General · G3
RADIO WAVE PROPAGATION
Propagation in real depth: sunspot cycles, the MUF, gray-line propagation, and why the same HF band can be dead at noon and wide open after dark.
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37 questions across 3 groups
Group G3A
- G3A01How does a higher sunspot number affect HF propagation?
- G3A02What effect does a sudden ionospheric disturbance have on the daytime ionospheric propagation?
- G3A03Approximately how long does it take the increased ultraviolet and X-ray radiation from a solar flare to affect radio propagation on Earth?
- G3A04Which of the following are the least reliable bands for long-distance communications during periods of low solar activity?
- G3A05What is the solar flux index?
- G3A06What is a geomagnetic storm?
- G3A07At what point in the solar cycle does the 20-meter band usually support worldwide propagation during daylight hours?
- G3A08How can a geomagnetic storm affect HF propagation?
- G3A09How can high geomagnetic activity benefit radio communications?
- G3A10What causes HF propagation conditions to vary periodically in a 26- to 28-day cycle?
- G3A11How long does it take a coronal mass ejection to affect radio propagation on Earth?
- G3A12What does the K-index measure?
- G3A13What does the A-index measure?
- G3A14How is long distance radio communication usually affected by the charged particles that reach Earth from solar coronal holes?
Group G3B
- G3B01What is a characteristic of skywave signals arriving at your location by both short-path and long-path propagation?
- G3B02What factors affect the MUF?
- G3B03Which frequency will have the least attenuation for long-distance skip propagation?
- G3B04Which of the following is a way to determine current propagation on a desired band from your station?
- G3B05How does the ionosphere affect radio waves with frequencies below the MUF and above the LUF?
- G3B06What usually happens to radio waves with frequencies below the LUF?
- G3B07What does LUF stand for?
- G3B08What does MUF stand for?
- G3B09What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the F2 region?
- G3B10What is the approximate maximum distance along the Earth’s surface normally covered in one hop using the E region?
- G3B11What happens to HF propagation when the LUF exceeds the MUF?
- G3B12Which of the following is typical of the lower HF frequencies during the summer?
Group G3C
- G3C01Which ionospheric region is closest to the surface of Earth?
- G3C02What is meant by the term “critical frequency” at a given incidence angle?
- G3C03Why is skip propagation via the F2 region longer than that via the other ionospheric regions?
- G3C04What does the term “critical angle” mean, as applied to radio wave propagation?
- G3C05Why is long-distance communication on the 40-, 60-, 80-, and 160-meter bands more difficult during the day?
- G3C06What is a characteristic of HF scatter?
- G3C07What makes HF scatter signals often sound distorted?
- G3C08Why are HF scatter signals in the skip zone usually weak?
- G3C09What type of propagation allows signals to be heard in the transmitting station’s skip zone?
- G3C10What is near vertical incidence skywave (NVIS) propagation?
- G3C11Which ionospheric region is the most absorbent of signals below 10 MHz during daylight hours?