Define Radio Broadcasting

Radio broadcasting is a distinctive form of media.

To "broadcast" means to transmit or put out. In radio broadcasting the thing transmitted is a radio signal. Radio broadcasting is the distribution of news and entertainment audio programs (consisting of talk music, and other sounds) through radio waves to an audience. The audience is made up of any and everyone with a radio receiver who tunes in to a radio station broadcast.

History

Radio broadcasting technology evolved from efforts to develop "wireless" telegraphy systems. The start of what we recognize today as commercial radio broadcasting began to form around 1923, becoming more firmly established between 1926 and 1930. Radio broadcasters produce and transmit programs that may contain a mix of music, news, discussion, voice-over dramas and voice advertisements.

Transmission

Radio stations broadcast their programming through radio waves. The most important pieces of equipment needed to operate a radio station are the transmitter and antenna. The transmitter is connected to the antenna; it sends an electrical signal up and down the antenna wire, generating the station's carrier wave frequency. The audio information from the radio programming is encoded into the radio carrier wave, producing a radio signal. Encoding information in a radio carrier wave is a simple matter of using the sound waves from the radio program to modulate either the amplitude or frequency of the baseline carrier wave. This modulated signal is what gets broadcast "over the air."

Reception

Radio receivers are used to pick up radio broadcasting signals. When you "tune in" to a particular radio station, you are actually setting your radio dial to the radio station's carrier wave frequency. The antenna on your receiver detects this radio signal. Your radio receiver then works to demodulate the signal, allowing you to hear the encoded audio information. Every time the receiver detects a modulation in the carrier wave frequency, it generates a corresponding motion in the speaker cone located in your speakers. This motion reproduces the original sound wave of the radio program.

Types

The two basic types of radio broadcasting are AM and FM. AM stands for amplitude modulation. FM stands for frequency modulation. AM and FM denote which type of modulation was used to produce a radio signal. HD radio and satellite radio are both relatively new forms of radio broadcasting. With HD radio, radio stations are able to broadcast a digital (rather than analog) radio signal; or they may choose to broadcast a hybrid (simulcast) of both digital and analog versions of their radio signal. Satellite radio is also digital. But instead of being broadcast by antenna, satellite radio is broadcast through a communications satellite that gives it a wider broadcast range.

Identification

Television broadcasting, amateur radio communication, citizen band (CB) and general mobile radio service (GMRS) and walkie-talkie communication, as well as other forms of wireless communications are all built around the capacity to encode information in radio waves. But even though these industries and technologies use radio waves, they are not considered forms of radio broadcasting. Radio broadcasting is a definition reserved to the industry of radio broadcast stations.

References

• National Radio Astronomy Observatory: How Radio Communication Works
• Through the Wires: Broadcasting
• Georgia State University: Broadcast Signals
• KJZZ FAQs: What is HD Radio

Resources

• Northwestern University: How is Data Put on Radio Waves?