
draw a relative velocity triangle.
A target with a «rough» surface is likely to ......
give a good echo at any aspect.
give only a very weak echo.
appear very smooth to a 3 cm radar.
reflect all the energy in one direction.
An ARPA is an ....
Additional Radar Pilotage Assignment.
Actual Radar Position Analyser.
Anti-collision Radar Performance Aid.
Automatic Radar Plotting Aid.
There is a risk of collision with another vessel if ....
her bearing is steady and the range is decreasing.
her bearing is changing and the range is increasing.
her bearing is steady and the range is increasing.
her bearing is changing and the range is decreasing.
The alteration of own ship's course or speed required to give a desired Closest Point of Approach (CPA) can be obtained from the ....
ship's data book.
radar tables.
collision rules.
radar plot.
A true motion radar display shows ....
a target's actual movement.
a target's movement relative to own ship.
own ship's movement relative to own ship.
a target stopped at the screen centre.
Positions obtained by radar ....
should only be used in restricted visibility.
cannot be relied on for navigation.
should be used independently of other aids.
should be checked by other available means.
An aid to identifying land features at long range is ....
a chart with topographic details.
the echo-ranging principle.
a reflection plotter.
the use of varying pulse lengths.
Using relative motion display mode, a plot of successive positions of a target at timed intervals enables you to assess ....
it's closest point of approach (CPA).
it's true speed.
it's aspect.
it's true course.
Echoes from rain can be reduced using the ....
tuning control.
brilliance control.
STC control.
differentiator control.
Side echoes are caused by reflections from ....
the obstruction in the path of the scanner.
the surface of the sea.
the side of your own vessel.
the side lobes of the radar beam.
The purpose of the anodes in the CRT (Cathode Ray Tube) is to ....
attract the electrons to the screen.
repel the electrons away from the screen.
control the brightness of the image.
The trace on the display rotates ....
at half the speed of the scanner.
at twice the speed of the scanner.
independently of the scanner.
in synchronization with the scanner.
The purpose of the gain control is to adjust ....
the amplification of the target echoes.
the brightness of the display control.
the frequency of the local oscillator.
the sharpness of the display focus.
On a radar display, this symbol identifies the ....
tuning control.
focus control.
brilliance control.
gain control.
The commonest type of radar scanner is the ....
horizontal slotted waveguide.
tilted parabolic cylinder.
double cheese.
single cheese.
If the trace is not correctly centred, error may occur when ....
measuring bearings.
measuring ranges.
using the tuning control.
using the gain control.
The function of the waveguide is to ....
block the transmitter during reception.
generate the RF pulses.
shape the beam in vertical plane.
conduct pulses to and from the scanner.
Altering the range scale may automatically change the ....
pulse length.
amplification of echoes.
anti-clutter settings.
transmitted frequency.
The distance of a target can be measured by using the ....
tuning control.
STC control.
range scale switch.
variable range marker.
An alternative name for the anti-rain clutter control is the ....
FTC control.
shift control.
swept gain control.
STC control.
The purpose of the bearing cursor is to ....
show the course of own ship.
align the heading marker.
indicate the direction of true north.
measure the bearing of targets.
The gain control should be adjusted so that ....
there is a light speckled background on the screen.
no clutter echoes are showing on the screen.
clutter echoes are showing at maximum strength.
the screen background has no speckling.
Before taking target bearings, you should check that ....
the gain control is set to zero.
the heading marker is switched off.
the Variable Range Marker (VRM) is switched on.
the trace is correctly centred.
The tuning control adjusts ....
the frequency of the local oscillator.
the amplification of target echoes.
the amplification of power output.
the transmitted frequency.
The number of cycles of a radio wave which pass a fixed point in a given time is called the ....
amplitude.
speed.
wavelength.
frequency.
The purpose of radar is to enable ....
the range and bearing of objects to be obtained.
the echoes of targets to be separated.
the wave-lengths of radio waves to be calculated.
the speed of radio waves to be measured.
Radar does not transmit continuously because it would ......
cause interference to other vessels.
reduce the life of components.
make the equipment get very hot.
prevent detection of targets.
