If you type in a search engine the word radio, you'll see several definitions of the term. For example: The radio – a device that provides two-way communication at a distance. A well-known Internet encyclopedia "Wikipedia" gives the following definition: The radio – portable radio receiving and transmitting low and medium power. You can also find another option: The radio – is short for radio. The term portable radio has a narrower meaning – Under-talkies meant only stationary or car radios and walkie-talkies, receiving and transmitting sound. So what is the radio? The operation is the use of radio waves. Radio waves – is electromagnetic waves propagating through space at light speed. Radio waves carry through space energy emitted by the generator of electromagnetic waves.
And when they are born changing electric field, for example, when the conductor passes through the alternating electrical current through the space, or when sparks swaps, ie, number of fast successive current pulses. Electromagnetic radiation is characterized by frequency, wavelength and power of the transmitted energy. Frequency electromagnetic waves shows how many times per second change in the direction of the radiator of electric current and, consequently, How many times per second varies at each point of the magnitude of the electromagnetic field. The first inventor of the transmission and reception of electromagnetic waves (which for a long time called "Hertz Waves") a German scientist Heinrich Hertz (1888). Frequency is measured in hertz (Hz), 1 Hz – this is one oscillation per second, one megahertz (MHz) – one million cycles per second.