Radio In The United States
Radio broadcasting has been used in the United States since the early 1920s to distribute news and entertainment to a national audience. In 1923, 1 percent of U.S. households owned at least one radio receiver, while a majority did by 1931 and 75 percent did by 1937. It was the first electronic " mass medium" technology, and its introduction, along with the subsequent development of sound films, ended the print monopoly of mass media. During the Golden Age of Radio it had a major cultural and financial impact on the country. However, the rise of television broadcasting in the 1950s relegated radio to a secondary status, as much of its programming and audience shifted to the new "sight joined with sound" service. Originally the term "radio" only included transmissions freely received over-the-air, such as the AM and FM bands, now commonly called "terrestrial radio". However, the term has evolved to more broadly refer to streaming audio services in general, including subscription sat ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Critical Hours
Critical hours for radio stations is the time from sunrise to two hours after sunrise, and from two hours before sunset until sunset, local time. During this time, certain American radio stations may be operating with reduced power as a result of Section 73.187 of the Federal Communications Commission's rules. Canadian restricted hours are similar to critical hours, except that the restriction results from the January 17, 1984, U.S.-Canadian AM Agreement. Canadian restricted hours are called "critical hours" in the U.S.-Canadian Agreement, but in the AM Engineering database, the FCC calls them "Canadian restricted hours" to distinguish them from the domestically defined critical hours. Canadian restricted hours is that time from sunrise to one and one-half hours after sunrise, and from one and one-half hours before sunset until sunset, local time. U.S. stations operate with restricted hours because of Canadian stations, and vice versa. Those radio stations that must lower their powe ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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List Of The Initial Commercial FM Station Assignments Issued By The Federal Communications Commission On October 31, 1940
This is a list of the first fifteen construction permits that were granted by the United States Federal Communications Commission (FCC) for commercial FM stations. These were all issued on October 31, 1940. Background On May 24, 1940, the FCC had announced the establishment, effective January 1, 1941, of an FM radio band operating on 40 channels spanning 42–50 MHz, with the first five channels (42.1 to 42.9 MHz) reserved for educational stations, and the other 35 (43.1 to 49.9 MHz) available for commercial operation. On October 31, 1940, the first 15 commercial station Construction Permit authorizations were issued. Many of the grantees already operated standard AM stations in the same community, and some had previous experience operating "high frequency band" stations, including high-fidelity "Apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics) A-Bomb Abomination Absorbi ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Citizens Band Radio
Citizens band radio (CB radio) is a land mobile radio system, a system allowing short-distance one-to-many bidirectional voice communication among individuals, using two-way radios operating near 27 MHz (or the 11-m wavelength) in the high frequency or shortwave band. Citizens band is distinct from other personal radio service allocations such as FRS, GMRS, MURS, UHF CB and the Amateur Radio Service ( "ham" radio). In many countries, CB operation does not require a license and 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 communicate they press a "push to talk" button on their radio, which turns on their transmitter. Users on a channel must take turns transmitting. In the US and Canada, and in the EU and th ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Single Sideband
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of signal modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently. Amplitude modulation produces an output signal the bandwidth of which is twice the maximum frequency of the original baseband signal. Single-sideband modulation avoids this bandwidth increase, and the power wasted on a carrier, at the cost of increased device complexity and more difficult tuning at the receiver. Basic concept Radio transmitters work by mixing a radio frequency (RF) signal of a specific frequency, the carrier wave, with the audio signal to be broadcast. In AM transmitters this mixing usually takes place in the final RF amplifier (high level modulation). It is less common and much less efficient to do the mixing at low power and then amplify it in a li ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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American Forces Network
The American Forces Network (AFN) is a government television and radio broadcast service the United States Armed Forces provides to soldiers stationed or assigned overseas, and is headquartered at Fort Meade in Maryland. AFN comprises two subordinate overseas commands and one directorate in the continental United States. Overseas, AFN Europe is headquartered at Sembach Kaserne in Germany and consists of 15 subordinate stations in the countries of Bahrain, Belgium, Cuba, Germany, Greece, Italy, Spain, and Turkey. AFN Pacific is headquartered at Yokota Air Base in Japan and consists of nine stations in Diego Garcia, Japan, and South Korea. Stations under AFN Europe and AFN Pacific broadcast live local radio shows 12 hours a day Monday through Friday, with the exception of U.S. federal holidays. Stateside, AFN's broadcast operations, which include global radio and television satellite feeds, emanate from the AFN Broadcast Center/Defense Media Center at March Air Reserve Base in ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Voice Of America
