Sky wave propagation is a method of transmitting and receiving radio waves that uses the ionosphere to reflect signals back to Earth. This type of propagation is used for long-distance communication, especially in the medium and high frequency bands.
In sky wave propagation, a radio signal is transmitted into the sky at a high angle, and it travels upward into the ionosphere. The ionosphere reflect the radio signal back to Earth, allowing it to be received at a distance far beyond the line of sight.
The distance that a signal can travel using sky wave propagation depends on several factors, including the frequency of the signal, the angle of transmission, and the properties of the ionosphere. In general, higher frequencies are more likely to pass through the ionosphere and be lost in space, while lower frequencies are more likely to be reflected back to Earth.
Sky wave propagation is an important technique for long-distance communication. However, it is susceptible to interference and variability, and it is being gradually replaced by satellite and other technologies for long-distance communication.