JNTU ONLINE EXAMINATIONS [Mid 2 - awp]

1. The length of subsequent directors of yagi - uda antenna reduces progressively by [01D01]
   1. 2.5 %
   2. 13 %
   3. 10 %
   4. 15 %
2. The distance between reflector & driven element in yagi - uda antenna is [01M01]
   1. 
   2. 
   3. 
   4. 
3. Spacing between director and direcor of yagi uda antenna is [01M02]
   1. 
   2. 
   3. 
   4. 
4. The length of reflector of yagi - uda antenna is [01S01]
   1. 0.48 λ
   2. 0.28 λ
   3. 0.18 λ
   4. 0.3λ
5. The driven element in yagi-uda antenna is [01S02]
   1. folded dipole
   2. reflector
   3. lens
   4. horn
6. The length of driven element of yagi -uda antenna in meters is [01S03]
   1. 
   2. 
   3. 
   4. 
7. The length of reflector of yagi -uda antenna in meters is [01S04]
   1. 
   2. 
   3. 
   4. 
8. The length of first director of yagi -uda antenna in meters is [01S05]
   1. 
   2. 
   3. 
   4. 
9. Spacing between reflector and driven element of yagi Uda antenna is [01S06]
   1. 
   2. 
   3. 
   4. 
10. Spacing between director and driven element of yagi uda antenna is [01S07]
    1. 
    2. 
    3. 
    4. 
11. _ _ _ _ _ _ _ polarization results in more signal strength [02D01]
    1. horizontal
    2. vertical
    3. left circular
    4. right circular
12. The diameter of elements in yagi Uda antenna is [02M01]
    1. 1 to 1.2 cm
    2. 2 to 10 cm
    3. 3 to 5 cm
    4. 10 to 20 cm
13. Less reflection & reduced ghost images possible with _ _ _ _ polarized yagi uda [02M02]
    1. horizontal
    2. vertical
    3. left circular
    4. right circular
14. The adverse effect of closer radiators in yagi uda array is [02S01]
    1. lowering of input impedance of array
    2. increasing of input impedance of array
    3. lowering of output impedance of array
    4. constant input impedance of array
15. For maximum pickup, the receiving yagi uda antenna is mounted [02S02]
    1. horizontally
    2. vertically
    3. 30⁰ inclined
    4. 60⁰ inclined
16. A hollow conductor in yagi uda antenna is preferred because of [02S03]
    1. skin effect
    2. miller effect
    3. fermat effect
    4. debye effect
17. In fringe area installation, _ _ _ _ _ _ _ used along with yagi uda antenna to improve reception [02S04]
    1. booster amplifier
    2. buck amplifier
    3. all pass filter
    4. operation amplifier
18. The gain of yagi uda six element antenna for operation at 500 MHz is [02S05]
    1. 11dBi
    2. 20dBi
    3. 100dBi
    4. 5dBi
19. The length of reflector element of yagi uda six element antenna for operation at 500 MHz is [02S06]
    1. 28.8 cm
    2. 40 cm
    3. 100 cm
    4. 10 .8cm
20. For 5 element yogi Uda (UHF & VHF TV channels) reflector length L_R is [02S07]
    1. 0.15 λ
    2. λ
    3. 0.1λ
    4. 2λ
21. The field pattern in the horizontal plane for corner reflector at a distance r from antenna is [03M01]
    1. 
    2. 
    3. 
    4. 
22. If the feed to vertex distance d is made equal to side length L in reflector then the aperture width is [03M02]
    1. 1.414 L
    2. 2L
    3. 1.6L
    4. 1.334L
23. A corner reflector without an exciting antenna can be used as [03S01]
    1. passive reflector
    2. active reflector
    3. lens
    4. dipole
24. The corner angle for passive reflector is [03S02]
    1. 90⁰
    2. 50⁰
    3. 10⁰
    4. 80⁰
25. In grid type of reflector the spacing between conductors is [03S03]
    1. 
    2. 
    3. 
    4. 
