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83 Cards in this Set
- Front
- Back
The acronym sonar is derived from what
words? 1. Sound, navigation, and radar 2. Sound, navigation, and ranging 3. Sound, naval, and radar 4. Sound, naval, and ranging |
2. Sound, navigation, and ranging
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A sonar transducer can be compared to which
of the following items? 1. Microphone 2. Amplifier 3. Speaker 4. Receiver |
3. Speaker
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Signal strength lost as sound waves travel
through water is known by what term? 1. Saturation 2. Attenuation 3. Radiation loss 4. Transmission loss |
4. Transmission loss
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Which of the following sea states causes the
greatest amount of absorption? 1. Whitecap waves 2. Large swells 3. Small swells 4. Calm |
1. Whitecap waves
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Sound waves in seawater travel how many
times faster than sound waves in air? 1. 8 2. 2 3. 10 4. 4 |
4. 4
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Which of the following sea floor surfaces has
the least amount of signal loss? 1. Rocky 2. Muddy 3. Sandy 4. Smooth and hard |
4. Smooth and hard
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Multiple reflections of a sound wave is referred
to by what term? 1. Resounding 2. Reverberating 3. Scattering 4. Rumbling |
2. Reverberating
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Which of the following statements best describes
the effect of divergence on sound waves? 1. The wave spreads out and becomes weaker with distance 2. The beam converges and becomes stronger with distance 3. The beam divides with distance 4. The beam width remains the same with distance |
1. The wave spreads out and becomes weaker
with distance |
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What is the most important factor affecting the
speed of a sound wave in seawater? 1. Salinity 2. Depth 3. Temperature 4. Frequency |
3. Temperature
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An increase in the salinity of seawater has what
effect on the sound wave? 1. Speed increases 2. Speed decreases 3. Scattering increases 4. Scattering decreases |
1. Speed increases
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According to the Doppler effect, when the
source of a sound wave is moving away from the receiver, what apparent change in the sound wave takes place? 1. The intensity increases 2. The wavelength decreases 3. The frequency decreases 4. The frequency increases |
3. The frequency decreases
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What are the three most common propagation
paths for sound waves? 1. Reflective, refractive, and direct 2. Direct, bottom bounce, and reflective 3. Bottom bounce, surface bounce, and reflective 4. Direct, bottom bounce, and convergence |
4. Direct, bottom bounce, and convergence
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What is the minimum number of sonobuoys
normally deployed during a USW mission? 1. 1 2. 2 3. 3 4. 4 |
3. 3
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Acoustic data received from a sonobuoy is
transmitted to the sonobuoy receiver using (a) what frequency band, and (b) what type of modulation? 1. (a) VHF (b) FM 2. (a) VHF (b) AM 3. (a) UHF (b) FM 4. (a) HF (b) AM |
1. (a) VHF (b) FM
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Sonobuoys that transmit an acoustic pulse and
detect a resulting echo are classified as what type of sonobuoy? 1. Passive 2. Active 3. Ringing 4. Delay |
2. Active
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What are the three methods of deploying a
sonobuoy? 1. Pneumatic, free-fall, and cartridge 2. Pneumatic, free-fall, and hydraulic 3. Free-fall, hydraulic, and piston 4. Cartridge, hydraulic, and piston |
1. Pneumatic, free-fall, and cartridge
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Sonobuoy descent-retarding devices are necessary
for what reason? 1. To prevent ice build-up 2. To allow electronic circuits to activate 3. To reduce water entry shock 4. To allow visual tracking |
3. To reduce water entry shock
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How are sonobuoys activated?
1. Atmospheric pressure switch during descent 2. Saltwater battery activation 3. Command signal from the operator 4. Preset timer |
2. Saltwater battery activation
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What happens to the sonobuoy after the battery
dies? 1. It sinks to the bottom 2. A recovery pinger activates 3. A recovery float deploys 4. It remains in place and decomposes |
1. It sinks to the bottom
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Sonobuoys equipped with an EFS system have
what capability? 1. Unlimited battery life 2. Electromagnetic pulse protection 3. Frequency discrimination 4. Selectable channel, life and depth settings |
4. Selectable channel, life and depth settings
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A LOFAR sonobuoy uses what type of
hydrophone? 1. Unidirectional 2. Omnidirectional 3. Hybrid 4. Reactive |
2. Omnidirectional
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Under most situations, what type of sonobuoy
is best for initial detection? 1. DIFAR 2. LOFAR 3. VLAD 4. DICASS |
2. LOFAR
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What information can a DIFAR sonobuoy
provide that a LOFAR sonobuoy cannot? 1. Submarine bearing 2. Submarine depth 3. Submarine size 4. Water temperature |
1. Submarine bearing
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Which of the following sonobuoys is designed
for long-range submarine detection in deep water? 1. LOFAR 2. DIFAR 3. VLAD 4. DICASS |
3. VLAD
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DICASS sonobuoys operate on the same
principle as what other electronic system? 1. INS 2. IFF 3. TACAN 4. Radar |
4. Radar
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DICASS sonobuoys are commanded to ping by
what source? 1. A UHF signal from the USW aircraft 2. A VHF signal from a surface ship 3. Apreset timer located within the sonobuoy 4. A range proximity switch located within the sonobuoy |
1. A UHF signal from the USW aircraft
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An EER sonobuoy is typically used in conjunction
with what other sonobuoy for long-range detection? 1. DICASS 2. VLAD 3. LOFAR 4. DIFAR |
2. VLAD
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What are the two special-purpose sonobuoys?
