High frequency
A radio wave, also called radio frequency (RF) radiation, is a wave in the form of electromagnetic radiation with wavelengths ranging from roughly a thousand kilometers to a millimeter, ie in the frequency range from several hundred Hz to several hundred GHz. Radio waves are used in communication technology to transfer information from a radio transmitter to one or more receivers. Radio waves were discovered by Heinrich Rudolf Hertz in 1886. The transmitter transmits via an antenna, directed or not, the radio waves, which are received by the receiver's antenna after propagation through space. The radio wave serves as a carrier for the information to be transmitted, which is present as a variation in the amplitude (AM) or in the frequency (FM). Due to the information contained in the radio wave, the wave is not exactly of one specific frequency, but covers a certain area, called a frequency band, around the frequency of the carrier wave.