26. The height of conductors( for /2 driven element antenna) in grid type of reflector is [03S04]
    1. 
    2. 
    3. 
    4. 
27. Compared to isolated /2 antenna, corner reflector antenna power gain will be _ _ _ _ times higher [03S05]
    1. 10 to 20
    2. 30 to 50
    3. 20 to 60
    4. 40 to 50
28. One of the following uses corner reflector antenna [03S06]
    1. point to point communication
    2. television
    3. radio astronomy
    4. internet
29. If corner angle is 90⁰ then range of corner to dipole spacing is [03S07]
    1. 
    2. 
    3. 
    4. 
30. The relative field pattern E in the plane of the driven λ /2 element of a square corner reflector is [04D01]
    1. 
    2. 
    3. 
    4. 
31. The normalized field pattern E( Ø ) for paraboloid with uniformly illuminated aperture is given by [04D02]
    1. 
    2. 
    3. 
    4. 
32. A square corner reflector has a spacing of λ /4 between the driven /2 element and the corner. The directivity is [04M01]
    1. 12.8 dBi
    2. 15.8 dBi
    3. 121.8 dBi
    4. 19.8 dBi
33. If corner angle is 180⁰ then range of corner to dipole spacing is [04S01]
    1. 
    2. 
    3. 
    4. 
34. A square corner reflector has a driven λ/2 element. The distance between the driven element and corner is λ /2 . The terminal impedance of driven element is [04S02]
    1. 125 ohm
    2. 150 ohm
    3. 100 ohm
    4. 200 ohm
35. A square corner reflector has a driven /2 element. The distance between the driven element and corner is /2 . The half power beam width in θ is [04S03]
    1. 60⁰
    2. 90⁰
    3. 45⁰
    4. 120⁰
36. A square corner reflector has a driven λ /2 element. The distance between the driven element and corner is λ /2 . The half power beam width in Ø is [04S04]
    1. 42⁰
    2. 50⁰
    3. 45⁰
    4. 30⁰
37. A square corner reflector has a driven λ/ 2 element. The distance between the driven element and corner is λ /2 Directivity from impedance of driven & image dipoles is ` [04S05]
    1. 11.9 dBi
    2. 20.9 dBi
    3. 30.9 dBi
    4. 3 dBi
38. A square corner reflector has a driven λ /2 element. The distance between the driven element and corner is λ /2 Directivity from HPBWs is [04S06]
    1. 11.4 dBi
    2. 20.4 dBi
    3. 13.4 dBi
    4. 15.3 dBi
39. For large circular apertures, the beam width between first nulls is [04S07]
    1. 
    2. 
    3. 
    4. 
40. The directivity D of a large uniformly illuminated circular aperture is [05D01]
    1. 
    2. 
    3. 
    4. 
41. The field intensity ratio in the aperture plane for parabolic reflector is [05M01]
    1. 
    2. 
    3. 
    4. 1
42. The beam width between half power points for a large circular aperture is [05S01]
    1. 
    2. 
    3. 
    4. 
43. The F/D for parabolic reflector is [05S02]
    1. 0.25 to 0.5
    2. 0.5 to 5
    3. 5 to 10
    4. 4 to 8
44. The distance from any point P on a parabolic curve to a fixed point F is called [05S03]
    1. focus
    2. vertex
    3. feed point
    4. cassegrain
45. A parabolic reflector have a [05S04]
    1. directional feed
    2. offset feed
    3. vertex feed
    4. isotropic feed
46. To make the field completely uniform across the aperture would require a feed pattern with [05S05]
    1. inverse taper
    2. exponential taper
    3. uniform taper
    4. non uniform taper
47. The loss in aperture due to feed antenna blockage avoided by using [05S06]
    1. offset feed
    2. directional feed
    3. Horn feed
    4. Dipolefeed
48. The flared out wave guide is also known as [05S07]
    1. Horn antenna
    2. Yagi-uda antenna
    3. dipole
    4. paraboloid
49. For optimum horn antenna, optimum length ,L is [06D01]
    1. 
