RADAR TRANSMISSION - EXERCISES TWO.............. NAME:_________________

1. The main difference between an analogue radar and a rasterscan radar is:

(a) the transmitter

(b) the display

(c) the aerial

 

 

 

2. The most common type of scanner is:

(a) titled parabolic waveguide

(b) horizontal slotted waveguide

(c) rounded parabolic

 

 

 

3. The transmitted PRF is determined by the action of:

(a) magnetron

(b) trigger unit

(c) modulator

 

 

 

4. The transmitted pulse length is determined by the action of:

(a) magnetron

(b) trigger unit

(c) modulator

 

 

 

5. Which of the following would give the poorest echo:

(a) a wooden yacht

(b) a ferro-cement yacht

(c) a fibreglass yacht

 

 

 

6. A target to starboard 7° visually and dead ahead on the radar, is incorrectly positioned because:

(a) parallax error

(b) radar aerial not on centreline

(c) heading marker misaligned

 

 

 

7. The true range of a racon beacon compared to the racon paint is:

(a) in front of the paint

(b) equal the nearest edge of the paint

(c) equal to the furthest edge of the paint

 

 

 

8. Super-refraction is normally caused by:

(a) disturbances in the upper atmosphere

(b) cool air layer over a warm sea surface

(c) warm air layer over a cooler sea surface

 

 

 

9. The vertical beam must be wide to allow for:

(a) detection of small targets

(b) reduction of the effect of sea clutter

(c) heavy rolling and pitching

 

 

 

10. A target gives the best echo when its aspect is:

(a) 60°

(b) 90°

(c) 45°

 

 

 

11. Bearing accuracy depends on:

(a) scanner rotation speed

(b) pulse length

(c) horizontal beam width

 

 

 

12. A characteristic of a racon beacon is that it:

(a) transmits continuously

(b) receives a pulse and then transmits its own pulse

(c) receives a pulse and then re-transmits the pulse

 

 

 

13.. The magnetron of a radar is located in which electronic section?

(a) IF amplifier

(b) transmitter

(c) ranging unit

 

 

 

14. The horizontal beamwidth is determined by the:

(a) oscillating transmitter

(b) tuning of the receiver

(c) scanner size

 

 

 

15. On a long range the operator should expect the pulse repetition frequency (PRF) to be:

(a) relatively high

(b) relatively low

(c) no change, PRF is not dependent on range scale

 

 

 

16. Selection of pulse length is done in which section of the radar?

(a) receiver

(b) IF amplifier

(c) transmitter

 

 

 

17. To increase the power of the transmitted pulse the operator should:

(a) increase gain

(b) adjust tuning

(c) change to long pulse

 

 

 

18. The principal advantage of a rasterscan display is that it:

(a) shows less clutter

(b) more accurate bearings

(c) allows daylight viewing

 

 

 

19. An interlaced rasterscan radar will?

(a) show a flicking screen image

(b) not show screen flicker

(c) display in colour

 

 

 

20. A basic principle of radar is that range is determined by:

(a) measurement of elapsed time between transmission of a pulse and reception of its echo

(b) measurement of elapsed time between transmission of a pulse striking a target

(c) counting the number of pulses striking a target

 

 

 

21. The beam from a marine radar scanner is:

(a) wide horizontally, narrow vertically

(b) narrow horizontally, wide vertically

(c) narrow horizontally, narrow vertically

 

 

 

22. The most important factor limiting target detection is:

(a) the overall performance of the radar set

(b) the height of the scanner

(c) the power of the transmitted pulse

 

 

 

23. Three centimetre radar operates on or about the following frequency:

(a) 9,3000 MHz

(b) 3,100 MHz

(c) 6,300 MHz

 

 

24. The presence of a known multiple echo suspected of obscuring the display of a near echo required to be observed can be removed by:

(a) careful adjustment of the tune control

(b) switching to short pulse

(c) careful adjustment of the gain and / or clutter controls

 

 

 

25. Sub-refraction conditions cause:

(a) a reduction in the range accuracy

(b) an increase in the detection range of targets

(c) a reduction in the detection ranges of targets

 

 

 

26. With a given rate of precipitation, the following meteorological condition will display the stronger clutter echoes on the display of a 3 cm radar:

(a) heavy snowstorm

(b) heavy rainstorm

(c) hail

 

 

 

27. Super-refraction can cause:

(a) an increase in the detection range of targets

(b) a reduction in the detection range of targets

(c) will not affect detection range of targets

 

 

 

ANSWERS:

1 b

2 b

3 b

4 c

5 c

6 c

7 b

8 c

9 c

l0 b

11 c

12 b

13 b

14 c

15 b

16 c

17 c

18 c

19 b

20 a

21 b

22 c

23 a

24 c

25 c

26 b

27 a