4.      The tuning control adjusts:

a)       the frequency of the receiver

b)      the brightness of the picture

c)       the power output

5.      When ducting occurs the radar beam:

a)       bent upwards to penetrate cooler air

b)      carried long distances between air layers

c)       bent downwards and reflected off the sea

6.      Indirect echoes are caused by reflections from:

a)       large close targets

b)      obstructions close to the scanner

c)       targets on the beam

7.      Minimum range depends mainly on:

a)       scanner height

b)      vertical beamwidth

c)       pulse length

8.      A vessel equipped with both a 10 cm and a 3 cm radar.  One would expect the 3 cm radar to provide better:

a)       range discrimination

b)      range

c)       attenuation

9.      The theoretical detection range of an object 81 metres high, from a ship with an aerial 16 metres above sea would be:

a)       29 miles

b)      27 miles

c)       21 miles

10.     A small GRP vessel is considered a poor radar target mainly because:

a)       GRP is transparent to radar energy

b)      GRP absorbs radar energy

c)       GRP reflects all the radar energy

11.    Range discrimination between two targets at about 8 miles on the display can be improved by:

a)       reducing gain

b)      reducing pulse length

c)             reducing tuning

12.    If an echo appears in a shadow sector you could check if it was a real echo by:

a)       reducing gain

b)      reducing brilliance

c)       altering course

13.    Increasing the sea clutter control:

a)       reduces echo strength from waves

b)      reduces amplification of close echoes

c)       blanks out the inner screen

14.    A rasterscan radar differs from a analogue radar in that:

a)       the screen is rectangular

b)      the screen is round

c)       the screen is coloured

15.      The figure below could be an example of:

a)       a multiple echo

b)      side echoes

c)       mutual interference

16.    The figure below is that used by the IMO to indicate:

a)       pulse length

b)      short pulse

c)       long pulse

17.    The figure below is that used by the IMO to indicate:

a)       true motion

b)      north-up

c)       ships head up

18.    The figure below is that used by the IMO to indicate:

a)       radar on

b)      scale illumination

c)       brilliance

c)            mutual interference

20.    The figure below is that used by the IMO to indicate:

a)       VRM

b)      pulse length

c)             range

21.    The figure below is that used by the IMO to indicate:

a)       VRM

b)      range

c)       transmitting

22.    A higher screen resolution would mean that the display would be:

a)       bigger

b)      sharper and clearer

c)       better focused

23.     LCD means;

a)       locally centred display

b)      local centralised display

c)       liquid crystal display

24.    A analogue radar differs from a rasterscan radar in that:

a)       the display must be viewed through a hood in daylight

b)      the display is coloured

c)       the display is green and black

25.    Altering the range scale may automatically change the:

a)       transmitted frequency

b)      pulse length

c)       amplification of echoes

26.    Radar uses pulse transmission in order to:

a)       conserve energy

b)      detect close targets

c)       avoid interference

27.    The figure below represents the radar display of a vessel steering 270°.  What type of display is it?

a)       north-up

b)      ship’s head-up

c)       true motion

28.     You have a radar target at a range of 7 miles on your starboard bow, when you hear a fog signal apparently forward of your beam.  You must:

a)       alter course to starboard immediately

b)      alter course to starboard and reduce speed to steerage speed immediately

c)       slow to mere steerage way

29.    You are in restricted visibility and have plotted a target on your starboard quarter and determined that the overtaking vessel will pass at a CPA of 0.2 miles on your port side.  You must:

a)       alter course to starboard to increase the CPA

b)      stop immediately

c)       alter course to port increase the CPA

30.    You are in restricted visibility and have plotted a target on your port bow and determined that the approaching vessel is on a collision course.  You must:

a)       allow the approaching give way vessel time to alter course

b)      alter course to port or reduce speed or stop

c)       alter course to starboard or reduce speed or stop

31.    You would expect rain to have a greater affect on a 3 cm radar than on a 10 cm radar:

a)       no

b)      yes

c)       no difference

32.    Your radar has a beam width of 4°, you measure the relative bearing of a large headland fine on the starboard bow to be 123° T.  What is the corrected bearing:

a)       123°

b)      125°

c)       121°

33.     Range discrimination is the ability of the radar to distinguish between two targets:

a)       on the same range but slightly different bearings

b)      on the same bearing but slightly different ranges

c)       on slightly different ranges and bearings

34.    Bearing discrimination is the ability of the radar to distinguish between two targets:

a)       on the same range but slightly different bearings

b)      on the same bearing but slightly different ranges

c)       on slightly different ranges and bearings

35.    Beam width distortion occurs because:

a)       radar waves are reflected

b)      the radar beam is wide vertically

c)       the radar beam is a finite width

36.    Side echoes are caused by:

a)       echoes from the side of waves

b)      echoes from the side lobes of the radar

c)       echoes from the sides of close vessels

37.    The strength or power of a radio wave is known as it’s:

a)       cycle

b)      amplitude

c)       wavelength

38.    A 10 cm radar transmits in the:

a)       x band

b)      q band

c)       s band

39.     Beam width distortion can be improved by:

a)       reducing the brilliance

b)      reducing the gain

c)       reducing the tuning

40.    The figure below is an example of:

a)       a SART

b)      radar spooling

c)             mutual interference

PART THREE: - To demonstrate on a radar simulator or on a vessel an ability to use radar for the safe navigation of a vessel and a ability to use radar as an aid to collision avoidance. You will need to use a plotting sheet.

1. You should have already completed the radar plotting assignment.

2.  Own vessel is in open waters on a course of 240° T, speed 8 knots in restricted visibility.  Two vessels are observed as follows:

Target A

0303:  bearing 200°, distance 5.8 miles

0307:  bearing 200 ½ °, distance 5.2 miles

0311:  bearing 201°, distance 4.6 miles

Target B

0300:  bearing 168°, distance 5.4 miles

0305:  bearing 169°, distance 5.1 miles

0310:  bearing 170°, distance 4.9 miles

a)            Find the CPA, TCPA, course, speed and aspect of other vessels.

b)            State what action if any you are going to take.

ANSWERS-

PART TWO:

1.      c

2.      b

3.      a

4.      a

5.      b

6.      b

7.      c

8.      a

9.      a

10.  a

11.  b

12.  c

13.  b

14.  a

15.  b

16.  b

17.  c

18.  b

19.  a

20.  c

21.  a

22.  b

23.  c

24.  a

25.  b

26.  b

27.  a

28.  c

29.  c

30.  c

31.  b

32.  b

33.  b

34.  a

35.  c

36.  b

37.  b

38.  c

39.  b

40.  c

CPA  0.45 nm
TCPA  0344
Course  309°
Speed  6.5 knots
Aspect  Green 72°

Target B

CPA 1.9 miles
TCPA 0440
Course 293°
Speed 7.5 knots
Aspect Green 88°

Action to take to increase CPA

Reduce speed to 4 knots to let both vessels pass ahead.