    2. 
    3. 
    4. 
50. If δ = 0.2 , length L = 62.5 , then the pyramidal horn antenna flare angle in E- plane is [06D02]
    1. 9.1⁰
    2. 1⁰
    3. 5⁰
    4. 6⁰
51. For pyramidal horn directivity,D is [06M01]
    1. 
    2. 
    3. 
    4. 
52. Beam width between first nulls for optimum E-plane rectangular Horn is [06M02]
    1. 
    2. 
    3. 
    4. 
53. If a and b are mouth dimensions in Z & Y directions L is horn length from mouth to apex then `a` is [06S01]
    1. 
    2. 
    3. 
    4. 
54. For optimum Horn antenna , optimum δ is [06S02]
    1. 
    2. 
    3. 
    4. 
55. If = 0.2 and E plane aperture a_E = 10 λ , then length L for pyramidal horn is [06S03]
    1. 
    2. 
    3. 
    4. 
56. If E-plane aperture of pyramidal antenna is aE = 10 λ , then HPBW(E-plane) [06S04]
    1. 5.6⁰
    2. 2⁰
    3. 10⁰
    4. 8⁰
57. If H plane aperture of pyramidal antenna is a_H = 13.7 λ , then HPBW(H-plane) [06S05]
    1. 4.9⁰
    2. 10⁰
    3. 6⁰
    4. 2⁰
58. Beam width between first nulls for optimum H- plane rectangular horn is [06S06]
    1. 
    2. 
    3. 
    4. 
59. For pyramidal horn antenna, if h is height in E -plane & w is width in H-plane, the power gain G_p is [07D01]
    1. 
    2. 
    3. 
    4. 
60. If Δ A is elemental area , E is magnitude of radiated field generated by Δ A , d is the distance to Δ A , θ is angle with respect to an axis that is perpendicular to mouth of parabolic antenna then strength of electric field at Δ A is [07D02]
    1. 
    2. 
    3. 
    4. 
61. Beam width between half power points for optimum H-plane rectangular horn is [07M01]
    1. 
    2. 
    3. 
    4. 
62. Typical value of δ for H-plane horn antenna is [07M02]
    1. 0.4
    2. 0.3
    3. 0.1
    4. 1
63. If a and b are mouth dimensions in Z & Y directions L is horn length from mouth to apex. then half power beam widths in degrees in H plane is [07M03]
    1. 
    2. 
    3. 
    4. 
64. Beam width between half power points for optimum E-plane rectangular horn is [07S01]
    1. 
    2. 
    3. 
    4. 
65. If a and b are mouth dimensions in Z & Y directions L is horn length from mouth to apex. Then `b` is [07S02]
    1. 0.81 a
    2. 0.98a
    3. 2a
    4. 0.5a
66. If a and b are mouth dimensions in Z & Y directions L is horn length from mouth to apex .then gain is [07S03]
    1. 
    2. 
    3. 
    4. 
67. If a and b are mouth dimensions in Z & Y directions, L is horn length from mouth to apex. then half power beam widths in degrees in E plane is [07S04]
    1. 
    2. 
    3. 
    4. 
68. the field across the mouth of horn antenna is [07S05]
    1. section of spherical wave front
    2. elliptical wave front
    3. triangular wave front
    4. rectangular wave front
69. According to fermat`s principle, R/λ ₀ is equal to [08D01]
    1. 
    2. 
    3. 
    4. 