Target ranges are obtained from ......
the range marker.
the pulse repetition frequency.
the heading marker.
the bearing marker.
To provide accurate target bearings the radar beam must be ......
narrow in the vertical plane.
wide in the horizontal plane.
narrow in the horizontal plane.
wide in the vertical plane.
Accurate target bearings are obtained by ......
making the radar beam wide horizontally.
rotating the trace intermittently.
synchronizing the radar beam and the trace.
making the radar beam wide vertically.
Weaker echoes are converted to signals of detectable strength by the ....
local oscillator.
mixer crystals.
IF amplifier.
limiter circuit.
Half the vertical distance between the crest and the trough of a radio wave is called .....
the amplitude.
the frequency.
a cycle.
the wavelength.
This symbol identifies the ....
heading marker alignment.
centering control.
range scale control.
scanner rotating.
A radar with a wavelength of 3,2 cm would have a frequency of about ....
3,245 MHz.
12,450 MHz.
6,060 MHz.
9,375 MHz.
S-band radar has a wavelength of ....
5,0 to 5,4 cm.
3,1 to 3,2 cm.
9,2 to 10 cm.
12,5 to 12,9 cm.
Marine radar wavelengths are measured in .....
megahertz.
microseconds.
feet per second.
centimetres.
The transmitted frequency is determined by the design of the ....
scanner.
waveguide.
T/R cell.
magnetron.
The main component of the transmitter is the ....
magnetron.
power supply.
antenna.
cathode ray tube.
The magnetron sends the RF pulses to the ....
receiver unit.
display unit.
transmitter unit.
scanner unit.
The horizontal distance between the adjacent crests of a radio wave is called ....
the wavelength.
the amplitude.
a cycle.
the frequency.
The distance of the radar horizon is largely determined by ......
the width of the scanner.
the amount of cloud cover.
the state of the sea surface.
the downward refraction of radar waves.
Range discrimination depends mainly on which of the following?
Pulse length.
Pulse repetition frequency.
Scanner rotation speed.
Transmitted frequency.
Radar bearing discrimination depends mainly on which of the following?
Transmitted frequency.
Horizontal beamwidth.
Pulse length.
Scanner rotation speed.
Radar bearing discrimination is the ability to display separately ....
two targets on same bearing at slightly different ranges.
two targets at same range on slightly different bearings.
two targets at slightly different range and bearings.
two targets on same bearing at same range.
The horizontal pattern of a radar beam consists of ......
one large lobe and smaller side lobes either side.
one lobe.
one small lobe and two larger lobes.
a number of lobes of similar size.
Radar bearing discrimination should be within .....
1,0 degrees.
2,5 degrees.
1,5 degrees.
2,0 degrees.
This display symbol shown is for ....
relative motion.
north-up presentation.
true motion.
head-up presentation.
A typical figure for minimum radar range is .....
50 metres.
25 metres.
100 metres.
75 metres.
Which of the following has most effect on the size and shape of small radar targets?
Scanner height.
Pulse length.
Scanner rotation speed.
Pulse repetition rate.
A radar target of a certain size is likely to give a stronger echo if it is made of .....
fibreglass.
wood.
metal.
canvas.
Radar targets give the strongest echoes if they are .....
soft and porous.
made of wood.
poor electrical conductors.
hard and dense.
A radar target is likely to give the poorest reflection if its shape is .....
cylindrical.
a perpendicular plane.
conical.
can-shape.
The principle of a corner reflector is that it .....
changes the direction of the beam by 90 degrees.
scatters the beam uniformly through 360 degrees.
deflects the beam clear of obstructions.
changes the direction of the beam by 180 degrees.
A corner reflector is used to .....
increase the detectability of small targets.
detect targets below the radar horizon.
enable the radar to examine shadow areas.
increase the radar power output.
What is the closest point of approach of target A?
Between 1-2 miles.
Less than 0,9 miles.
Between 2-2,2 miles.
Between 3-3,9 miles.
