Navigational Aids [MITRC refresher]

1.        The phenomenon evidenced by the change in the observed frequency of a sound or a radio wave caused by the time rate of change in the magnitude of the radial component of relative velocity between the source and the point of observation.

1. Tunnel effect
2. Doppler effect
3. Gunn effect
4. End effect

2.        Power density is inversely proportional to the square of the distance from the source or transmitter to the destination or receiver. this is called

1. Coulomb’s law
2. Inverse square law
3. Lenz,s law
4. Maxwell’s law

3.        They are nondirectional transmitters and/or receivers that operate in the LF and MF bands.

1. Radio Beacons
2. DME
3. ILS
4. LORAN

4.        The ratio of the pulse width to the time between the beginning of two pulses is called

1. Doppler shift
2. Duty cycle
3. Tracking error
4. PRR

5.        When  the speed of a radio signal is known, radar can be used to determine the _____ of the target.

1. Range
2. Altitude
3. Direction
4. Doppler shift

6.        The elapsed time between a radiating radar signal and receiving its echo is 43.2 microseconds. The target distance is____ nautical miles.

1. 3.5
2. 4.5
3. 5.5
4. None of these

7.        The most commonly used component in a radar transmitter is the _______ tube.

1. Dynatron
2. Twystron
3. Magnetron
4. Cyclotron

8.        A radar display that sweeps outward of the center of the screen while rotating is known as.

1. CRT
2. A scope
3. PPI
4. Periscope

9.        A radar using multiple antennas to shape the beamwidth and automatically adjust directivity is known as

1. Phased array
2. Continous wave
3. Coplanar
4. Pulser

10.     The pulse duration of a radar signal is 600 nsec. The PRF is 185 pulses per second. The duty cycle is

1. 0.01%
2. 5.5%
3. 3.1%
4. 0.1%

11.     Doppler Effect allows which characteristic of a radar target to be measured?

1. Distance
2. Speed
3. Size
4. Altitude

12.     Most radar antennas use

1. Dipole
2. Broadside array
3. Parabolic reflector
4. Discone

13.     The most common radar display is

1. A-scope
2. PPI
3. B scan
4. C scan  

14.     The time it takes to travel one nautical miles is

1. 10.72 microsecond
2. 12.4 microsecond
3. 6.2 microsecond
4. None of these

15.     With a PRR of 800 and a 1 microsec pulse width, if the average power is 80 watts, the duty cycle of the radar transmitter is

1. 0.0008
2. 0.008
3. 0.8
4. 8

16.     If the peak transmitted power in a radar system is system is increased by a factor of 16, the maximum range will be increased by a factor of

1. 2
2. 4
3. 8
4. 16

17.     If the target cross section is changing, the best system for accurate radar tracking is

1. Lobe switching
2. Conical scanning
3. Monopulse
4. Sequential lobing

18.     The biggest disadvantage of CW radar is that it does not give

1. Target velocity
2. Target range
3. Target position
4. None of these

19.     A radar, A scope displays

1. Target position but not range
2. Both target position and range
3. Target range but not position
4. Neither target range nor position

20.     After a radar target has been acquired, the best system for tracking is

1. Nodding
2. Spiral
3. Conical
4. Helical

21.     A radar transmitter has a PRR of 900 pps, each pulse having a duration of 2 microsec and a peak power of 15 kilowatts. The average power and duty cycle are

1. 27 watts and 0.18%
2. 15 watts and 0.018
3. 20 watts and 0.0018%
4. None of these

22.      The determination of position by keeping account of the distance and direction

1. Surface piloting
2. Dead reckoning
3. Celestial navigation
4. None of these

23.     Refers to echoes transmitted by stationary objects

1. Ghosts
2. Jitter
3. Clutter
4. Squitter

24.     A radar mile is equal to_____ yards

1. 2000
2. 3000
3. 1000
4. 4000

25.     If the antenna diameter in a radar system is increased by a factor of 4, the maximum range will be increased by a factor of

1. Square root of 2
2. 2
3. 4
4. 8

26.     An area directly above a radio range station where practically no signal is heard.

1. Radio range
2. Cone of silence
3. Coverage area
4. RDF area

27.     A shipboard equipment which measures the distance between the ship’s bottom and the ocean floor by sending ultrasonic pulses via a transducer which are reflected at the sea bottom and received with the same transducer.

1. Echosounder
2. SONAR
3. Compandor
4. Hydrophone

28.     A navigation system from which hyperbolic lines of position are determined by measuring the difference in the times of arrival of pulses from widely spaced, synchronized transmitting station

1. LORAN
2. TACAN
3. DME
4. VOR

29.     Radio range stations in LFR operate on frequencies between

1. 20 kHz and 40 kHz
2. 200 kHz and 400 khz
3. 30 kHz and 300 kHz
4. 2 MHz and 4 MHz

30.     What is the science of determining the geographic position of a ship, aircraft or guided missile and charting a course for guiding the craft one place to another?

