Radio wave propagation can be classified into three main types: earth wave propagation, sky wave propagation, and space wave propagation. Earth wave propagation follows the curvature of the Earth and is typically used for shorter distances at lower frequencies. Skywave propagation involves the reflection of radio waves from the ionosphere, enabling long-distance communication, particularly at medium frequencies.
Space wave propagation occurs at higher frequencies and involves line-of-sight transmission between antennas.
The three types of radio waves are classified by their frequencies: very low frequency (VLF), medium frequency (MF), and ultra high frequency (UHF). VLF waves have long wavelengths and can penetrate deep into water and soil. MF waves are used for AM radio broadcasts and have a longer range than higher frequencies.
UHF waves have short wavelengths and are used for television broadcasting and cellular networks.
The mechanisms of radio wave propagation include reflection, refraction and diffraction. Reflection occurs when radio waves bounce off a surface, such as the ionosphere or the ground. Refraction involves the bending of radio waves due to changes in the medium, such as the ionosphere. Diffraction occurs when waves bend around obstacles, allowing signals to reach the line of sight.
The three commonly discussed types of propagation modes are ground wave mode, sky wave mode, and line of sight mode.
The Earth wave mode follows the Earth’s surface and is effective at lower frequencies. Sky Wave mode uses the ionosphere for long-distance communication. Line of sight mode requires line of sight between transmitting and receiving antennas, typically used at higher frequencies for shorter distances.
Technologies using radio waves include radio broadcasting, where AM and FM frequencies are used for audio transmission. Cellular networks use radio waves for mobile communication, enabling voice calls, messaging, and Internet access.
Satellite communication relies on radio waves for data transmission between earth stations and orbiting satellites, facilitating global connectivity and broadcasting services