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AhaBulb: Stuff Everyone Should Know · ahabulb.com/ham-ionosphere-reflects-hf

Which region of the atmosphere can reflect HF radio waves?

The ionosphere.

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  1. The troposphere
  2. The ionosphere ✔
  3. The stratosphere

Why: The ionosphere is a layer high in the atmosphere charged by the sun. It bends HF signals back to Earth, letting them travel very long distances.

Huh, didn't know that: Long-distance ionospheric propagation is far more common on HF than on VHF.

The dad joke
Why does the ionosphere make a great friend? It always reflects on what you said.
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References

Answer: The ionosphere. The ionosphere is a layer high in the atmosphere charged by the sun. It bends HF signals back to Earth, letting them travel very long distances.

  1. NOAA: Global D-Region Absorption Prediction Documentation swpc-drupal.woc.noaa.gov/content/global-d-region-absorption-prediction-documentation
    Long-range communications using high frequency (HF) radio waves (3 - 30 MHz) depend on reflection of the signals in the ionosphere.
    Checked 2026-10-09.

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