1. BT and DIFAR 2. BT and DLC 3. DLC and DIFAR 4. DLC and LOFAR |
2. BT and DLC
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What information does a BT sonobuoy provide?
1. Salinity 2. Pressure versus depth 3. Water temperature at sea surface 4. Water temperature versus depth |
4. Water temperature versus depth
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The ARR-78 sonobuoy receiver is capable of
simultaneous reception of up to what number of sonobuoys? 1. 5 2. 10 3. 20 4. 99 |
3. 20
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The ARR 84 sonobuoy receiver is used in the
SH-60 series helicopter for what reason? 1. Accommodation of weight restrictions 2. Rotor nulling circuitry 3. Higher signal to noise ratio 4. Less sonobuoy monitoring requirements |
1. Accommodation of weight restrictions
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What component of the sonobuoy-based sonar
system extracts acoustic target information from both active and passive sonobuoys? 1. Sonobuoy receiver 2. Power supply 3. Data display 4. Spectrum analyzer |
4. Spectrum analyzer
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The OTPI system works in conjunction with
what other aircraft system? 1. DF 2. VOR 3. TACAN 4. ACLS |
1. DF
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The OTPI system provides what information to
the USW pilot? 1. Distance to the sonobuoy 2. Sonobuoy bearing with respect to true north 3. Sonobuoy bearing with respect to aircraft heading 4. Sonobuoy depth |
3. Sonobuoy bearing with respect to aircraft
heading |
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Dipping sonar systems use what type of sonar
detection? 1. Active only 2. Passive only 3. Active and passive 4. Active and array |
3. Active and passive
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What distinct advantage does a dipping sonar
have over a sonobuoy based system? 1. Low operating cost 2. Operator control of the search depth 3. Longer operating time 4. Search area increased |
2. Operator control of the search depth
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In addition to active and passive sonar modes, a
dipping sonar provides what other information? 1. Water salinity and temperature 2. Water pressure salinity 3. Communications and water temperature 4. Communications and water pressure |
3. Communications and water temperature
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The electrical interface between the sonar set
units mounted in the helicopter and the submerged sonar transducer is provided by what component of the ASQ-13F dipping sonar set? 1. Power supply 2. Multiplexer 3. Dome control 4. Sonar data computer |
2. Multiplexer
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What unit of the ASQ-13F converts sound
energy to electrical signals? 1. Receiver 2. Computer 3. Transceiver 4. Transducer |
4. Transducer
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A submerged sonar transducer is used to
transmit and receive voice signals to and from other USW helicopters, submarines, or similarly equipped surface ships during what ASQ-13F mode of operation? 1. BT 2. UVC 3. Active 4. Passive |
2. UVC
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Angles of change in the Earth’s natural
magnetic field in the east-west direction is known by what term? 1. Dip angle 2. Variation angle 3. Equatorial angle 4. Force angle |
2. Variation angle
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The maximum range at which a submarine
may be detected depends on the intensity of its magnetic anomaly and what other factor? 1. The sensitivity of the detector 2. The size of the submarine 3. The salinity of the seawater 4. The temperature of the seawater |
1. The sensitivity of the detector
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If the detectable strength of a magnetic field
source has a given value at a given distance and the distance is doubled, the detectable strength of the source at the increased distance will then be how much of its former value? 1. One-half 2. One-third 3. One-fourth 4. One-eighth |
1. One-half
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Any noise or disturbance originating in the
aircraft or its equipment that could produce a signal on a MAD equipment recorder is known by what term? 1. Static voltage 2. Magnetic noise 3. Stray voltage 4. Phantom noise |
2. Magnetic noise
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Maneuver noises caused by eddy current flow
can be minimized by taking what action? 1. Making slow aircraft maneuvers 2. Making quick aircraft maneuvers 3. Flying in a circular pattern 4. Flying in a zigzag pattern |
1. Making slow aircraft maneuvers
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Any magnetic field may be defined in terms of
what number of axial coordinates? 1. 1 2. 2 3. 3 4. 4 |
3. 3
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What is the purpose of magnetic compensation
in USW aircraft? 1. To provide a negative polar coefficient 2. To provide a positive polar coefficient 3. To counteract the Earth’s magnetic field 4. To provide a magnetically clean environment |
4. To provide a magnetically clean environment
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Compensation for an aircraft’s dc magnetic
field is accomplished by using how many electromagnetic loops? 1. 1 2. 2 3. 3 4. 4 |
4. 4
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The natural spin axis wobble rate of a
particular atom is referred to by what term? 1. Deviation frequency 2. Larmor frequency 3. Wobble frequency 4. Carver frequency |
2. Larmor frequency
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In the ASQ-81 solid-state MAD detector, the
energy level of the electrons is increased, and the atoms are properly oriented by what procedure? 1. Polar excitation 2. RF induction 3. Electromagnetic pulsing 4. Optical pumping |
4. Optical pumping
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What component or components of a helium
magnetometer detect the energy level changes of the helium atoms and produces an electrical output? 1. Absorption cell 2. Helium lamp 3. Infrared detector 4. Excitation coils |
3. Infrared detector
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What are the main components of a basicMAD
detecting set? 1. Magnetic array, field compensator, and detecting set control 2. Magnetic array, magnetic detector, and detecting set control 3. Magnetic detector, amplifier-power supply, and detecting set control 4. Magnetic detector, magnetic array, and detecting set control |
3. Magnetic detector, amplifier-power supply,
and detecting set control |
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When maintenance is performed on or near the
magnetometer head, what type of tools must be used? 1. Nonferrous 2. Stainless steel 3. Tempered steel 4. Iron |
1. Nonferrous
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What is the approximate warm-up time for the
AN/ASQ-81 MAD system? 1. 3 min 2. 5 min 3. 7 min 4. 10 min |
2. 5 min
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What fault indicator on the MAD control box
indicates an amplifier failure? 1. 1 2. 2 3. 3 4. 4 |
2. 2
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What is the purpose of magnetic compensation?
