Module 10

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bugsbunny2255
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193713
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Module 10
Updated:
2013-01-30 14:20:28
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AT2 adv
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WTF
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  1. Radio energy is transmitted through
    which of the following mediums?
    Space
  2. Energy is transmitted from a transmitter
    into space using which of the following
    devices?
    A transmitting antenna
  3. Transmitted rf energy takes what form as
    it is sent into space?
    An electromagnetic field
  4. The dimensions of a transmitting antenna
    are determined by which of the following
    factors?
    Transmitted frequency
  5. A device used to radiate or receive
    electromagnetic wave energy is referred
    to as a/an
    antenna
  6. An antenna that can be mounted to
    radiate rf energy either vertically or
    horizontally is classified as which of the
    following types?
    Hertz
  7. A complete antenna system consists of
    which of the following components?
    • A feeder line, a coupling device, and
    • an antenna
  8. What component in an antenna system
    transfers energy from the transmitter to
    the antenna?
    A feeder
  9. The type, size, and shape of an antenna
    are determined by which of the following
    factors?
    Power output of the transmitter, Transmitter frequency, and direction to the receiver.
  10. Moving electric and magnetic fields in
    space have what (a) phase and
    (b) angular relationships?
    In Phase and Perpendicular
  11. What is the length of each half of the
    wire for a dipole antenna?
    1/4 wavelength
  12. On a dipole antenna, the sinusoidal
    variation in charge magnitude lags the
    sinusoidal variation in current by what
    amount?
    1/4 cycle
  13. On a standing wave, the points of high
    current and voltage are identified by
    which of the following terms?
    Loops
  14. The presence of standing waves indicates
    which of the following conditions of an
    antenna?
    Resonance
  15. The antenna property that allows the
    same antenna to both transmit and
    receive energy is
    reciprocity
  16. There is a ratio between the amount of
    energy propagated in certain directions
    by a directional antenna compared to the
    energy that would be propagated in these
    directions if the antenna were not
    directional. This ratio is known as which
    of the following antenna characteristics?
    Gain
  17. The polarization plane of the radiation
    field is determined by which of the
    following fields?
    Electric field only
  18. For best reception of a signal from a
    horizontally polarized antenna, the
    receiving antenna should be mounted so
    that it has what relationship with the
    transmitting antenna?
    90 degrees
  19. An electric field that rotates as it travels
    through space exhibits what type of
    polarization?
    Elliptical
  20. For ground-wave transmissions, what
    type of polarization is required?
    Vertical
  21. For high-frequency operation, which of
    the following antenna polarization
    patterns is preferred?
    Horizontally polarized
  22. Omnidirectional transmission is obtained
    from which of the following antennas?
    Vertical half-wave
  23. With an antenna height of 40 feet and a
    transmitter frequency of 90 megahertz,
    which of the following antenna radiation
    patterns is best for transmitting over
    bodies of water?
    Vertically polarized
  24. To select a desired signal and
    discriminate against interfering signals
    from strong vhf and uhf broadcast
    transmissions, which of the following
    actions should you take?
    • Use a vertically polarized receiving
    • antenna
  25. A vertically mounted transmission line is
    LEAST affected by which of the
    following antenna radiation patterns?
    Horizontally polarized
  26. An antenna with which of the following
    radiation resistance values will exhibit
    reduced efficiency?
    39 ohms
  27. An isotropic radiator radiates energy in
    which of the following patterns?
    Omnidirectional
  28. An ordinary flashlight is an example of
    what type of radiator?
    Anisotropic
  29. The area enclosed by the radiation
    pattern is the
    lobe
  30. Inserting an inductor or capacitor in
    series with an antenna is one method of
    electrically changing the electrical length
    of an antenna. What is this method
    called?
    Loading
  31. Many complex antennas are constructed
    from what basic antenna?
    The half-wave antenna
  32. On an energized half-wave antenna,
    which of the following electrical
    conditions exist?
    Voltage is maximum at the ends
  33. Which of the following radiation patterns
    is/are exhibited by a simple vertical
    doublet antenna?
    Nondirectional in the horizontal plane. And the directional in the vertical plane.
  34. A method of feeding energy to a halfwave
    antenna is to connect one end
    through a capacitor to the output stage.
    What is this method of feeding called?
    End feed and voltage feed.
  35. An antenna supplied by the center-feed
    method is fed at what point?
    Low voltage and high current.
  36. The basic Marconi antenna has which of
    the following characteristics?
    • One-quarter wavelength and
    • grounded at one end
  37. The Marconi antenna behaves as a dipole
    for which of the following reasons?
