skywavepropagagtiota

Skywave propagation, also known as ionospheric propagation, is a radio wave propagation phenomenon that occurs when radio waves are reflected or refracted off the ionosphere, bouncing them back to Earth. This allows for long-distance communication beyond the line of sight. The ionosphere is a region of Earth's upper atmosphere, roughly between 60 and 1,000 kilometers (37 to 620 miles) above the surface, that is ionized by solar and cosmic radiation.

Different frequencies of radio waves behave differently within the ionosphere. Lower frequencies, such as those used in AM radio broadcasting, can be reflected by the ionosphere, enabling them to travel thousands of kilometers. Higher frequencies, like those used for FM radio and television, tend to pass through the ionosphere. Very high frequencies and ultra-high frequencies are generally not suitable for skywave propagation and are typically used for line-of-sight communication.

The effectiveness of skywave propagation varies significantly with time of day, season, and solar activity. During the day, the lower layers of the ionosphere are more dense due to solar radiation, which can absorb some radio waves. At night, these layers dissipate, allowing for better reflection of lower frequencies. Solar flares and other solar events can cause disturbances in the ionosphere, leading to temporary disruptions in skywave communication. Amateur radio operators extensively use skywave propagation for long-distance contacts.