The vertical beam must be wide enough to allow for the .....
the size of large targets.
reduction of sea clutter.
elimination of shadow sectors.
rolling and pitching of the ship.
One cause of bearing error is ....
use of an unsuitable Pulse Repetition Frequency (PRF).
misalignment of the centre of the trace on the display.
inaccuracy of the fixed range ring.
scanner mounted too far forward.
A target with a smooth surface will only give a good echo if its aspect relative to the direction of the radar beam is .....
30 degrees.
60 degrees.
45 degrees.
90 degrees.
The tuning control is best adjusted by using the ....
centring control.
visual tuning indicator.
power monitor.
range scale control.
The symbol shown here identifies the ....
range scale control.
north-up presentation.
heading marker alignment control.
head-up presentation.
An alternative name for the anti-sea clutter control is the ....
FTC control.
radar on/off switch.
differentiator.
STC control.
As distance from the scanner increases, the power of the radar beam ....
decreases rapidly.
remains constant.
decreases slowly.
increases slowly.
Horizontal beamwidth depends mainly on ....
transmitted power.
waveguide cross-section.
scanner width.
PRF.
Radar range discrimination should not be less than ......
25 metres.
100 metres.
50 metres.
75 metres.
Bearing accuracy depends mainly on ....
scanner rotation speed.
pulse length.
spot size.
horizontal beamwidth.
Which of the following has the most effect on the definition of a small target on the radar display?
Horizontal beamwidth.
Scanner rotation speed.
Accuracy of range markers.
Pulse repetition rate.
Compared to the visual horizon, the radar horizon is ....
about 3 % nearer.
about 6 % nearer.
about 3 % further away.
about 6 % further away.
Maximum radar range depends partly on the ....
mixer strength.
size of the spot.
peak power output.
scanner rotation speed.
A factor in determining a radar maximum range is ......
spot size.
heading marker alignment.
receiver sensitivity.
linearity of timebase.
Minimum radar range depends mainly on ......
vertical beamwidth.
receiver sensitivity.
scanner height.
pulse length.
Radar range accuracy should be within ......
3,5 % of the range scale in use.
1,5 % of the range scale in use.
0,5 % of the range scale in use.
2,5 % of the range scale in use.
The effect of the anti-rain clutter control is to ....
reduce the strength of all echoes.
reduce the strength of close range echoes.
reduce the size of close range echoes.
reduce the size of all echoes.
Vertical beamwidth is determined by ....
the height of the scanner.
the design of the scanner.
the transmitted wavelength.
the number of slots in the scanner.
What is the closest point of approach of target A?
Between 2-4 miles.
Less than 1 mile.
Between 4-5 miles.
Between 1-2 miles.
What is the closest point of approach of target B?
More than 5 miles.
Between 4-5 miles.
Less than 1 mile.
Between 1-2 miles.
What is the time of closest point of approach of target A?
Between 11-20 minutes.
Between 21-30 minutes.
Now or passed.
Between 31-45 minutes.
Which target will have the closest point of approach?
Target E.
Target D.
Target F.
Target B.
What is the time of closest point of approach of target B?
Now or passed.
Between 11-20 minutes.
Between 31-45 minutes.
Between 21-30 minutes.
What is the closest point of approach of target A?
Now or passed.
Less than 0,9 mile.
Between 1-2 miles.
Between 4-5 miles.
Which target will have the closest point of approach?
Target B.
Target C.
Target D.
Target A.
What is the aspect of the target B?
Starboard beam. (Green 75-105).
Port beam. (Red 75-105).
Starboard bow. (Green 15-75).
Port bow. (Red 15-75).
What is the ability of a radar set to clearly distinguish two targets, on the same range and slightly different bearings, as two separate targets on the PPI, known as?
Bearing discrimination.
Minimum range.
Maximum range.
Range discrimination.
What are 3 cm radars called?
L band.
S band.
M band.
X band.
What is the typical amount of time an ARPA would take to process and predict data?
10 to 20 min.
20 to 30 min.
5 to 10 min.
1 to 3 min.