70. Delay type lens antennas regarded basically as [08D02]
    1. end fire antennas with poly rod
    2. broadside antennas with poly rod
    3. end fire antennas with dipole
    4. broadside antennas with dipole
71. Many element yagi uda antenna is a [08M01]
    1. rudimentary lens
    2. dielectric lens
    3. director
    4. poly rod
72. One of the following material is used for constructing dielectric lens [08M02]
    1. Lucite
    2. Paraffin
    3. Teflon
    4. Wax
73. If the flare angles of horn are too large the field across the mouth considered to be [08S01]
    1. not equi phase field
    2. equi phase field
    3. rectangular field
    4. triangular field
74. One of the following applied to delay lenses antennas [08S02]
    1. electrical path length is increased by lens medium
    2. electrical path length is decreased exponentially by lens medium
    3. electrical path length is unaltered by lens medium
    4. electrical path length is decreased linearly by lens medium
75. One of the following applied to fast lenses antennas [08S03]
    1. electrical path length is increased exponentially by lens medium
    2. electrical path length is decreased by lens medium
    3. electrical path length is unaltered by lens medium
    4. electrical path length is increased linearly by lens medium
76. One of the following is a delay type lens antenna [08S04]
    1. Dielectric lens
    2. E plane metal plate lens
    3. EH metal plate
    4. Horn
77. One of the following is a delay type lens antenna [08S05]
    1. H plane metal lens
    2. E plane metal plate lens
    3. EH metal plate
    4. Horn
78. One of the following material is used for constructing dielectric lens [08S06]
    1. Polystyrene
    2. Paraffin
    3. Teflon
    4. Wax
79. For a cylindrical lens field ratio is [09D01]
    1. 
    2. 
    3. 
    4. 
80. The thickness Z of a zone step in zoned lens is [09M01]
    1. 
    2. 
    3. 
    4. 
81. For non magnetic materials, index of refraction n is [09M02]
    1. 
    2. 
    3. 
    4. 
82. One of the following is valid according to Fermat's principle [09S01]
    1. all paths from source to plane surface are of equal electrical lengths
    2. all paths from source to plane surface are of unequal electrical lengths
    3. all paths from source to load surface are of equal electrical lengths
    4. some paths from source to plane surface are of equal electrical lengths
83. _ _ _ _ _ _ _ illumination of aperture suppresses minor lobes in lens antennas [09S02]
    1. taper
    2. Uniform
    3. random
    4. zero
84. To avoid resonance effect in artificial dielectric lens antennas the size of metal particles should be [09S03]
    1. small compared to design wave length
    2. 10 times larger compared to design wave length
    3. 20 times larger compared to design wave length
    4. equal to design wave length
85. The maximum particle dimension( parallel to electric field) in artificial dielectric lens antennas is [09S04]
    1. less than /4
    2. equal to
    3. greater than /2
    4. 2
86. To avoid diffraction effects the spacing between the particle in artificial dielectric lens antennas is [09S05]
    1. less than
    2. equal to
    3. greater than
    4. 20
87. Polarization of artificial dielectric in lens antenna is [09S06]
    1. Nql
    2. nq/l
    3. nq/l²
    4. Nl/q
88. The effective relative permittivity of an artificial dielectric of conductive spheres in _r is [09S07]
    1. 1+4 prod Na³
    2. 1-4 prod Na³
    3. 1+4 prod Na⁴
    4. 1-4 prod Na²
89. The effective index of refraction of an artificial dielectric of conducting spheres is [10D01]
    1. 
    2. 
    3. 
    4. 
90. The equation for the contour of the zoned lens is [10D02]
    1. 
    2. 
    3. 
    4. 
91. The effective dielectric constant of artificial dielectric medium in lens antenna is [10M01]
    1. 
    2. 
    3. 
    4. 
92. The effective relative permeability of an artificial dielectric of conducting spheres is [10M02]
    1. 
    2. 
    3. 
    4. 
93. The disadvantage of E plane metal plate lens is [10S01]
    1. frequency sensitive
    2. frequency independent
    3. phase sensitive
    4. phase independent
94. The disadvantage of H plane metal plate lens is [10S02]
    1. unsymmetrical aperture illumination in E plane
    2. symmetrical aperture illumination in E plane
    3. unsymmetrical aperture illumination in H plane
    4. symmetrical aperture illumination in H plane
95. According to MUELLER & TYRRELL, the directivity of poly rod antenna is [10S03]
    1. 
    2. 
    3. 
    4. 
96. According to MUELLER & TYRRELL, the HPBW of poly rod antenna is [10S04]
    1. 
