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Спереводом: principles of radio communications developing an understanding of radio communications begins with the comprehension of basic electromagnetic radiation. radio waves belong to the electromagnetic radiation family, which includes x-ray, ultraviolet, and visible light — forms of energy we use every day. much like the gentle waves that form when a stone is tossed into a still lake, radio signals radiate outward, or propagate, from a transmitting antenna. however, unlike water waves, radio waves propagate at the speed of light. radio wave amplitude, or strength, can be visualized as its height — the distance between its peak and its lowest point. amplitude, which is measured in volts, is usually expressed in terms of an average value called root-mean-square, or rms.