Sometimes shipboard obstructions such as masts, funnels etc reflect radar energy and the echo painted on the PPI shows a different direction but the same range. What is this type of echo known as?
Multiple echo.
Indirect echo.
Side lobe echo.
Second trace echo.
What is the effect of a radar reflector on a buoy?
It weakens the reflectivity of the target.
It acts as a ramark.
It is used to provide a unique signal.
It strengthens the reflectivity of the target.
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.
North at 15 knots.
Stationary.
South at 7 1/2 knots.
What is the time of closest point of approach of target A?
Now or passed.
Between 21-30 minutes.
Between 46-60 minutes.
Between 31-45 minutes.
Which target will have the closest point of approach?
Target C.
Target A.
Target B.
Target D.
What will be the closest point of approach of target A?
Less than 0,9 miles.
Between 2-2,2 miles.
Between 3-3,9 miles.
Between 1-2 miles.
What is the time of closest point of approach of target A?
Between 46-60 minutes.
Now or passed.
Between 21-30 minutes.
Between 31-45 minutes.
What is the closest point of approach of target A?
Between 1-2 miles.
Between 3-4 miles.
Less than 0,9 miles.
Between 2-2,9 miles.
What is the aspect of the target B?
Starboard bow. (Green 15-75).
Port beam. (Red 75-105).
Starboard beam (Green 75-105).
Port bow. (Red 15-75).
What is the closest point of approach of target A?
Between 2-2,9 miles.
Now or passed.
Between 1-2 miles.
Between 3-3,9 miles.
Which target will have the closest point of approach?
Target A.
Target B.
Target C.
Target E.
What type of refraction will be experienced, when a cold breeze blows over a relatively warm sea?
Sub-refraction.
Super-refraction.
No refraction.
Standard refraction.
What is the closest point of approach of target C?
Between 4-5 miles.
More than 5 miles.
Between 0,5-1,5 miles.
Between 2-2,9 miles.
What is the time of closest point of approach of target C?
Now or passed.
Between 0-10 minutes.
Between 21-30 minutes.
Between 31-45 minutes.
What is the aspect of the target C?
Stern or nearly astern.
End on or nearly end on.
Port bow. (Red 15-75).
Starboard bow. (Green 15-75).
If the visibility is restricted, what action should be taken in this situation?
A broad alteration to port.
A broad alteration of course to starboard.
A substantial reduction of speed.
Stand on with caution.
What is the closest point of approach of target B?
Now or passed.
Between 3-4 miles.
Less than 1 mile.
Between 1-2 miles.
Which target will have the closest point of approach?
Target B.
Target C.
Target D.
Target A.
What is the time of closest point of approach of target B?
Now or passed.
Between 31-45 minutes.
Between 11-20 minutes.
Between 21-30 minutes.
After changing range scales on which the ARPA facilities are available, or resetting the display, in what period of time should full plotting information be displayed?
A period of time not exceeding ten scans.
A period of time not exceeding twelve scans.
A period of time not exceeding four scans.
A period of time not exceeding fourteen scans.
What measures may be taken to minimize dangers from blind spots?
Frequent change of PRF from low to high and vice versa and observing results on the screen.
Relying solely on visual observation.
Increasing the speed of the vessel.
Using only radar information without visual checks.
Which of these factors would cause blind sectors on the PPI?
The beam of radar energy is obstructed by a mast.
The scanner speed is a little slower than normal.
Too much vibration.
Other transmissions taking place at the same time.
On which of these factors does bearing resolution depend?
Peak power of the set.
VBW.
HBW.
PRF.
What is the term for the number of pulses sent out by the scanner in one second?
Pulsation.
Pulse length.
Pulse repetition frequency.
Pulse width.
Your vessel, going E at 10 kts, observed by radar a vessel going W at 10 kts, what will be the approximate direction and rate at which the pip (picture in picture) would move on your PPI (plan position indicator) scope?
West at 20 knots.
East at 20 knots.
West at 10 knots.
Stationary.
When two tracked targets are very close to each other, the radar data of one target shifts over to the other target. What is this called?
Target loss.