    • An image antenna is formed by
    • reflections from the ground
  38. A series of conductors arranged in a
    radial pattern and buried in the ground
    beneath the antenna is referred to as a
    ground screen
  39. A folded dipole can be used instead of a
    simple, center-fed dipole for which of the
    following purposes?
    Matching impedance
  40. An antenna arrangement that has
    elements aligned in a straight line is
    referred to as what type array?
    Unidirectional
  41. To select a desired signal and
    discriminate against interfering signals,
    the receiving antenna should have which
    of the following characteristics?
    Be vertically polarized
  42. Adding more elements to a collinear
    antenna array produces which of the
    following effects?
    Increased gain
  43. What is the maximum number of
    elements ordinarily used in a collinear
    array?
    Four
  44. Constructing a collinear array with
    elements longer than 1/2 wavelength has
    which of the following effects on antenna
    characteristics?
    Increased frequency range
  45. In a two-element collinear array,
    maximum gain is obtained when the
    center-to-center spacing between the
    ends of the elements is approximately
    what electrical distance?
    0.75 wavelength
  46. Compared with collinear arrays,
    broadside arrays have which of the
    following advantages?
    Sharper tuning
  47. Optimum gain is obtained from a
    broadside array when the spacing of its
    elements is which of the following
    distances?
    One-half wavelength
  48. An end-fire array physically resembles
    the collinear array except that it is more
    compact. What disadvantage does the
    endfire array possess?
    It has low radiation resistance
  49. What is the range of electrical spacing
    between the elements of an end-fire
    array?
    1/8 to 1/4 wavelength
  50. Assuming that the elements are correctly
    spaced, the directivity of an end-fire
    array may be increased by which of the
    following actions?
    Increasing the number of elements
  51. A unidirectional pattern can be obtained
    from an end-fire array by using what
    phase relationship between the energy
    fed to adjacent elements?
    90º
  52. The ratio of energy radiated by an array
    in the principal direction of radiation to
    the energy radiated in the opposite
    direction describes which of the
    following relationships?
    Front-to-back ratio
  53. The Yagi antenna is an example of what
    type of antenna array?
    Multielement parasitic
  54. The addition of parasitic elements to the
    Yagi antenna has which of the following
    effects on antenna characteristics?
    Increased gain, Narrower beam width, and narrower frequency response.
  55. An antenna which is designed especially
    for vertically-polarized ground waves at
    low frequencies is the
    Beverage antenna
  56. What is the phase relationship of the
    signals that feed the V antenna?
    180º
  57. A rhombic antenna is essentially a
    combination of which of the following
    antennas?
    Two collinear arrays in parallel
  58. A rhombic antenna has which of the
    following advantages?
    Simple construction, wide frequency range, and noncreitical adjustment.
  59. The principal disadvantage of the
    rhombic antenna is its
    large antenna site
  60. The unidirectional radiation pattern of
    the rhombic antenna is caused by which
    of the following antenna characteristics?
    Termination resistance
  61. Horizontal half-wave antennas mounted
    at right angles to each other in the same
    horizontal plane make up which of the
    following antennas?
    Turnstile
  62. The most common means of obtaining a
    low-radiation angle from a vertical
    quarter-wave antenna is by what
    procedure?
    Adding a ground plane
  63. A corner reflector antenna is used for
    which of the following purposes?
    To produce a unidirectional pattern
  64. If a corner-reflector antenna is
    horizontally polarized, its radiation
    pattern will take on what shape?
    A narrow beam in the vertical plane
  65. When radio or radar antennas are
    energized by transmitters, you must not
    go aloft until which of the following
    requirements are met?
    • A working aloft "chit" has been filled
    • out and signed by proper authority
  66. A transmission line is designed to perform which of the following functions?
    Guide electrical energy from point to point
  67. All transmission lines must have two ends,the input end and the output end. What other name is given to the input end?
    Generator end
  68. A measurement of the voltage to current ratio (Ein/I in) at the input end of a transmission line is called the
    input impedance
  69. Which of the following lines is NOT a transmission medium?
    Load line
  70. Electrical power lines are most often made of which of the following types of transmission lines?
    Two-wire open line
  71. Uniform capacitance throughout the length of the line is an advantage of which of the following transmission lines?
    Shielded pair
  72. What is the primary advantage of a rigid coaxial line?
    Low radiation losses
  73. Which of the following wave-guides is seldom used because of its large energy loss characteristics?
    Dielectric
  74. To some degree, transmission lines always exhibit which of the following types of losses?
    I2R
  75. Skin effect is classified as which of the following types of loss?
    Copper
  76. What transmission-line loss is caused by magnetic lines of force not returning to the conductor?
    Radiation
  77. The conductance value of a transmission line represents which of the following values?
    Expected value of current flow through the insulation
  78. Electrical constants in a transmission line are distributed in which of the following ways?
    Along the length of the line
  79. Leakage current in a two-wire transmission line is the current that flows through what component?
    The insulator
  80. Conductance is the reciprocal of what electrical property?
    Resistance
  81. A transmission line that has current flowing through it has which, if any, of the following fields about it?
    Both electric and magnetic fields
  82. Maximum transfer of energy from the source to the transmission line takes place when what impedance relationship exists between the source and the transmission line?
