78. Circularly polarized antenna is
A. Yagi
B. shombic
C. helical
D. log periodic

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79. In an end fire array, maximum radiation occurs
A. long the array
B. perpendicular to the array
C. at 30? to the array
D. at 45? to the array

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80. Marconi antenna
A. is a wideband antenna
B. is an omnidiretional antenna
C. has corner spacing of X/2
D. has driven elements only

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81. A square corner reflector is used in
A. radio astronomy
B. point-to-point communication
C. TV broadcast
D. all the above

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82. An underground ground antenna near the
A. acts a single antenna of twice the hight
B. acts as a reflector
C. must be horizontally polarized
D. acts as an antenna array.

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83. The effective electrical length of an antenna is
A. equal to its physical length
B. greater than its physical length
C. half its physical length
D. 1/X times its physical length

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84. Grounded antenna is used for frequencies of
A. upto about 1.6 MHz
B. 1.0 MHz to 3 MHz
C. 3 MHz to 30 MHz
D. above 30 MI-lz

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