Voice of America (VOA or VoA) is an international broadcasting network funded by the federal government of the United States that by law has editorial independence from the government. It is the largest and oldest of the American international broadcasters, producing digital, TV, and radio content in 48 languages for affiliate stations around the world.* * by * Its targeted and primary audience is non-Americans outside the American borders, especially those living in countries without press freedom or independent journalism. VOA was established in 1942, during World War II. Building on American use of shortwave radio during the war, it initially served as an anti-propaganda tool against Axis misinformation but expanded to include other forms of content like American music programs for cultural diplomacy. During the Cold War, its operations expanded in an effort to fight communism and played a role in the decline of communism in several countries. Throughout its operation ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Religious Broadcasting
Religious broadcasting, sometimes referred to as faith-based broadcasts, is the dissemination of television and/or radio content that intentionally has religious ideas, religious experience, or religious practice as its core focus. In some countries, religious broadcasting developed primarily within the context of public service provision (as in the UK), whilst in others, it has been driven more by religion, religious organisations themselves (as in the United States). Across Europe and in the US and Canada, religious broadcasting began in the earliest days of radio, usually with the transmission of religious worship, preaching or "talks". Over time, formats evolved to include a broad range of styles and approaches, including radio and television drama, documentary, and chat show formats, as well as more traditional devotional content. Today, many religious organizations record sermons and lectures, and have moved into distributing content on their own web-based IP channels. Re ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Brokered Programming
Brokered programming (also known as time-buy and blocktime) is a form of broadcast content in which the show's producer pays a radio or television station for air time, rather than exchanging programming for pay or the opportunity to play spot commercials. A brokered program is typically not capable of garnering enough support from advertisements to pay for itself, and may be controversial, esoteric or an advertisement in itself. Overview Common examples Common examples are religious and political programs and talk-show-format programs similar to infomercial on television. Others are hobby programs or vanity programs paid for by the host and/or their supporters, and may be intended to promote the host's personality, for instance in preparation for a political campaign, or to promote a product, service or business that the host is closely associated with. A live vanity show may be carried on several stations by remote broadcast or simulcast, with the producer paying multiple statio ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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WWV (radio Station)
WWV is a Shortwave radio, shortwave ("high frequency" or HF) radio station, located near Fort Collins, Colorado. It has broadcast a continuous time signal since 1945, and implements United States government frequency standards, with transmitters operating on 2.5, 5, 10, 15, 20, and 25 Hertz, MHz. WWV is operated by the U.S. National Institute of Standards and Technology (NIST), under the oversight of its Time and Frequency Division, which is part of NIST's Physical Measurement Laboratory based in Gaithersburg, Maryland. The term WWV is not an abbreviation and does not stand for anything (see WWV (radio station)#Establishment, below). WWV was established in 1919 by the Bureau of Standards in Washington, D.C., making it one of the oldest continuously-operating radio stations in the United States. NIST celebrated WWV's centennial on October 1, 2019. In 1931, the station relocated to the first of three suburban Maryland sites, before moving to a location near Fort Collins i ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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Time Signal
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, audible signals (even signal guns) have limited range. Busy seaports used a visual signal, the dropping of a ball, to allow mariners to check the chronometers used for navigation. The advent of electrical telegraphs allowed widespread and precise distribution of time signals from central observatories. Railways were among the first customers for time signals, which allowed synchronization of their operations over wide geographic areas. Dedicated radio time signal stations transmit a signal that allows automatic synchronization of clocks, and commercial broadcasters still include time signals in their programming. Today, global navigation satellite systems ( GNSS) radio signals are used to precisely distribute time signals over much of the w ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |
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World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks in World War II, Tanks and Air warfare of World War II, aircraft played major roles, enabling the strategic bombing of cities and delivery of the Atomic bombings of Hiroshima and Nagasaki, first and only nuclear weapons ever used in war. World War II is the List of wars by death toll, deadliest conflict in history, causing World War II casualties, the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Allied-occupied Germany, Germany, Allied-occupied Austria, Austria, Occupation of Japan, Japan, a ... [...More Info...]       [...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]   |