↑ What are the modes of HF Radio Propagation?

Edited by Doron Tal, 4X4XM
The modes of HF radio propagation are:
  1. Line Of Sight propagation: Line of sight refers to the propagation of HF radio waves in a straight line without being reflected by the ground or other objects. Such signals can travel for relatively short distances, depending on terrain and atmospheric conditions.
     
  2. Ground wave propagation: The radio signal travels over the Earth's surface and is absorbed and reflected by the ground in this mode of propagation. Ground wave propagation is most effective at lower frequencies (below 2 MHz) and can be used for short-range communication, typically up to a few hundred kilometers.
     
  3. Sky wave propagation: This is the mode of propagation in which the radio signal is reflected by the ionosphere and returns to Earth. Sky wave propagation is most effective at higher frequencies (3-30 MHz) and can be used for long-range communication, typically up to several thousand kilometers.
     
  4. Ionospheric scatter propagation: In this mode of propagation, the radio signal is scattered by the ionosphere and received by another station within the scatter region. This mode of propagation is best suited for medium-range communication at frequencies ranging from 20 to 50 MHz.
The mode of propagation used depends on several factors, including the frequency of the radio signal, the distance between the transmitting and receiving stations, the time of day, and the environmental conditions. Understanding the most effective mode of propagation for a given situation is important for optimizing HF radio communication and ensuring reliable transmission.

You may find more detailed information in the main webpage, here. See also an index for HF Radio Propagarion.