Trial manoeuvre.
Target swap.
Plotting.
When obtaining a fix by radar only, which is more accurate?
A fix obtained by cross bearings.
A fix obtained by bearing and range.
The intersection of the arcs obtained using the ranges from the objects as radii.
All of the other options are equally accurate.
What is the rate at which two moving objects approach or separate from each other called?
Relative movement.
Relative distance.
Relative speed.
Relative bearing.
What type of spurious echoes are these? (see figure)
Indirect echo.
Side lobe echo.
Multiple echo.
Second trace echo.
What does the diagram indicate? (see figure)
Range discrimination.
VBW.
Bearing discrimination.
Minimum range.
Which part of the radar is a high power RF oscillator capable of being switched on and off for short durations at the desired PRF, by the pulses from the modulator?
TR cell.
Local oscillator.
Mixer.
Magnetron.
What is this mark? (see figure)
Signal from SART.
Ramark.
Lt vessel.
Racon.
Which are the two most important pieces of input information required to operate the ARPA accurately?
Position and GMT time.
Heading and GMT time.
GMT time and speed.
Speed and heading.
What is no. 12? (see figure)
Scanner.
Mixer.
Trace blanking.
CRT.
What is the vertical angle between the upper and lower edges of the radar beam?
Horizontal band width.
Vertical band width.
Vertical beam width.
Horizontal beam width.
What is the time of closest point of approach of target B?
Now or passed.
Between 0-10 minutes.
Between 21-30 minutes.
Between 11-20 minutes.
Which of these gives only a bearing and not a range?
Racon.
Buoy.
Lt vessel.
Ramark.
Which control on the radar is used to suppress clutter?
Gain.
Tuning.
Differentiator.
Anti-clutter.
Regarding performance standards for navigational radar, what should be the bearing accuracy?
Plus or minus 2 deg.
Plus or minus 2 1/2 deg.
Plus or minus 1 deg.
Plus or minus 1/2 deg.
What should be the size of the display on which ARPA information with alphanumerical data area around it is presented?
Display diameter should be at least 300 mm.
Display diameter should be at least 250 mm.
Display diameter should be at least 200 mm.
Display diameter should be at least 340 mm.
How does height above sea level influence the range of detection of a target?
Higher objects are detected further away than lower objects.
Higher objects are detected at a lesser distance than lower objects.
Higher objects are detected at the same distance as lower objects.
Higher objects are sometimes never detected whereas lower objects at the same range are always detected.
What is VRM on marine radars?
Variable Range Marker.
Visual Radar Measurement.
Velocity Reference Marker.
What is used to warn the observer if any distinguishable target closes to a chosen range or transits a zone chosen by the observer?
Guard rings and zones.
CPA warnings.
Target lost warning.
Collision course warning.
The detection range of surface targets is decreased when radar waves touch the earth's surface at a point closer than the standard horizon. What type of refraction is this?
Normal refraction.
Ducting.
Super refraction.
Sub refraction.
Which of these range scales would you use in a congested channel?
18 miles.
1 to 6 miles.
12 miles.
24 miles.
What should be the performance standards of a radar so that it should function without deterioration in performance when the vessel is rolling or pitching?
Upto +/-20 deg Rolling or pitching.
Upto +/-30 deg Rolling or pitching.
Upto +/-25 deg Rolling or pitching.
Upto +/-10 deg Rolling or pitching.
Which are the four main elements of a radar system?
Transmitter, servo link, target, display.
Transmitter, antenna, receiver, display.
Transmitter, servo link, antenna, target.
Transmitter, servo link, antenna, display.
What are 10 cm radars called?
L band.
X band.
M band.
S band.
Which of these controls is provided to check the overall efficiency of the radar?
Centre shift.
Performance monitor.
Range selector.
Pulse length selector.
Atmospheric density gradients bend radar rays as they travel to and from target. How this is called?
Reflection.
Diffraction.
Refraction.
What is used to control the amplification of echoes received?
Focus.
Brilliance.
Differentiator.
Gain.
What is the closest point of approach of target A?
