Question
How can a geomagnetic storm affect HF propagation?
Answer Options
- A) Improve high-latitude HF propagation
- B) Degrade ground wave propagation
- C) Improve ground wave propagation
- D) Degrade high-latitude HF propagation
Correct Answer: D
Explanation
A geomagnetic storm introduces highly charged particles into the Earth’s atmosphere, particularly near the polar regions where the geomagnetic field channels them. This massive influx of particles causes significant disruption and instability in the ionosphere, especially at high latitudes (auroral zones).
The resulting disturbed and turbulent ionosphere causes radio waves to be heavily absorbed and scattered, leading to a degradation or complete blackout of HF communications, particularly on high-latitude paths. While it can occasionally create auroras that reflect VHF signals, the typical effect on HF is degradation.
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