ionospheric reflection
Quick Summary
The ionosphere is a region of Earth's atmosphere, starting around 50 km (30 miles) above the surface, where electrically charged particles, created by solar radiation, affect radio wave propagation. These charged particles, ions and electrons, are crucial for reflecting and bending radio waves back to Earth, extending transmission ranges far beyond line of sight.12
The ionosphere is divided into layers:
* D region: The lowest layer (70-90 km or 40-55 miles), which exists only during daylight. It absorbs medium and lower shortwave frequencies, limiting radio transmission range during the day.32
* E region: Located about 110 km (68 miles) high, it reflects radio waves and maintains some reflectivity for a few hours after sunset.2
* F region: The highest and most important layer, capable of reflecting higher frequencies. It often splits into F1 and F2 layers during the day (around 200 km and 400 km) and combines into a single layer at night (around 300 km).2
These layers vary in height and reflectivity due to changes in solar activity.4
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