    2. 
    3. 
    4. 
97. A properly designed lens produces [10S05]
    1. a plane wave front
    2. spherical wave front
    3. elliptical wave front
    4. non uniform plane wave front
98. The conducting strips in lens antenna are [10S06]
    1. parallel to electrical field
    2. perpendicular to electrical field
    3. inclined to electrical field
    4. perpendicular to magnetic field
99. The efficiency of power transfer between a generator and load is [11D01]
    1. 
    2. 
    3. 
    4. 
100. According to FRIIS transmission formula, power received is [11D02]
     1. 
     2. 
     3. 
     4. 
101. The refractive index of LUNEBURG lens is [11M01]
     1. 
     2. 
     3. 
     4. 
102. The gain of antenna under test (AUT) is [11M02]
     1. 
     2. 
     3. 
     4. 
103. With radar technique gain of antenna under test (AUT) is [11M03]
     1. 
     2. 
     3. 
     4. 
104. Total gain of antenna under test (AUT) interms of gain of AUT at horizontal polarization G_H & vertical polarization G_v is [11S01]
     1. 
     2. 
     3. 
     4. 
105. The focusing action of lens antenna is [11S02]
     1. sensitive to frequency
     2. independent of frequency
     3. insensitive to phase
     4. insensitive to frequency and phase
106. The phase velocity in lens antenna depends on [11S03]
     1. frequency
     2. phase
     3. delay
     4. square of frequency
107. In antenna parameter measurements distance between primary and secondary antenna should be [11S04]
     1. 
     2. 
     3. 
     4. 
108. If r is distance between primary (transmitter) and secondary (receiver) antenna , then r is [11S05]
     1. 
     2. 
     3. 
     4. 
109. As per rayleigh criterion the roughness is defined as [12D01]
     1. 
     2. 
     3. 
     4. 
110. The attenuation function F is [12M01]
     1. 
     2. 
     3. 
     4. 
111. If the surface is rough , roughness R is [12M02]
     1. >10
     2. 2 to 4
     3. 5 to9
     4. 0
112. For accurate field pattern the primary antenna should produce [12S01]
     1. a plane wave of uniform amplitude & phase over a distance r
     2. a plane wave of uniform amplitude & phase over a distance r²
     3. a plane wave of non uniform amplitude & phase over a distance r
     4. a plane wave of uniform amplitude over a distance r
113. Directivity is defined as ratio of [12S02]
     1. maximum radiation intensity to average radiation intensity
     2. minimum radiation intensity to average radiation intensity
     3. average radiation intensity to maximum radiation intensity
     4. average radiation intensity to minimum radiation intensity
114. One of the following method is used in computation of directivity [12S03]
     1. Orange slice
     2. FEM
     3. Trapezoidal
     4. MM
115. One of the following method is used in computation of directivity [12S04]
     1. Conical cut
     2. FEM
     3. Trapezoidal
     4. MM
116. Waves that arrive at receiver after reflection or scattering in the ionosphere are known as [12S05]
     1. sky waves
     2. surface waves
     3. ground waves
     4. troposperic waves
117. Ground wave signal divided as [12S06]
     1. space and surface wave
     2. space and sky wave
     3. surface and sky wave
     4. reflected and refracted wave
118. Space wave is made up of [12S07]
     1. direct wave
     2. reflected wave
     3. refracted wave
     4. diffracted wave
119. Reflection factor for horizontal polarization, R_his [13D01]
     1. 
     2. 
     3. 
     4. 
120. Electric field for space wave is [13M01]
     1. 
     2. 
     3. 
     4. 