1. To increase the intensity of the anomaly 2. To match the magnetic field of the aircraft with the anomaly 3. To eliminate the magnetic field 4. To reduce the effects of unwanted magnetic disturbances |
4. To reduce the effects of unwanted magnetic
disturbances |
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What are the three magnetic fields relative to
MAD compensation? 1. Transverse, longitudinal, and vertical 2. Transverse, radial, and polar 3. Radial, longitudinal, and horizontal 4. Horizontal, longitudinal, and vertical |
1. Transverse, longitudinal, and vertical
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In practice, how many terms are needed to
compensate any aircraft satisfactorily? 1. 16 2. 12 3. 9 4. 3 |
3. 9
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The compensator group adapter (CGA) serves
what purpose? 1. Allows manual compensation 2. Provides a maintenance interface 3. Allows modules to be interchanged 4. Computerizes the compensation calculation |
4. Computerizes the compensation calculation
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What is the purpose of the submarine anomaly
detector (SAD) system? 1. Separates submarine anomalies from magnetic noise 2. Replaces the MAD system 3. Automatically identifies friendly submarines 4. Calculates submarine depth |
1. Separates submarine anomalies from magnetic
noise |
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What are the two main factors that affect the
velocity of sound in seawater? |
The temperature and salinity of the water.
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A sound wave traveling from an area of warm
water into an area of cold water will be affected in what way? |
It will bend toward the area of cold water.
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Sonobuoys that transmit an acoustic pulse
and detect a resulting echo are classified as what type of sonobuoy? |
Active sonobuoys.
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Sonobuoys equipped with an EFS system
have what capability? |
The capability of selecting channel, life and depth settings.
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What information can a DIFAR sonobuoy
provide that a LOFAR sonobuoy cannot? |
Submarine bearing.
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Which of the following sonobuoys provides
water temperature data? |
BT sonobuoys.
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The OTPI system provides what information
to the USW pilot? |
Sonobuoy bearing information with respect to aircraft heading.
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What type of naval aircraft employs the
AN/ASQ-13F dipping sonar system? |
The SH-60F.
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On a dipping sonar system, what component
generates and transmits sound energy into the water? |
The transducer.
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The angle between an imaginary line tangent
to the Earth’s surface and to the magnetic line of force where it enters the Earth’s surface is known by what term? |
Dip angle.
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The gamma, the measure of magnetic intensity,
is symbolized by what Greek letter? |
The Greek letter ã.
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Magnetic noise sources fall into what two
major categories? |
Dc circuit noise and maneuver noise.
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The compensation of MAD equipment for
magnetic noise is usually performed at what location? |
In flight at sea.
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When electrons are excited to an energy level
that is higher in energy and longer lasting in duration, this energy state is known as what type of energy state? |
Metastable energy state.
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The Larmor frequency of electrons varies
with magnetic field intensity at the rate of how many Hz per ã? |
28.
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What component of a helium magnetometer
detects the energy level changes of the helium atoms and produces an electrical output? |
The infrared detector.
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How many helium absorption cell/IR detector
pairs are contained in the detector element? |
Six (6) absorption cell/IR detector pairs.
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The signals between the magnetic detector
and the amplifier-power supply are transmitted through what type of cable? |
A single coaxial cable.
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The fault indicator on the detecting set
control labeled 3 indicates a failure in what component? |
The magnetic detector.
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Magnetic field terms that are designated by
two capital letters, such as TT, are what type of terms? |
Induced terms.
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The ECA of the AN/ASA-65 sends compensation
currents to what component? |
The ECA provides compensation currents to the MAD boom compensation coils.
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The CGA performs what function?
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The CGA calculates compensation data.
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What are the functions of the ASA-64/ASA-71
SAD system? |
The ASA-64/ASA-71 SAD system separates submarine anomalies from magnetic
noise and provides visual and audio indications that a submarine contact has been made. |