Between 3-3,9 miles.
Between 1-2 miles.
Less than 0,9 mile.
Between 4-5 miles.
Which target will have the closest point of approach?
Target C.
Target E.
Target F.
Target B.
What is the closest point of approach of target A?
Between 4-5 miles.
Less than 1 mile.
More than 5 miles.
Between 1-2 miles.
What is the closest point of approach of target A?
Now or passed.
Between 3-3,9 miles.
Between 1-2 miles.
Between 2-2,9 miles.
What is the closest point of approach of target A?
Between 2-4 miles.
Between 1-2 miles.
Less than 1 mile.
Between 4-5 miles.
What is the closest point of approach of target A?
Between 4-5 miles.
Less than 1 mile.
Between 1-2 miles.
Between 2-4 miles.
What is the time of closest point of approach of target A?
Between 21-30 minutes.
Between 0-10 minutes.
Between 31-40 minutes.
Between 11-20 minutes.
What is the closest point of approach of target A?
Between 4-5 miles.
Between 2,1-3,9 miles.
Less than 0,9 miles.
Between 1-2 miles.
What is the closest point of approach of target A?
Less than 0,9 miles.
Between 4-5 miles.
Between 2,1-3,9 miles.
Between 1-2 miles.
What is the closest point of approach of target C?
Between 2-4 miles.
More than 5 miles.
Less than 0,9 miles.
Between 4-5 miles.
What is the time of closest point of approach of target C?
Now or Passed.
Between 31-45 minutes.
Between 5-15 minutes.
Between 20-30 minutes.
Which target will have the closest point of approach?
Target C.
All Equal.
Target A.
Target B.
What is the closest point of approach of target C?
Less than 0,9 miles.
Between 4-5 miles.
Between 2-4 miles.
More than 5 miles.
What is the closest point of approach of target B?
Between 4-5 miles.
Between 2-4 miles.
Less than 1 mile.
Between 1-2 miles.
Which target will have the closest point of approach?
Target A.
Target B.
All equal.
Target C.
What is the closest point of approach of target A?
Between 4-5 miles.
Between 2-4 miles.
Less than 1 mile.
Between 1-2 miles.
What is the closest point of approach of target A?
Between 2-3 miles.
Less than 0,9 miles.
Between 3-3,9 miles.
Between 4-5 miles.
What is another name for a calibration ring?
Adjustable measurement loop.
Calibration disk.
Fixed electronic range.
Standard reference circle.
What will be the closest point of approach of target A?
Between 4-5 miles.
Less than 0,9 miles.
Between 1-2 miles.
Between 3-3,9 miles.
What is the closest point of approach of target A?
Between 3-3,9 miles.
Between 4-5 miles.
Less than 0,9 miles.
Between 2-3 miles.
What is the closest point of approach of target A?
Between 4-5 miles.
Between 3-3,9 miles.
Less than 0,9 miles.
Between 1-2 miles.
What is the closest point of approach of target A?
Less than 1 mile.
Between 1-2 miles.
Between 2-4 miles.
Between 4-5 miles.
What is the aspect of the target A?
Starboard quarter (Green 105-160).
Port bow (Red 15-75).
Port quarter (Red 105-160).
Starboard bow (Green 15-75).
What is the closest point of approach of target B?
Between 4-5 miles.
Between 2-4 miles.
Less than 1 mile.
Between 1-2 miles.
What is the closest point of approach of target A?
Between 1-2 miles.
Between 4-5 miles.
More than 5 miles.
Less than 0,9 mile.
What is the time of closest point of approach of target A?
Between 21-30 minutes.
Between 11-20 minutes.
Now or passed.
Between 31-45 minutes.
What is the aspect of the target A?
Port bow (Red 15-75).
Starboard bow (Green 15-75).
Starboard quarter (Green 105-160).
Port quarter (Red 105-160).
What is the closest point of approach of target A?
Between 4-5 miles.
Between 2-3 miles.
Between 3-3,9 miles.
Less than 0,9 miles.
What is the closest point of approach of target A?
Between 3-3,9 miles.