121. For smooth surface roughness R is [13S01]
     1. <>
     2. > 20
     3. 10
     4. 5
122. When the incident wave is near grazing over a smooth earth the reflection coefficient is [13S02]
     1. -1.0
     2. -2
     3. 1
     4. 10
123. The attenuation function dependent on [13S03]
     1. distance , frequency, constants of earth
     2. distance & radiation
     3. constants of earth & delay
     4. phase, constants of earth & radiation
124. For un attenuated surface wave, the attenuation function is [13S04]
     1. 1
     2. 10
     3. 5
     4. 2
125. At Ψ=0, un attenuated surface attenuation function ( at low frequency and good ground conductivity) value is [13S05]
     1. 2
     2. 10
     3. 5
     4. 0
126. At Ψ =0 , surface of earth ground wave attenuation factor A is [13S06]
     1. 
     2. F-10
     3. F²
     4. 0
127. For surface wave numerical distance depends on [13S07]
     1. frequency, ground constants, actual distance to transmitter
     2. frequency, ground constants
     3. phase, frequency, ground constants
     4. ground constants, actual distance to transmitter
128. The phase constant `b` is a measure of [13S08]
     1. power factor angle of earth
     2. ground constant
     3. numerical distance
     4. attenuation factor
129. For vertical dipole antenna over a plane earth , electric field is [14D01]
     1. 
     2. 
     3. 
     4. 
130. Space wave field of a horizontal dipole in the plane perpendicular to axis of dipole is [14D02]
     1. 
     2. 
     3. 
     4. 
131. Real part of conductivity of ionized gas is [14M01]
     1. 
     2. 
     3. 
     4. 
132. For a wave propagating in a dielectric medium of permittivity, & incident upon a second medium of , the reflection coefficient of horizontally polarized wave, R_h is [14M02]
     1. 
     2. 
     3. 
     4. 
133. If earth constant and frequency are such that ,then earth will be [14S01]
     1. resistive[100 ohms]
     2. reactive
     3. conductive
     4. resistive(1000 ohms)
134. The numerical distance interms of phase constant b and for surface wave is [14S02]
     1. 
     2. 
     3. 
     4. 
135. If earth constant and frequency are such that x > > in _r then power factor angle is [14S03]
     1. 0
     2. 10
     3. 2
     4. 5
136. If earth constant and frequency are such that x > > in _r ,then earth will be [14S04]
     1. resistive
     2. inductive
     3. conductive
     4. capacitive
137. Approximate value of collision frequency in Ionosphere is [14S05]
     1. 
     2. 
     3. 
     4. 
138. E region extends from [14S06]
     1. 90 - 130 km
     2. 20 - 30 km
     3. 40 - 50 km
     4. 1 - 10 km
139. In the plane parallel to axis of dipole the space wave field is [15D01]
     1. 
     2. 
     3. 
     4. 
140. The ratio of horizontal to vertical field will be [15D02]
     1. 
     2. 
     3. 
     4. 
141. Reflection factor for vertical polorization R_v is [15D03]
     1. 
     2. 
     3. 
     4. 
142. The horizontal component of electric field of surface wave E_h is [15M01]
     1. 
     2. 
     3. 
     4. 
143. For VHF propagation between elevated antennas, one of the following is considered [15S01]
     1. surface wave neglected
     2. surface wave considered
     3. sky wave neglected
     4. space wave neglected
144. For VHF propagation between elevated antennas, one of the following is considered [15S02]
     1. Ψ is very small
     2. Ψ =100
     3. Ψ =90
     4. Ψ =50
145. For VHF propagation between elevated antennas, one of the following is considered [15S03]
     1. 
     2. 
     3. 
     4. 
146. A vertically polarized wave at the surface of earth will have [15S04]
     1. forward tilt
     2. backward tilt of 10
     3. no tilt
     4. backward tilt of 20
147. The vertical component of electric field of surface wave E_v is [15S05]
     1. 
     2. 
     3. 
     4. 
148. The magnitude of surface wave tilt depends on [15S06]
     1. conductivity & permittivity of earth
     2. reactivity of earth
     3. permeability of earth
     4. permeability & permittivity of earth
149. For a wave propagating in a dielectric medium of permittivity, & incident upon a second medium of , the reflection coefficient of vertically polarized wave, R_V is [16D01]
     1. 
     2. 
     3. 
     4. 
