Radio is a technology used for signal transmission and modulation

Radio is a technology used for signal transmission and modulation by electromagnetic radiation (electromagnetic waves). This wave passes and travel by air and can also travel through the vacuum of space, because this wave does not require the carrier medium (such as air molecules).

Radio waves are a form of electromagnetic radiation, and is formed when electrically charged objects is modulated (increased frequency) at frequencies contained in the radio frequency (RF) in an electromagnetic spectrum, and electromagnetic radiation moves by way of oscillating electric and magnetic.

Other electromagnetic waves, which have frequencies above the radio waves include gamma rays, X-rays, infrared, ultraviolet, and visible light.

When the radio waves transmitted through the cable, the oscillation of electric and magnetic fields are expressed in the form of alternating current and voltage on the cable. This can then be converted into an audio signal or any other that carries information.

Act No. 32 of 2002 on Broadcasting states that radio frequencies are electromagnetic waves used for broadcasting and propagating in air and space without artificial means of Conductor, is a public domain and limited natural resources. Like other electromagnetic spectrum, radio waves propagate with a speed of 300,000 miles per second. It should be noted that different radio waves with audio wave.

Radio waves propagate at a frequency of 100.000 Hz to 100,000,000,000 Hz, while the audio waves propagate at a frequency of 20 Hz to 20,000 Hz. In radio broadcasting, audio wave is not transmitted directly but superimposed on the radio waves that will propagate through space. There are two methods of transmitting audio, namely through amplitude modulation (AM) and frequency modulation (FM).

Although the word 'radio' is used for matters relating to the receiver of sound waves, but wave transmission is used as the basis of the wave on television, radio, radar, and mobile phones in general.

Pointing to a radio frequency electromagnetic spectrum in which electromagnetic waves can be generated by the flow of back and forth to an antenna. Frequencies as part of the spectrum is included below:


absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere effectively become "opaque" to a higher frequency of electromagnetic radiation, until the atmosphere becomes transparent again in the so-called term frequency infrared and optical window.

Band ELF, SLF, Ulf, and VLF spectral overlap with AF, approximately 20 to 20.000 Hz. However, the sound transmitted by atmospheric compression and development, and not by electromagnetic energy.

Electrical Connectors are designed to work on radio frequencies known as the Liaison RF. RF is also the name of connecting audio / video standard, which is also called a BNC (Bayonet Neill-Concelman).