Topic G9D Quick Review Audio


Which of the following antenna types will be most effective as a Near Vertical Incidence Skywave (NVIS) antenna for short-skip communications on 40 meters during the day?

  1. A horizontal dipole placed between 1/10 and 1/4 wavelength above the ground
  2. A vertical antenna placed between 1/4 and 1/2 wavelength above the ground
  3. A left-hand circularly polarized antenna
  4. A right-hand circularly polarized antenna


What is the feed-point impedance of an end-fed half-wave antenna?

  1. Very low
  2. Approximately 50 ohms
  3. Approximately 300 ohms
  4. Very high


In which direction is the maximum radiation from a portable VHF/UHF "halo" antenna?

  1. Broadside to the plane of the halo
  2. Opposite the feed point
  3. Omnidirectional in the plane of the halo
  4. Toward the halo's supporting mast


What is the primary purpose of antenna traps?

  1. To permit multiband operation
  2. To notch spurious frequencies
  3. To provide balanced feed-point impedance
  4. To prevent out-of-band operation


What is an advantage of vertical stacking of horizontally polarized Yagi antennas?

  1. It allows quick selection of vertical or horizontal polarization
  2. It allows simultaneous vertical and horizontal polarization
  3. It narrows the main lobe in azimuth
  4. It narrows the main lobe in elevation


Which of the following is an advantage of a log periodic antenna?

  1. Wide bandwidth
  2. Higher gain per element than a Yagi antenna
  3. Harmonic suppression
  4. Polarization diversity


Which of the following describes a log periodic antenna?

  1. Element length and spacing vary logarithmically along the boom
  2. Impedance varies periodically as a function of frequency
  3. Gain varies logarithmically as a function of frequency
  4. SWR varies periodically as a function of boom length


How does a "screwdriver" mobile antenna adjust its feed-point impedance?

  1. By varying its body capacitance
  2. By varying the base loading inductance
  3. By extending and retracting the whip
  4. By deploying a capacitance hat


What is the primary use of a Beverage antenna?

  1. Directional receiving for low HF bands
  2. Directional transmitting for low HF bands
  3. Portable direction finding at higher HF frequencies
  4. Portable direction finding at lower HF frequencies


In which direction or directions does an electrically small loop (less than 1/3 wavelength in circumference) have nulls in its radiation pattern?

  1. In the plane of the loop
  2. Broadside to the loop
  3. Broadside and in the plane of the loop
  4. Electrically small loops are omnidirectional


Which of the following is a disadvantage of multiband antennas?

  1. They present low impedance on all design frequencies
  2. They must be used with an antenna tuner
  3. They must be fed with open wire line
  4. They have poor harmonic rejection


What is the common name of a dipole with a single central support?

  1. Inverted V
  2. Inverted L
  3. Sloper
  4. Lazy H


What is the combined vertical and horizontal polarization pattern of a multi-wavelength, horizontal loop antenna?

  1. A figure-eight, similar to a dipole
  2. Four major loops with deep nulls
  3. Virtually omnidirectional with a lower peak vertical radiation angle than a dipole
  4. Radiation maximum is straight up