57. can make the antenna electrically longer.
A. Vertical polarization
B. Capacitive top loading
C. Series capacitor
D. All of the above
58. The bandwidth of an antenna is
A. directly proportional to Q2
B. directly proportional to Q
C. inversely proportional to Q
D. inversely proportional to 1/Q3
59. With reference to ?Triatics' which of the following statements is correct?
A. These are supports for antenna conductors
B. These are the towers or masts which are not used as radiators
C. These are small height antennas directly mounted on jeeps, ships etc.
D. none of these
60. An antenna coupler is used due to all of the following reasons except to
A. discriminate against harmonics
B. provide the output amplifier with correct load impedance
C. prevent reradiation of the local oscillator
D. make the antenna look resistive
61. The gain of an isotropic antenna is
A. 2 db
B. 5 db
C. 10 db
D. 15 db
62. antenna is the standard reference antenna for the directiveness.
D. Half-wave dipole
63. An earthmat is used with antennas due to all the following reasons except
A. improvement of the radiation patternof the antenna
B. provision of an earth for the antenna
C. protection of personnel working underneath
D. impossibility of good ground connection
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