Montage Acoustics Speakers: Stereo separation
Montage Acoustics BT4480: FM broadcast station frequency
The frequency of an FM broadcast station (more strictly its assigned nominal centre frequency) is usually an exact multiple of 100 kHz. In most of South Korea, the Americas and the Caribbean, only odd multiples are used. In some parts of Europe, Greenland and Africa, only even multiples are used. In Italy, multiples of 50 kHz are used. There are other unusual and obsolete standards in some countries, including 0.001, 0.01, 0.03, 0.074, 0.5, and 0.3 MHz. However, to minimise cross-channel interference, stations operating from the same or geographically close transmitters tend to keep to at least a 0.5 MHz frequency separation even when closer spacing is technically permitted, with closer tunings reserved for more distantly spaced transmitters as potentially interfering signals are already more attenuated and so have less effect on neighbouring frequencies.
United States
Despite FM having been patented in 1933, commercial FM broadcasting did not begin until the late 1930s, when it was initiated by a handful of early pioneer stations including W8HK, Buffalo, New York (now WTSS); W1XOJ/WGTR, Paxton Massachusetts (closed down about 1953); W1XSL/W1XPW/WDRC-FM, Meriden, Connecticut (now WHCN); W2XMN/KE2XCC/WFMN, Alpine, New Jersey (owned by Edwin Armstrong himself, closed down upon Armstrong's death in 1954); W2XQR/WQXQ/WQXR-FM, New York; W47NV Nashville, Tennessee (now WSM-FM); W1XER/W39B/WMNE, whose studios were in Boston but whose transmitter was atop the highest mountain in the northeast United States, Mount Washington, New Hampshire (shut down in 1948); W9XAO Milwaukee, Wisconsin (later WTMJ-FM, off air in 1950, returning in 1959 on another frequency). Also of note are General Electric stations W2XDA Schenectady and W2XOY New Scotland, New York—two experimental frequency modulation transmitters on 48.5 MHz—which signed on in 1939. The two were merged into one station using the W2XOY call letters on November 20, 1940, with the station taking the WGFM call letters a few years later, and moving to 99.5 MHz when the FM band was relocated to the 88-108 MHz portion of the radio spectrum. General Electric sold the station in the 1980s, and today the station is called WRVE.Montage Acoustics
Montage Acoustics reviews: AM "radiotelephone" transmission
The entrepreneurs who developed AM "radiotelephone" transmission did not anticipate broadcasting voice and music into people's homes. The term "broadcasting", borrowed from agriculture, was coined for this new activity (by either Frank Conrad or RCA historian George Clark) around 1920. Prior to 1920 there was no concept of "broadcasting", or that radio listeners could be a mass market for entertainment. Promoters saw the practical application for AM as similar to the existing communication technologies of wireless telegraphy, telephone, and telegraph: two-way person-to-person commercial voice service, a wireless version of the telephone. Although there were a number of experimental broadcasts during this period, these were mostly to provide publicity for the inventor's products. True radio broadcasting didn't begin until around 1920, when it sprang up spontaneously among amateur stations. AM remained the dominant method of broadcasting for the next 30 years, a period called the "Golden Age of Radio", until FM broadcasting started to become widespread in the 1950s. AM remains a popular, profitable entertainment medium today and the dominant form of broadcasting in some countries such as Australia and Japan.
Montage Acoustics HD9001
AM broadcasting
AM broadcasting is the process of radio broadcasting using amplitude modulation (AM). AM was the first method of impressing sound on a radio signal and is still widely used today. Commercial and public AM broadcasting is authorized in the medium wave band worldwide, and also in parts of the long wave and short wave bands. Radio broadcasting was made possible by the invention of the amplifying vacuum tube, the Audion (triode), by Lee de Forest in 1906, which led to the development of inexpensive vacuum tube AM radio receivers and transmitters during World War I. Commercial AM broadcasting developed from amateur broadcasts around 1920, and was the only commercially important form of radio broadcasting until FM broadcasting began after World War II. This period is known as the "Golden Age of Radio". Today, AM competes with FM, as well as with various digital radio broadcasting services distributed from terrestrial and satellite transmitters. In many countries the higher levels of interference experienced with AM transmission have caused AM broadcasters to specialize in news, sports and talk radio, leaving transmission of music mainly to FM and digital broadcasters. Montage Acoustics Speakers
Montage Acoustics BT4480:The first commercial FM broadcasting stations
The first commercial FM broadcasting stations were in the United States, but initially they were primarily used to simulcast their AM sister stations, to broadcast lush orchestral music for stores and offices, to broadcast classical music to an upmarket listenership in urban areas, or for educational programming. By the late 1960s FM had been adopted by fans of "Alternative Rock" music ("A.O.R.—'Album Oriented Rock' Format"), but it wasn't until 1978 that listenership to FM stations exceeded that of AM stations in North America. During the 1980s and 1990s, Top 40 music stations and later even country music stations largely abandoned AM for FM. Today AM is mainly the preserve of talk radio, news, sports, religious programming, ethnic (minority language) broadcasting and some types of minority interest music. This shift has transformed AM into the "alternative band" that FM once was. (Some AM stations have begun to simulcast on, or switch to, FM signals to attract younger listeners and aid reception problems in buildings, during thunderstorms, and near high tension wires. Some of these stations now emphasize their presence on the FM dial.)
