| 1. | The beam-width and the directivity of an antenna are ? | |
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Directly proportional
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Inversely proportional
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Independent of each other
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Equal
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Report Question| 2. | Earth coverage dish antenna is used in satellite system. It is characterized by the fact that ? | |
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It is a narrow beam antenna
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It is parabolic antenna
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It is sharply focused within a small area of the surface of the earth
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It is a wide angle antenna which covers a large area of the surface of the earth
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| 3. | For an antenna to be frequency-independent, it expand or counteract in proportion to the ? | |
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Gain
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Directivity
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Wavelength
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impedance
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| 4. | ………… antenna is most frequently used as reference antenna ? | |
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Parabolic
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Yogi-Uda
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None
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Horn
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| 5. | Antenna gain is ? | |
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Directive gain/Antenna efficiency
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Equal to directive again
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Product of directivity gain and antenna efficiency
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Antenna efficiency/directive gain
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| 6. | Spectral density expresses ? | |
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Average voltage
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Average current
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None of these
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Average power in a waveform as a function of frequency
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| 7. | A Cassegrain reflector antenna has a sub-reflector whose geometrical shape is ? | |
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Ellipsoid
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Paraboloid
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Spherical
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Hyperboloid
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| 8. | The radiation resistance of a thin line centre fed antenna with sinusoid current distribution is ? | |
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73
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73+j42.5
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50
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75
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| 9. | In an axial mode operation of a helical antenna, maximum field radiated by the antenna is ? | |
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Along the axis of the helical antenna
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In both axial and normal planes
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In a plane normal to the helix axis
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None of the above
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| 10. | In an airport, a receiving antenna has a maximum dimension of 3 meters and operates at 100 MHz, An aircraft approaching the airport is 1/2 Km away from the antenna. The aircraft in the …………… region of the antenna. ? | |
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Near-field
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Far-field
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Out of reach
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Close-field
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