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- Medium frequency communications systems
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Results 11 - 20 of 25
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11/19/2014 - Contracts and cooperative agreementsA contract to increase the performance of medium frequency communications in underground mines.
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7/22/2014 - Interagency agreementsAn interagency agreement to design and develop a subterranean wireless electronic communications system for the U.S. Army.
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9/1/1986 - Contract reportsThis report describes the creation of an efficient method to determine if command, control, communication, and monitoring (3cm) equipment in coal, metal, and nonmetal mines is susceptible to radio frequency interference (RFI) from the medium-frequency (...
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7/1/1985 - Peer reviewed journal articlesMedium frequency (MF) techniques have been successfully applied to the problem of radio voice communications in both coal and metal and nonmetal mines. MF techniques can also be applied to the areas of in-mine control and monitoring. Preliminary work in...
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9/1/1984 - Contract reports, Open File ReportsThis report deals with information regarding a new Medium Frequency (MF) Wireless Communication System for underground mines. This new telecommunication system works on low loss electromagnetic wave propagation modes which allow it to provide quality ra...
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1/1/1984 - Conference papersTheoretical and experimental research sponsored by the U.S. Bureau of Mines shows that medium frequency (MF) electromagnetic (EM) signals propagate great distances in an underground environment such as a tunnel or mine. This propagation is enhanced by d...
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1/1/1983 - Contract reportsAn underground medium frequency radio communications system has been developed and demonstrated in both coal and metal/non metal mines. The principal advantage of the system are its low cost, ease of installation and the ability to provide radio communi...
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7/1/1982 - Conference papersA medium-frequency (MF) communication system has been built and has been tested in underground mines. It provides radio coverage to vehicles and personnel anywhere in the mine via parasitic coupling into existing mine conductors.
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7/1/1979 - Contract reports, Open File ReportsThis report describes a complete system design for medium frequency ( MF) wireless radio systems for use in coal mines. The emphasis is on AC mines where no trolley wire exists and, for which, conventional trolley phone communications cannot be used. Th...
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10/1/1978 - Contract reportsThis document describes the decision factors that bear on the selection of the modulation process for the wireless underground medium frequency (MF) communication system.
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Content source: National Institute for Occupational Safety and Health, Mining Program