The massive increase of wireless communications in the world calls for responsible actions by governments in order to prevent possible health hazards. In addition to cellular towers overcrowding in urban areas, it is also important to consider other radio frequency radiations from different sources. The electric field intensity is one of the fundamental parameters to assess the exposure of human beings to Non-Ionizing Radiation (NIR). In this study, all main non-ionizing radiation sources in the urban area of Natal, Brazil (a city of about 860.000 inhabitants) were located and characterized with respect to frequency band, telecommunications service and integrated electric field strength. Measurements of far electric field intensity with frequency ranging from 30 MHz to 3 GHz were made in a survey of 140 outdoor points spread across all the 167.26 km2 area of the city. The results obtained have made it possible to draw a map of the regions of the city according to different electric field and ER intensities. In 71.4% of the sampled outdoor points, the highest Exposure Ratio measured were originated from TV broadcasting services, 22.1% from Transmissions Cellular Towers and 6.4 % from Frequency Modulated Broadcasting .

The Electric Field Intensity is one of the fundamental parameters to assess the exposure of human beings to Non-Ionizing Radiation (NIR). Although the major concern of environmental control bodies is with mobile telecommunication systems, this work highlights the attention which should also be given to the radiation emitted by television broadcast towers, which utilize higher power levels with continuous emissions.Measurements of downlink far electric field intensity with frequency ranging from 30 MHz to 3 GHz were made in a survey of 160outdoor points spread across all the 170 km2 area of Natal (a city of about 853.000inhabitants in northeast Brazil). The results obtained indicate that in 73.6% of the sampled outdoor points, the highest downlink electric field intensitiesmeasured were originated from TV broadcasting services, compared to 20.1% from Mobile SystemsTowers, 6.3% from Frequency Modulated Broadcasting and 0% from WLAN (IEEE 802.11bg). Based on these findings, a model is presented to estimate the intensity of the mean electric field at any given point of the city’s urban area generated by TV radiation emissions at VHF and UHF bands. Four distinct areas of the city were considered, basically adjusted to the azimuths related to the main tower concentration place. The modeling was done using the Statistical Multivariate Regressiontechnique, the Electric Field Strength was the dependent variable, the independent variables were the Distances of points to the transmission towers. Database was used with samples of measured values of Electric Field and their Distances to the TV transmission towers. The solution reached to estimate the electric field can be adapted for use in other cities. Detailed mapping of the electric field intensitiesmayensurebetter preventive conditions to monitor the degree of NIR exposurein each area and simplify evaluation procedures for the licensing of telecommunication stations.

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RESUMO A TV aberta é um importante ator de comunicação na sociedade contemporânea com alguns padrões de sucesso, entre eles o Sistema Brasileiro de Televisão Digital Terrestre (SBTVD-T). Este artigo discute aspectos relacionados à construção de um projeto técnico para obtenção de outorgas para o serviço de televisão e seus serviços ancilares no Brasil. Apresentamos algumas ferramentas de livre acesso que podem ser utilizadas para realizar tal atividade. Por fim, um estudo de caso apresenta a construção do projeto técnico da TV Universitária, uma emissora de TV da Universidade Federal do Rio Grande do Norte, Brasil. Como principal resultado, pretendeu-se preencher a lacuna de material técnico relacionado ao uso de ferramentas abertas e bases de dados governamentais para a construção de projetos técnicos de TV digital no Brasil.

RESUMOO serviço de radiodifusão sonora e de imagens continua sendo um dos principais veículos de mídia e informação da sociedade contemporânea e vem passando por um longo processo de alteração de seus aspectos regulatórios decorrente da implantação do Sistema Brasileiro de Televisão Digital Terrestre (SBTVD-T). Este artigo apresenta e discute os procedimentos para obtenção de outorgas para o serviço de televisão e seus serviços ancilares no Brasil. Como resultado principal, pretendeuse preencher a lacuna por material técnico relacionado à discussão da legislação da TV digital no Brasil.