Between 4-5 miles.
Less than 0,9 mile.
Between 1-2 miles.
What is the time of closest point of approach of target A?
Now or passed.
Between 31-45 minutes.
Between 21-30 minutes.
Between 46-60 minutes.
Which target will have the closest point of approach?
Target E.
Target C.
Target B.
Target D.
Which target will have the closest point of approach?
Target F.
All the same.
Target D.
Target B.
Which target will have the closest point of approach?
Target B.
Target A.
Target D.
Target C.
Which target will have the closest point of approach?
Target B.
Target D.
Target E.
Target F.
What is the aspect of the target B?
Starboard bow. (Green 15-75).
Port beam. (Red 75-105).
End on or nearly end on.
Port bow. (Red 15-75).
Which target will have the closest point of approach?
Target B.
Target A.
Target D.
Target F.
What is the closest point of approach of target C?
Between 4-5 miles.
Less than 1 mile.
Between 1-2 miles.
Between 2-3 miles.
What is the time of closest point of approach of target B?
Between 0-10 minutes.
Now or passed.
Between 31-45 minutes.
Between 15-30 minutes.
What is the aspect of the target C?
Starboard bow. (Green 15-75).
Starboard beam (Green 75-105).
Port beam. (Red 75-105).
Port bow. (Red 15-75).
What is the closest point of approach of target B?
Between 2-2,9 miles.
Between 3-3,9 miles.
Less than 0,9 mile.
Between 1-1,9 miles.
Which target will have the closest point of approach?
Target C.
Target E.
Target D.
Target A.
What is the closest point of approach of target B?
More than 4 miles.
Between 3-4 miles.
Less than 1 mile.
Between 1-2 miles.
What is the closest point of approach of target A?
Between 1-2 miles.
Between 2-3 miles.
Between 3-3,9 miles.
Less than 1 mile.
What is the time of closest point of approach of target A?
Now or passed.
Between 11-20 minutes.
Between 46-60 minutes.
Between 31-45 minutes.
Which target will have the closest point of approach?
Target B.
Target A.
Target D.
Target C.
What is the closest point of approach of target B?
Between 4-5 miles.
More than 5 miles.
Between 3-3,9 miles.
Between 1-2 miles.
Which target will have the closest point of approach?
Target B.
All Equal.
Target A.
Target C.
What is the time of closest point of approach of target A?
Between 21-30 minutes.
Now or passed.
Between 31-45 minutes.
Between 11-20 minutes.
What is the time of closest point of approach of target C?
Between 20-30 minutes.
Between 5-15 minutes.
Between 31-45 minutes.
Now or Passed.
Which target will have the closest point of approach?
All Equal.
Target B.
Target A.
Target C.
What is the closest point of approach of target C?
Between 4-5 miles.
Less than 1 mile.
Between 1-2 miles.
Between 2-3 miles.
Which target will have the closest point of approach?
Target A.
All equal.
Target C.
Target B.
What is the closest point of approach of target B?
Between 3-3,9 miles.
Less than 0,9 mile.
Between 1-1,9 miles.
Between 2-2,9 miles.
Which target will have the closest point of approach?
All Equal.
Target B.
Target A.
Target C.
What will be the closest point of approach of target B?
Between 1-2 miles.
Between 4-5 miles.
Less than 0,9 mile.
Between 3-4 miles.
If the visibility is 10 miles, what action should be taken?
A broad alteration to starboard.
A broad alteration to port.
Stand on.
A substantial reduction of speed.
Which target will have the closest point of approach?
All the same.
Target C.
Target A.
Target B.
Which target will have the closest point of approach?
All the same.
Target A.
Target B.
Target C.
What is the closest point of approach of target C?
Between 1-2 miles.
Between 4-5 miles.
Less than 0,9 mile.
Between 3-4 miles.
What is the time to closest point of approach of target C?
Now or passed.
Between 31-45 minutes.
Between 46-60 minutes.
Between 21-30 minutes.
Which target will have the closest point of approach?
All the same.
Target C.
Target A.
Target B.
