Topic G3A Quick Review Audio


What is the significance of the sunspot number with regard to HF propagation?

  1. Higher sunspot numbers generally indicate a greater probability of good propagation at higher frequencies
  2. Lower sunspot numbers generally indicate greater probability of sporadic E propagation
  3. A zero sunspot number indicates that radio propagation is not possible on any band
  4. A zero sunspot number indicates undisturbed conditions


What effect does a Sudden Ionospheric Disturbance have on the daytime ionospheric propagation of HF radio waves?

  1. It enhances propagation on all HF frequencies
  2. It disrupts signals on lower frequencies more than those on higher frequencies
  3. It disrupts communications via satellite more than direct communications
  4. None, because only areas on the night side of the Earth are affected


Approximately how long does it take the increased ultraviolet and X-ray radiation from solar flares to affect radio propagation on Earth?

  1. 28 days
  2. 1 to 2 hours
  3. 8 minutes
  4. 20 to 40 hours


Which of the following are least reliable for long-distance communications during periods of low solar activity?

  1. 80 meters and 160 meters
  2. 60 meters and 40 meters
  3. 30 meters and 20 meters
  4. 15 meters, 12 meters, and 10 meters


What is the solar flux index?

  1. A measure of the highest frequency that is useful for ionospheric propagation between two points on Earth
  2. A count of sunspots that is adjusted for solar emissions
  3. Another name for the American sunspot number
  4. A measure of solar radiation at 10.7 centimeters wavelength


What is a geomagnetic storm?

  1. A sudden drop in the solar flux index
  2. A thunderstorm that affects radio propagation
  3. Ripples in the ionosphere
  4. A temporary disturbance in Earth's magnetosphere


At what point in the solar cycle does the 20-meter band usually support worldwide propagation during daylight hours?

  1. At the summer solstice
  2. Only at the maximum point of the solar cycle
  3. Only at the minimum point of the solar cycle
  4. At any point in the solar cycle


Which of the following effects can a geomagnetic storm have on radio propagation?

  1. Improved high-latitude HF propagation
  2. Degraded high-latitude HF propagation
  3. Improved ground wave propagation
  4. Degraded ground wave propagation


What benefit can high geomagnetic activity have on radio communications?

  1. Auroras that can reflect VHF signals
  2. Higher signal strength for HF signals passing through the polar regions
  3. Improved HF long path propagation
  4. Reduced long delayed echoes


What causes HF propagation conditions to vary periodically in a roughly 28-day cycle?

  1. Long term oscillations in the upper atmosphere
  2. Cyclic variation in Earth's radiation belts
  3. The sun's rotation on its axis
  4. The position of the moon in its orbit


How long does it take charged particles from coronal mass ejections to affect radio propagation on Earth?

  1. 28 days
  2. 14 days
  3. 4 to 8 minutes
  4. 20 to 40 hours


What does the K-index indicate?

  1. The relative position of sunspots on the surface of the sun
  2. The short-term stability of Earth's magnetic field
  3. The stability of the sun's magnetic field
  4. The solar radio flux at Boulder, Colorado


What does the A-index indicate?

  1. The relative position of sunspots on the surface of the sun
  2. The amount of polarization of the sun's electric field
  3. The long-term stability of Earth's geomagnetic field
  4. The solar radio flux at Boulder, Colorado


How are radio communications usually affected by the charged particles that reach Earth from solar coronal holes?

  1. HF communications are improved
  2. HF communications are disturbed
  3. VHF/UHF ducting is improved
  4. VHF/UHF ducting is disturbed