1. Aeronautics
2. Navigation
3. Guessing
4. Direction finding

31.     It is a point on the earth’s surface that can be recognized as part of an accepted set of coordinates such as latitude and longitude

1. Direction
2. Position
3. Landmark
4. Range

32.     When two bearing cross on a chart, what is it called?

1. Direction
2. Position
3. Intersection
4. Fix

33.     The Greenwich Mean Time is also known as

1. IDT
2. Z Time
3. Polar time
4. Solar time

34.     Which of the following divides the earth into two hemispheres, northern and southern?

1. Prime meridian
2. Latitude
3. Longtitude
4. Equator

35.     Which of the following methods of determining a fix involves the use of buoys and beacons?

1. Triangulation
2. Navigation
3. Homing
4. Fixing

36.     What type of map, centered on a location, shows the shortest path to all points on the earth?

1. Topographical map
2. Political map
3. Geographical map
4. Great circle map

37.     A radio navigational aid used to determine the direction of an approaching radio wave.

1. Magnetic compass
2. NDB
3. Compass rose
4. RDF

38.     A moving target 180 degrees from the nose of the ship is

1. On port quarter
2. Dead astern
3. On starboard bow
4. Dead ahead

39.     An aircraft has a magnetic heading of 150 degrees and a relative bearing to a NDB station of 75 degrees. Determine the magnetic bearing of the station in degrees.

1. 150 degrees
2. 75 degrees
3. 230 degrees
4. 225 degrees

40.     The ability of a radar to determine the bearing of a target depends upon the

1. Antenna directivity
2. Speed of light
3. Speed of the target
4. Frequency of the signal

41.     What is the ability of a radar receiver system to discriminate between two or more closely spaced targets on the same range?

1. Range resolution
2. Azimuth
3. Bearing resolution
4. Transponder

42.     What is the ability of a radar receiver system to discriminate between two or more closely spaced

1. Range resolution
2. Azimuth
3. Bearing resolution
4. Transponder

43.     One nautical mile is approximately equal to how many statute miles?

1. 1.61
2. 1.83
3. 1.15
4. 1.47

44.     A low power radar set has a peak pulse power of 3000w and a pulse duration of 2 microsec. If the PRR is 8kHz, what must be the average power

1. 48 w
2. 0.75 Mw
3. 20.8 Mw
4. 1.5 w

45.     Which of the following information cannot be derived from a PPI?

1. Range
2. Speed
3. Azimuth
4. None of these

46.     What is the intermediate frequency for most radar receivers?

1. 30 MHz
2. 30 kHz
3. 600 kHz
4. 600 GHz

47.     In what distance units are marine radars calibrated?

1. Radar mile
2. Statute mile
3. Nautical mile
4. mile

48.     What is a target display on a CRT called?

1. Pulse
2. Blip
3. Burst
4. Beacon

49.     Why must a radar antenna be pointed directly at a target?

1. For high directivity
2. Due tp narrow beamwidth
3. For good scanning
4. Due to the nature of electromagnetic waves

50.     What radar circuit determines the pulse repetition rate?

1. Discriminator
2. Timer
3. Artificial transmission line
4. Pulse rate circuit

51.     Which of the following is not a distress frequency?

1. 2182 kHz
2. 500 kHz
3. 156.8 MHz
4. 1 kHz

52.     The term used for the mechanism of a radar searching for an object.

1. Scanning
2. Tracing
3. Relaying
4. Nodding

53.     ICAO means

1. International Communication Aviation Organization
2. International Civil Administrative Org
3. International Communication thru Authoritative Org
4. International Civil Aviation Organization

54.     What radio navigational aid determines the distance from a transponder beacon by measuring the length of the time the radio signal took to travel to the receiver?

1. Radar
2. LORAN
3. DME
4. Distance marking

55.     VOR stations operate in the ____  band.

1. LF
2. MF
3. UHF
4. VHF

56.     The ILS glide path measures what deviation of n aircraft?

1. Horizontal
2. Vertical
3. Ground speed
4. Distance between aircrafts

57.     A transponder that replies to the interrogating aircraft signal and identifies itself.

1. VOR
2. Radar beacon
3. ILS
4. Localizer

58.     If the aircraft is flying off path in the lower area of the glide slope pattern which modulation signal is prevailing or has the higher strength?

1. 90 Hz
2. 150 Hz
3. 75 MHz
4. 75 Hz

59.     If the aircraft s flying off-course in the left area of the lcalizer pattern, which modulation signal is prevailing or has the higher strength?

1. 90 Hz
2. 150 Hz
3. 75 Mhz
4. 75 Hz

60.     What is the visual marker indication when an aircraft flies through an Outer Marker Beacon?

1. White light
2. Blue light
3. Black light
4. Amber light

61.     A device which limits the display of radar in formation primarily to moving targets

1. DME
2. MTI
3. A scan
4. PPI

62.     Which band in radio spectrum does the radio navigational system DECCA transmit?

a.     LF

b.     VLF

c.     VHF

d.     HF

63.     OMEGA navigation system operates in what frequency band?

1. VLF
2. LF
3. HF
4. VHF

64.     The body that controls and maintains facilities of civil aviation in the Philippines.

1. LTO
2. ATO
3. MARINA
4. MULAWIN

65.     Which of the following signals has the highest priority?

1. Distress
2. Urgency
3. Safety
4. Security

66.     The word “roger” is used by an operator to signify that

1. I have received, understood all of your last transmission
2. Your last message received, understood and will be complied with
3. My transmission is ended and I expect a response from you
4. The transmission is ended and no response is expected

67.     It is the movement of the aircraft about its vertical axis.

a.        Roll

b.        Pitch

c.        Yaw

d.        Crawl

68.     If the target cross section is changing, the best system for accurate tracking is

a.        Nodding

b.        Spiral

c.        Conical

d.       Monopulse

69.     when a single antenna is intended to be used for transmitting and receiving, it is necessary to use a

a.        duplexer

b.        diplexer

c.        combiner

d.        translator

70.     TACAN is a navigational aid providing

a.        Speed and height indication

b.        Bearing and weather information

c.        Bearing and distance indication

d.        Cone of confussion