FM broadcasting in the United States began in the 1930s at engineer and inventor Edwin Howard Armstrong's experimental station, W2XMN. The use of FM radio has been associated with higher sound quality in music radio.
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).
Citizens band radio, used in many countries, is a land mobile radio system, a system allowing short-distance person-to-person bidirectional voice communication between individuals, using two way radios operating on 40 channels near 27 MHz (11 m) in the high frequency band. Citizens band is distinct from other personal radio service allocations such as FRS, GMRS, MURS, UHF CB and the Amateur Radio Service. In many countries, CB operation does not require a license, and it may be used for business or personal communications. Like many other land mobile radio services, multiple radios in a local area share a single frequency channel, but only one can transmit at a time. The radio is normally in receive mode to receive transmissions of other radios on the channel; when users want to talk they press a "push to talk" button on their radio, which turns on their transmitter. Users on a channel must take turns talking. Transmitter power is limited to 4 watts in the US and the EU. CB radios have a range of about 3 miles (4.8 km) to 20 miles (32 km) depending on terrain, for line of sight communication; however, various radio propagation conditions may intermittently allow communication over much greater distances.
Medium frequency (MF) is the ITU designation for radio frequencies (RF) in the range of 300 kilohertz (kHz) to 3 megahertz (MHz). Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hectometer band as the wavelengths range from ten to one hectometer. Frequencies immediately below MF are denoted low frequency (LF), while the first band of higher frequencies is known as high frequency (HF). MF is mostly used for AM radio broadcasting, navigational radio beacons, maritime ship-to-shore communication, and transoceanic air traffic control.
A radiotelephone is a radio communication system for transmission of speech over radio. Radiotelephony means transmission of sound (audio) by radio, in contrast to radiotelegraphy, which is transmission of telegraph signals, or television, transmission of moving pictures and sound. The term may include radio broadcasting systems, which transmit audio one way to listeners, but usually refers to two-way radio systems for bidirectional person-to-person voice communication between separated users, such as CB radio or marine radio. In spite of the name, radiotelephony systems are not necessarily connected to or have anything to do with the telephone network, and in some radio services, including GMRS, interconnection is prohibited.
The FM broadcast band is a range of radio frequencies used for FM broadcasting by radio stations. The range of frequencies used differs between different parts of the world. In Europe and Africa and in Australia, it spans from 87.5 to 108 megahertz (MHz) - also known as VHF Band II - while in the Americas it ranges from 88 to 108 MHz. The FM broadcast band in Japan uses 76 to 95 MHz. The International Radio and Television Organisation (OIRT) band in Eastern Europe is from 65.8 to 74.0 MHz, although these countries now primarily use the 87.5 to 108 MHz band, as in the case of Russia. Some other countries have already discontinued the OIRT band and have changed to the 87.5 to 108 MHz band.
Campus radio is a type of radio station that is run by the students of a college, university or other educational institution. Programming may be exclusively by students, or may include programmers from the wider community in which the radio station is based. Sometimes campus radio stations are operated for the purpose of training professional radio personnel, sometimes with the aim of broadcasting educational programming, while other radio stations exist to provide alternative to commercial broadcasting or government broadcasters.
106.8 Time FM was a local commercial radio station located in the south-east London and north-west Kent area of England, which broadcast to Greenwich and Bexleyheath in London and Dartford and Gravesend in Kent on 106.8 FM, and ceased transmission in April 2009.
Pirate radio stations have operated in various countries of Asia, often putting over political or nationalist points of view. Offshore stations have attempted to reach China or overseas Chinese residents. Citizens' Radio is an unlicensed Hong Kong pro-democracy station. In Taiwan, what are known as "underground radio" stations have broadcast both pro- and anti-government opinions. Large numbers of unlicensed stations have functioned in the Philippines, of which 107.9 U-Radio (2006–2013) is among the best known. Finally, Radio First Termer was briefly operated by and for U.S. troops in Vietnam in 1971.
WMPG is a community radio station broadcasting from Portland, Maine. It is located on Bedford Street at the University of Southern Maine Portland Campus. It is affiliated with the college, and a mix of USM students and volunteers from the greater Portland community produce all the music and local public affairs programs. It broadcasts 4.5 kilowatts on 90.9 and can be heard as far north as Augusta, Maine and west into New Hampshire. It broadcasts streaming online 24/7 and the programming guide and contact info is available at their website along with many archived programs.
Travelers Information Stations (TIS), also called Highway Advisory Radio (HAR) by the United States Department of Transportation, are licensed low-powered non-commercial radio stations, used to broadcast information to the general public, including for motorists regarding travel, destinations of interest, and situations of imminent danger and emergencies. They are commonly operated by transportation departments, national and local parks departments and historic sites, airport authorities, local governments, federal agencies, colleges and universities, hospitals and health agencies, and for special events and destinations.
FM broadcasting is a method of radio broadcasting using frequency modulation (FM). Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high fidelity sound over broadcast radio. FM broadcasting is capable of higher fidelity—that is, more accurate reproduction of the original program sound—than other broadcasting technologies, such as AM broadcasting. Therefore, FM is used for most broadcasts of music or general audio. FM radio stations use the very high frequency range of radio frequencies.
CBFX-FM is a public non-commercial radio station in Montreal, Quebec. It is the flagship station of the Ici Musique Network and broadcasts in French.
CHYZ-FM is the college radio station for Université Laval, located in Sainte-Foy, Québec, Canada. Its frequency is 94.3 MHz on the FM dial.
WKHR – branded WKHR FM 91.5 – is a non-commercial educational adult standards/MOR radio station licensed to Bainbridge, Ohio. Owned by the Kenston Local School District, the station serves Geauga County and eastern parts of Greater Cleveland. The WKHR studios are located at Kenston Middle School in Bainbridge township, while the station transmitter resides in Newbury township.
A radio repeater is a combination of a radio receiver and a radio transmitter that receives a signal and retransmits it, so that two-way radio signals can cover longer distances. A repeater sited at a high elevation can allow two mobile stations, otherwise out of line-of-sight propagation range of each other, to communicate. Repeaters are found in professional, commercial, and government mobile radio systems and also in amateur radio.
In the United States, the CB Band Radio Service, or Citizens' Band ("CB"), known as the Class D Citizens' Radio Service before 1976, is one of several personal radio services defined by the FCC's Part 95 rules. It is intended to be a two-way voice communication service for use in personal and business activities of the general public, and has a reliable communications range of several miles, though the range is highly dependent on type of radio, antenna and propagation. Class A and B are no longer in existence. The former Class C, now known as the Radio Control Radio Service (RCRS) is a Radio Control ("R/C") model service and is covered further down in this article.
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by a radio receiver connected to another antenna. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing and other applications.
