78. Sea clutter returns occur
A. due to reflections from rain clouds
B. at short ranges
C. due to land reflections
D. none of the above

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79. A short pulse transmission on short ranges
A. provides good minimum range
B. provides good bearing resolution
C. provides goods range resolution
D. both (a) & (c)

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80. If the 1.5 nm range is selected by the operator, the long-pulse/short pulse control line from the display unit will select a PRT of and a pulse length of
A. 1500 Hz, 0.55 us
B. 750 Hz, 0.08 ilS
C. 1500 Hz, 0.08 is
D. 750 Hz, 0.55 us

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81. A given lossless antenna produces a beam that is 100 in azimuth and 20? in elevation. The power gain of this antenna would be
A. 648/n
B. 324/7c
C. n/50
D.200

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82.  A radar operating at 3 GHz and using a 1 m diameter parabolic reflector antenna with an efficiency factor of (1/7t) would radiate with a power gain of
A.3140
B.314
C.3.14
D.10

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83. A beam --idth of 10 in the azimuth direction and 1? in elevation direction implies a radiated beam solid angle (in steradians) of about
A.1
B.0.1
C. 1/3240
D. n/180

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84. With reference to accuracy of range measurement, if the received signal to noise ratio is increased by a factor of 4, the root mean square value of the range error would
A. increase by a factor of 2
B. reduce by a factor of 4
C. increase by a factor of 4
D. reduce by a factor of 2

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