150. The refractivity of atmosphere, N is [16M01]
     1. (77.6 / T) P +( 4810 e / T)
     2. (77.6 / T) +( 4810 e / T)
     3. P +( 4810 e / T)
     4. (77.6 / T) P +( 4810 e )
151. Radius of curvature ρ of earth is [16M02]
     1. 
     2. 
     3. 
     4. 
152. The curvature of the earth affects the propagation of [16S01]
     1. ground wave signal
     2. sky wave signal
     3. surface wave signal
     4. duct signal
153. The divergence factor D for (spherical earth) ground reflected wave is [16S02]
     1. <>
     2. 2
     3. > 10
     4. 5
154. If the ground reflected wave is reflected from spherical earth, its energy is [16S03]
     1. more diverged
     2. less diverged
     3. unaffected
     4. more converged
155. Curves that show the variation of modified index of refraction with height is known as [16S04]
     1. M curves
     2. N curves
     3. H curves
     4. E curves
156. Standard propagation occurs when the modified index of refraction increases [16S05]
     1. linearly with height
     2. exponentially with height
     3. linearly with distance
     4. uniformly with height
157. If the slope of M curve decreases near the surface of earth, _ _ _ _ _ _ _ propagation results [16S06]
     1. sub standard
     2. super standard
     3. standard
     4. non standard
158. If the slope of M curve increases near the surface of earth, _ _ _ _ _ _ propagation results [16S07]
     1. super standard
     2. sub standard
     3. standard
     4. non standard
159. Tropospheric forward scatter can provide reliable beyond the horizon signal for distances upto [17D01]
     1. 300 or 400 miles
     2. 100 or 200 miles
     3. 500 or 1000 miles
     4. 10 to 50 miles
160. If the lower side of the duct is at surface of earth, it is known as a [17M01]
     1. surface duct
     2. space duct
     3. sky duct
     4. tropospheric
161. Elevated ducts found at elevations of [17M02]
     1. 1000 to 5000 ft
     2. 20 to 10,0 ft
     3. 500 to 1000 ft
     4. 8000 to 15000 ft
162. In folded dipole, two identical conductors in parallel serve as [17S01]
     1. transformer
     2. generator
     3. load
     4. source
163. When a reflector such as a copper screen is placed closed to a half wave antenna, the resultant radiation pattern is [17S02]
     1. uni directional
     2. conical
     3. bi directional
     4. triangular
164. If the modified index decreases with height over a portion of the range of height, the rays will be curved downward and this condition known as [17S03]
     1. duct propagation
     2. sky propagation
     3. space propagation
     4. tropospheric propagation
165. When the inverted portion of M curve is elevated above the surface of the earth, the lower side of the duct is also elevated, and the duct is called an [17S04]
     1. elevated duct
     2. surface duct
     3. space duct
     4. sky duct
166. Elevated ducts are due to a subsidence of [17S05]
     1. large air masses
     2. ionosphere
     3. troposphere
     4. water vapor
167. Over land areas, surface ducts are produced by [17S06]
     1. radiation cooling of the earth
     2. water vapor
     3. heating of earth
     4. large air masses
168. Trapping more likely occurs at [17S07]
     1. UHF
     2. VHF
     3. VLF
     4. HF
169. Narrow band signals due to tropospheric forward scatter propagation have been Received up to [18D01]
     1. 600 miles
     2. 700 miles
     3. 1000 miles
     4. 800 miles
170. Plasma frequency ω _p is given by [18M01]
     1. 
     2. 
     3. 
     4. 
171. Approximate value of collision frequency in Ionosphere is [18M02]
     1. 
     2. 
     3. 
     4. 
172. During day time, F layer splits into [18S01]
     1. 
