85. Tropospheric scatteris used with frequencies in the following range :
A. HF
B. VHF
C. UHF
D. UF

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86. If the power of a transmitter is doubled, the field strength at a point will go up by ____ dB.
A.2
B.6
C.3
D.4

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87. Propagation in VHF band is by ____ waves.
A. ground
B. space
C. sky
D. Air

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88.  The adsorption of radio waves by the ionosphere depends mainly on
A. their frequency
B. their distance from the transmitter
C. the polarization of the waves
D. the strenth of waves

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89. First TV station in India was established in
A.1956
B.1959
C.1962
D.1965

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90. The standard aspect ratio of a television raster is
A. 2 : 1
B. 3 : 2
C. 3 : 4
D. 5 : 3

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91. In television, 4: 3 represents the
A. interlace ratio
B. maximum horizontal deflection
C. aspect ratio
D. ratio of the two diagonals

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