Radio waves are electromagnetic waves that travel at the speed of light. They are the propagation of an oscillating electric and magnetic field oriented perpendicular to each other. When radio waves propagate through the atmosphere, extra attenuation processes come into play in addition to the inverse square law, that is, absorption and scattering. Non‐ionospheric propagation can be subdivided according to frequency into surface waves and space waves. The most basic radio communication system that can be used to send messages in Morse code is schematically illustrated. There are two basic types of digital modulation used in aviation, which is pulsed modulation where the carrier is emitted as a set of precisely timed pulses, or phase shift modulation where the carrier amplitude is continuous but its phase or frequency is shifted. The radiation emitted by an oscillating current in a wire and how it propagates are described by Maxwell's equations.
Radio Propagation and Communication
Aircraft Systems ; 167-248
2018-11-09
82 pages
Article/Chapter (Book)
Electronic Resource
English
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