General Class License Exam Questions
Antennas and Feedlines
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Group G9A Antenna feed lines; characteristic impedance, and attenuation; SWR calculation, measurement and effects; matching networks
G9A01 Which of the following factors determine the characteristic impedance of a parallel conductor antenna feed line?
G9A02 What are the typical characteristic impedances of coaxial cables used for antenna feed lines at amateur stations?
G9A03 What is the characteristic impedance of flat ribbon TV type twinlead?
G9A04 What might cause reflected power at the point where a feed line connects to an antenna?
G9A05 How does the attenuation of coaxial cable change as the frequency of the signal it is carrying increases?
G9A06 In what units is RF feed line loss usually expressed?
G9A07 What must be done to prevent standing waves on an antenna feed line?
G9A08 If the SWR on an antenna feed line is 5 to 1, and a matching network at the transmitter end of the feed line is adjusted to 1 to 1 SWR, what is the resulting SWR on the feed line?
G9A09 What standing wave ratio will result when connecting a 50 ohm feed line to a non-reactive load having 200 ohm impedance?
G9A10 What standing wave ratio will result when connecting a 50 ohm feed line to a non-reactive load having 10 ohm impedance?
G9A11 What standing wave ratio will result when connecting a 50 ohm feed line to a non-reactive load having 50 ohm impedance?
G9A12 What standing wave ratio will result when connecting a 50 ohm feed line to a non-reactive load having 25 ohm impedance?
G9A13 What standing wave ratio will result when connecting a 50 ohm feed line to an antenna that has a purely resistive 300 ohm feed point impedance?
G9A14 What is the interaction between high standing wave ratio (SWR) and transmission line loss?
G9A15 What is the effect of transmission line loss on SWR measured at the input to the line?
Group G9B Basic antennas
G9B01 What is one disadvantage of a directly fed random-wire HF antenna?
G9B02 Which of the following is a common way to adjust the feed point impedance of a quarter wave ground plane vertical antenna to be approximately 50 ohms?
G9B03 What happens to the feed point impedance of a ground plane antenna when its radials are changed from horizontal to sloping downward?
G9B04 What is the radiation pattern of a dipole antenna in free space in the plane of the conductor?
G9B05 How does antenna height affect the horizontal (azimuthal) radiation pattern of a horizontal dipole HF antenna?
G9B06 Where should the radial wires of a ground-mounted vertical antenna system be placed?
G9B07 How does the feed point impedance of a 1/2 wave dipole antenna change as the antenna is lowered below 1/4 wave above ground?
G9B08 How does the feed point impedance of a 1/2 wave dipole change as the feed point is moved from the center toward the ends?
G9B09 Which of the following is an advantage of a horizontally polarized as compared to a vertically polarized HF antenna?
G9B10 What is the approximate length for a 1/2 wave dipole antenna cut for 14.250 MHz?
G9B11 What is the approximate length for a 1/2 wave dipole antenna cut for 3.550 MHz?
G9B12 What is the approximate length for a 1/4 wave vertical antenna cut for 28.5 MHz?
Group G9C Directional antennas
G9C01 Which of the following would increase the bandwidth of a Yagi antenna?
G9C02 What is the approximate length of the driven element of a Yagi antenna?
G9C03 Which statement about a three-element, single-band Yagi antenna is true?
G9C04 Which statement about a three-element, single-band Yagi antenna is true?
G9C05 How does increasing boom length and adding directors affect a Yagi antenna?
G9C06 What configuration of the loops of a two-element quad antenna must be used for the antenna to operate as a beam antenna, assuming one of the elements is used as a reflector?
G9C07 What does "front-to-back ratio" mean in reference to a Yagi antenna?
G9C08 What is meant by the "main lobe" of a directive antenna?
G9C09 How does the gain of two 3-element horizontally polarized Yagi antennas spaced vertically 1/2 wavelength apart typically compare to the gain of a single 3-element Yagi?
G9C10 Which of the following is a Yagi antenna design variable that could be adjusted to optimize forward gain, front-to-back ratio, or SWR bandwidth?
G9C11 What is the purpose of a gamma match used with Yagi antennas?
G9C12 Which of the following is an advantage of using a gamma match for impedance matching of a Yagi antenna to 50 ohm coax feed line?
G9C13 Approximately how long is each side of the driven element of a quad antenna?
G9C14 How does the forward gain of a two-element quad antenna compare to the forward gain of a three-element Yagi antenna?
G9C15 Approximately how long is each side of the reflector element of a quad antenna?
G9C16 How does the gain of a two-element delta-loop beam compare to the gain of a two-element quad antenna?
G9C17 Approximately how long is each leg of a symmetrical delta-loop antenna?
G9C18 What happens when the feed point of a quad antenna of any shape is moved from the midpoint of the top or bottom to the midpoint of either side?
G9C19 How does antenna gain stated in dBi compare to gain stated in dBd for the same antenna?
G9C20 What is meant by the terms dBi and dBd when referring to antenna gain?
Group G9D Specialized antennas
G9D01 What does the term NVIS mean as related to antennas?
G9D02 Which of the following is an advantage of an NVIS antenna?
G9D03 At what height above ground is an NVIS antenna typically installed?
G9D04 What is the primary purpose of antenna traps?
G9D05 What is an advantage of vertical stacking of horizontally polarized Yagi antennas?
G9D06 Which of the following is an advantage of a log periodic antenna?
G9D07 Which of the following describes a log periodic antenna?
G9D08 Why is a Beverage antenna not used for transmitting?
G9D09 Which of the following is an application for a Beverage antenna?
G9D10 Which of the following describes a Beverage antenna?
G9D11 Which of the following is a disadvantage of multiband antennas?