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Intermediate and Radiofrequency Sources and Exposures in Everyday Environments
Published in Ben Greenebaum, Frank Barnes, Bioengineering and Biophysical Aspects of Electromagnetic Fields, 2018
FM radio broadcasting commonly uses a frequency range, differing by country, within the very-high frequency (VHF) band, from 30 to 300 MHz (ITU, 2007). Antenna towers, which are not part of the transmitting system, are usually high and emissions are directed to reach longer distances. Mean exposure levels of the population are around 0.1 V/m although a small proportion of subjects can be exposed to up to 2 V/m. Workers in the surroundings of a tower can be exposed to up to 800 V/m while in the proximity to the emitting antenna, levels can reach 1,000 V/m and about 5 A/m (Allen et al., 1994; Mantiply et al., 1997; Moss and Conover, 1999).
Types of Broadcasting
Published in Skip Pizzi, Graham A. Jones, A Broadcast Engineering Tutorial for Non-Engineers, 2014
Traditional radio broadcasting for local stations in the United States and throughout the world generally falls into two main types: AM and FM—standing for amplitude modulation and frequency modulation, respectively. These are the particular methods of radio transmission used for many years in broadcasting audio signals to home, car, and portable receivers. In North America, AM is used in the medium frequency (MF)—also known as medium wave band—whereas FM uses the very high-frequency (VHF) band.
Modernizing a nation through its radio and television industry: RCA Victor in Chile, 1928-1973
Published in History and Technology, 2021
Francisco Garrido, Ricardo Paredes
The arrival of the RCA Victor company in Chile is intimately related to the introduction of radio broadcasting in the country. Radio broadcasting in Chile started in Santiago in August 1922, but it only became widely popular in the 1930s. Its popularity was stimulated by technical regulations in terms of frequency assignments, limitations in signal strength to reduce interference, daily broadcasting schedules, the licensing of broadcasting companies, and a formalized market for radio receivers.19 An American commercial report on Chile in 1927 described that most radio sets were imported from US and Germany, and included the following about radio broadcasting: About three years ago keen interest was shown in radio in various parts of Chile. Sales of radio sets and parts were active in both urban and rural districts; several broadcasting stations offered programs of dance music from phonographs and announcements of items of public interest … Broadcasting programs are largely limited to announcements of the newspapers or to matters of an advertising or political nature and to phonograph music, although one station in Santiago is now broadcasting the music of an orchestra in one of the motion-picture houses. 20
ICTs, Empowerment, and Success: Women’s Perceptions across Eight Countries
Published in Journal of Computer Information Systems, 2021
Fatih Çetin, Tara Urich, Joanna Paliszkiewicz, Magdalena Mądra-Sawicka, Jeretta Horn Nord
ICTs help people to structure their lives around the possibilities it provides – this process is called digitalization.9 Information and Communication Technologies (ICT) are identified as a means to promote economic and social development by decreasing the cost and increasing the efficiency of communication and cooperation. ICTs include a complex, heterogeneous, and interrelated set of goods, applications, and services used to produce, process, distribute, and transform information.10 They include the outputs of industries as diverse as telecommunications, television and radio broadcasting, computer hardware and software, computer services, and electronic media.11 These digital technologies influence the social norms and values by changing the exposure to different ways of life.12
Vaunting the independent amateur: Scientific American and the representation of lay scientists
Published in Annals of Science, 2018
Who were the postwar adult counterparts of these young enthusiasts? At war’s end, adults were able to return in much-increased numbers to the independent pursuit of scientific hobbies that had been the hallmark of the interwar period, many of them with practical training in mechanics, electronics and optics. In the early postwar years, fed by low-cost components and increasing leisure time, new technical hobbies – electronics, ham radio, model aircraft, hot-rodding – exploded in popularity.60 Amateur radio boomed from 1946, when wartime government restrictions on shortwave radio broadcasting were lifted.61 A Science Service broadcast suggested that many hobbyists were ex-servicemen who, as during the previous war, had been trained as technicians or operators. And a considerable fraction of the amateurs tempted into science hobbies before the war returned to it, raising the average age of licensed radio amateurs from 22 to 30 years old. They came from all walks of life: ‘students, financiers, newsboys, princes, miners, motion picture stars, airplane pilots, farm hands, concert pianists, famous doctors and newspaper men’. One in 35 of them were women although, as relative outsiders, they still had to contend with the Morse-code moniker YL (for ‘young lady’) or XYL (‘ex-young lady’, meaning married). Building 95% of their own transmitting equipment, the qualities of such hobbyists again emphasized hands-on expertise and national benefit: ‘The amateur is an experimenter … Not hesitating to tackle problems that he has not heard were insoluble, he frequently turns up with the answer’.62