    When the load impedance equals source impedance
  83. The characteristic impedance (Z0) of a transmission line is calculated by using which of the following ratios?
    E to I at every point along the line
  84. For a given voltage, what determines the amount of current that will flow in a transmission line?
    Characteristic impedance
  85. When should lumped values for transmission-line constants be used to calculate characteristic impedance?
    When the line is short compared to one wavelength
  86. In actual practice, the characteristic impedance of a transmission line is usually within which of the following resistance ranges?
    50 to 600 ohms
  87. The input impedance of a transmission line is affected by which of the following properties?
    Radiation loss, Series inductance, and parallel capacitance
  88. When a dc voltage is applied to a transmission line and the load absorbs all the energy, what is the resulting relationship between current and voltage?
    They are evenly distributed along the line
  89. The initial waves that travel from the source to the load of a transmission line are referred to as what type of waves?
    Incident
  90. Waves that travel from the output end to the input end of a transmission line are referred to as what type of waves?
    Reflected
  91. The instantaneous voltage on an infinite transmission line can be plotted against time by using which of the following instruments?
    An oscilloscope
  92. On an infinite transmission line with an ac voltage applied, which of the following is an accurate description of the effective voltage distribution along the line?
    Voltage is constant at all points
  93. The velocity of propagation on a transmission line is controlled by which of the following line characteristics?
    Capacitance and inductance
  94. The total charge on a transmission line is equal to the current multiplied by which of the following factors?
    Time
  95. With only capacitance and inductance of the line given, the time (T) required for a voltage change to travel down a transmission line can be found by what formula? The characteristic impedance for an infinite transmission line can be figured using which of the following ratios?
    T - L/C 1/2
  96. The characteristic impedance for an infinite transmission line can be figured using which of the following ratios?
    Input voltage to input current
  97. When a transmission line is not terminated in its characteristic impedance (Z0), what happens to the incident energy that is NOT transferred to the load?
    It is returned along the transmission line
  98. In an open-ended transmission line with an ac signal applied, what is the phase relationship between the incident and reflected voltage waves?
    180 degrees out of phase
  99. The resultant of the incident and reflected voltage waves is called the standing wave.Its value is figured by using which of the following procedures?
    Algebraically adding the instantaneous values of the two waveforms
  100. At the end of an open-ended transmission line, which, if any, of the following voltage waves is at its maximum value?
    Incident
  101. On a transmission line that is carrying an ac signal, what is the relative value of the resultant voltage wave 1/4 wavelength from the open end?
    Zero
  102. Which of the following conditions exist at the end of a shorted transmission line?
    Minimum voltage and maximum current
  103. Transmission line is considered to be nonresonant (flat) when it is terminated in which of the following ways?
    In an impedance equal to Z0
  104. Of the following terms, which one is used for the nonresonant transmission line?
    An untuned line
  105. A transmission line that is resonant is sometimes referred to as which of the following types of lines?
    Tuned
  106. A short-circuited section of transmission line that is an odd number of quarter wavelengths long shows the same characteristics as which of the following devices?
    A parallel-resonant circuit
  107. Which of the following sections of transmission line can be used as a parallel resonant circuit?
    A shorted 1/4-wavelength section
  108. A generator connected to an open-ended line greater than 1/4 wave-length but less than 1/2 wave-length senses which of the following circuit component characteristics?
    Inductive reactance
  109. Which of the following conditions of current (I) and impedance (Z) exist at even quarter-wave points on a shorted transmission line?
    High I, low Z
  110. What is the maximum distance, in wavelengths (), between adjacent zero current points on an open-circuited line?
    1  wavelenth
  111. When a line is terminated in a capacitance,the capacitor performs which, if any, of the following circuit actions?
    It reflects all the energy
  112. When a transmission line is terminated in an inductive reactance, which, if any, of the following phase shifts takes place with respect to the current and voltage?
    Both voltage and current are phase-shifted
  113. When a transmission line is terminated in a resistance greater than Z0, which of the following conditions exist?
    The end of the line appears as an open circuit
  114. On a transmission line, reflections begin at which of the following locations?
    At the load
  115. The ratio of maximum voltage to minimum voltage on a transmission line is referred to as the
    vswr
  116. Which of the following ratios samples the magnetic field along a line?
    Iswr

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