     2. E & D
     3. C & D
     4. C & E
173. The electron density in Ionosphere will be [18S02]
     1. 10⁴ electrons/cc
     2. 10 electrons /cc
     3. 10² electrons/cc
     4. 1000 electrons /cc
174. C region extends from [18S03]
     1. 50 - 70 km
     2. 20 - 30 km
     3. 40 - 50 km
     4. 1 - 10 km
175. D region extends from [18S04]
     1. 70 - 90 km
     2. 60 - 70 km
     3. 40 - 60 km
     4. 5 - 10 km
176. Other layers with in E region that do not have a permanent existence are called [18S05]
     1. sporadic E layers
     2. sporadic F₁ layers
     3. sporadic F₂ layers
     4. sporadic D layers
177. _ _ _ _ _ _ _ represents the combined effects of collisions in all species of particles present. [18S06]
     1. collision frequency
     2. angular frequency
     3. plasma frequency
     4. spatial frequency
178. The variation in collision frequency V with height depends on [18S07]
     1. gas pressure, electron thermal velocity & ion density
     2. gas pressure, collision frequency
     3. gas pressure, electron thermal velocity & plasma frequency
     4. gas pressure, electron thermal velocity & earth constant
179. The maximum ionization density ,N for any layer is [19D01]
     1. 
     2. 
     3. 
     4. 
180. Maximum usable frequency is [19M01]
     1. 
     2. 
     3. 
     4. 
181. For E layer, critical frequency, f_E is [19M02]
     1. 
     2. 
     3. 
     4. 
182. The refractive index of Ionosphere, n is [19S01]
     1. 
     2. 
     3. 
     4. 
183. Sudden ionospheric disturbance known as [19S02]
     1. dellinger effect
     2. meissner effect
     3. skin effect
     4. miller effect
184. Shown in Figure(a) represents Figure(a) [19S03]
     1. Surface duct
     2. Elevated duct
     3. Sky duct
     4. Standard atmosphere
185. Dellinger effect produces [19S04]
     1. complete radio fade out
     2. partial radio fade out
     3. complete radio reception
     4. improved radio signal reception
186. In ionospheric storms, the radio wave propagation becomes [19S05]
     1. very erratic
     2. very much reliable
     3. slightly degraded
     4. reliable
187. If the ionosphere is turbulent and loses its normal stratification, then this type of irregularity is known as [19S06]
     1. ionospheric storm
     2. sporadic ionosphere
     3. non deviative ionospheric absorption
     4. deviative ionospheric absorption
188. Shown in Figure(a) Figure(a) [19S07]
     1. standard atmosphare
     2. surface duct
     3. elevated duct
     4. sky duct
189. The attenuation factor for ionosphereic propagation α is [20D01]
     1. 
     2. 
     3. 
     4. 
190. real part of Effective permittivity of ionized gas is [20D02]
     1. 
     2. 
     3. 
     4. 
191. Debye length, λ _D is [20M01]
     1. 
     2. 
     3. 
     4. 
192. Thomson scattering is incoherent at altitudes above [20M02]
     1. 100 km , for f > 200 MHz
     2. 200 km for f > 500 MHz
     3. 300 km for f > 100 KHz
     4. 400 km for f > 100 GHz
193. The irregularity of ionosphere occurring only in polar regions during a period of sunspot maximum is known as [20S01]
     1. polar cap absorption
     2. non deviative polar absorption
     3. deviative polar absorption
     4. sporadic polar absorption
194. The absorption that occurs in D region is known as [20S02]
     1. non deviative absorption
     2. deviative absorption
     3. polar cap absorption
     4. sporadic absorption
195. The absorption that occurs in the region when the wave is bent is called [20S03]
     1. deviative absorption
     2. non deviative absorption
     3. polar cap absorption
     4. sporadic absorption
196. Lowest useful high frequency (LUHF) depends on [20S04]
     1. effective radiated power
     2. meissner effect
     3. earth constants only
     4. polar cap absorption
197. LUHF depends on [20S05]
     1. absorption characteristics of ionospher for paths between transmitter and receiver
     2. meissner effect
     3. earth constants only
     4. polar cap absorption
198. LUHF depends on [20S06]
     1. required field strength & radio noise
     2. meissner effect
     3. earth constants only
     4. polar cap absorption