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22 Cards in this Set
- Front
- Back
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Radar uses what form of energy to detect ships, planes, and land masses?
1. Sound waves 2. Visible light 3. Infrared radiation 4. Electromagnetic energy |
Electromagnetic energy
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What radar measurement of an object is referenced to true north?
1. Height 2. Surface angle 3. Vertical angle 4. One-way distance |
Surface angle
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The elevation angle to the target is the angle between which of the following
references? 1. Ship's heading and line of sight 2. Vertical plane and line of sight 3. Horizontal plane and line of sight 4. Vertical plane and horizontal plane |
Vertical plane and line of sight
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Electromagnetic energy travels through
air at approximately what speed? 1. 984 feet per microsecond 2. 186,000 statute miles per second 3. 162,000 nautical miles per second 4. Each of the above is correct |
Each of the above is
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For an object that is detected 15 miles
from a radar set, what is the approximate time required for the rf energy to travel to and return from the object? 1. 7 microseconds 2. 185 microseconds 3. 271 microseconds 4. 927 microseconds |
927 microseconds
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What is the formula for calculating the time for energy to travel 1 nautical mile?
1. 6080/984 ft per second 2. 2,027 yards/328 yards per micro second 3. none of these 4. Both 1 and 2 |
Both 1 and 2
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The minimum range of a radar depends on the length of time of the transmitter pulse (pulse width) and recovery time. During this period, the radar can NOT receive energy. A radar set with a pulse
width of 5 microseconds and a recovery time of 0. 2 microseconds has a minimum range of approximately 1. 614 yards 2. 787 yards 3. 852 yards 4. 4,100 yards |
852 yards
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Which of the following is a RADAR or RADAR nautical mile?
1. 13.5 Micro seconds 2. 12.35 Micro seconds 3. 12.36 Micro seconds 4. 13.56 Micro seconds |
12.36 Micro seconds
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The range in nautical miles to an object, can be found by which of the following
1. Elapsed time/12.36Ms 2. Elapsed time/12.35Ms 3. Elapsed time/12.38Ms 4. Elapsed time/12.34Ms |
Elapsed time/12.36Ms
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Which of the following is the formula for determining the minimum range?
1. PW+recovery time/2X328 yards 2. PW+recovery time+164 yards 3. None of these 4. Both 1 and 2 |
Both 1 and 2
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Of the following radar characteristics, which has NO effect on maximum range
capability? 1. Recovery time 2. Carrier frequency 3. Receiver sensitivity 4. Pulse-repetition frequency |
Recovery time
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The carrier frequency is often a limiting factor in the maximum range capability of a RADAR system because RF energy above________Mhz is rapidly attenuated by the atmosphere.
1. 2,500 2. 1,675 3. 3,000 4. 2,900 |
3,000
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Which of the following characteristics of
a radar system determines the degree to which the radiated energy is affected by atmospheric conditions? 1. Pulse peak power 2. Carrier frequency 3. Receiver sensitivity 4. Pulse-repetition frequency |
Carrier frequency
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Pulse-repetition time is described as the
1. reciprocal of pulse width 2. period of time from the beginning to the end of a transmitter pulse 3. period of time required for the pulse to travel to the target and return 4. period of time from the beginning of one transmitter pulse to the beginning of the next |
period of time from the beginning of one transmitter pulse to the beginning of the next
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Which of the following terms describes radar returns that exceed the prt of the radar?
1. Clutter 2. Ambiguous 3. Reciprocal 4. Acquisition |
Ambiguous
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What type of transmitter power is measured over a period of time?
1. Peak 2. Return 3. Average 4. Reciprocal |
Average
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What is the formula for maximum unambiguous range for a radar system?
1. 162,000 per second/2XPRT 2. 160,000 per second/2XPRF 3. 165,000 per second/2XPRT 4. 168,000 per second/2XPRF |
162,000 per second/2XPRT
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Which of the following formulas can be
used to compute the duty cycle of a radar set? 1. PWxPRF 2. PW/PRF 3. PW+PRF 4. PW-PRF |
PWxPRF
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What is the formula for Pavg?
1. Pr X Ppk/2 2. Ppk X PRF + PW 3. Ppk X PW X PRF 4. All are correct |
Ppk X PW X PRF
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What is the formula for Ppk?
1. Pavg X PRF X Duty Cycle 2. Pavg/Duty Cycle 3. Prf X PW/Dity Cycle 4. PRF X PW X Duty Cycle |
Pavg/Duty Cycle
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What is the maximum radar horizon distance for a radar set with an antenna 100 feet above the surface of the earth?
1. 8 miles 2. 12.5 miles 3. 80 miles 4. 125 miles |
12.5 miles (given that horizon distance = 1.25 X the square root of the antenna height. in this case 100 ft.
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The relative bearing of a radar echo is measured with respect to which of the
following reference points? 1. True north 2. Magnetic north 3. Centerline of your own ship 4. The position of the antenna |
The position of the antenna
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