I have decided to focus on radio waves, which have the lowest frequency on the electromagnetic spectrum. Radio waves are any kind of electromagnetic wave formed by a current in a wire or a circuit. AM (amplitude modulation) and FM (frequency modulation) differ in how they carry information and what their transmission sites look like. AM radio waves have varying amplitudes and their antennas are constructed to be quite tall (so they can transmit waves at their preferred size of /2). Due to their larger amplitudes, they can often travel over hills and other obstructions.

FM radio waves are carrier waves with audio signals of identical amplitudes added to them in order to send information about sound. In television, the FM audio signals are extremely important and often much more complex than they would be for radio, which requires a large range of frequencies to be transmitted. Satellite dishes, cable, and HD formats are carried at much higher frequencies to be able to carry even more information about the television audio. FM transmission towers are normally smaller than AM transmission towers because their amplitudes do not vary, but they are elevated to achieve a direct 'line of sight' between the antenna and the receiver.

In responding to the above posts, aim to restate your understanding of how this EM instrumentation works. Include an outside citation in at least one of your responses.