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- Contract reports
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Results 31 - 40 of 74
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10/1/1980 - Contract reportsThe object of this program was to extend the capabilities of visual paging systems both in size and functions in mines. The system developed uses the mine pager phone line for communication, monitoring, and remote control. The system was designed to be ...
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9/1/1980 - Contract reportsThis report adds to the current body of underground communications system design knowledge by: accurately defining (measuring) the 12 dB SINAD sensitivity of the system receivers and then stating the equivalent magnetic field strength in uA/m; showing t...
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7/1/1980 - Contract reportsThis report assesses the expected detectability, on the surface above mines, of electromagnetic signals produced in the 630- to 3,030-hz frequency band by a rescue transmitter activated by miners trapped underground. The implications of the results and ...
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6/1/1980 - Contract reportsThe objective of this project was to develop technical data and evaluate performance and utility of leaky feeder communications systems currently used in U.S. underground mines.
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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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1/15/1979 - Contract reportsCharacteristics of metal-nonmetal mines were evaluated to determine the suitability of applying the Bureau of Mines electromagnetic (em) location system to locating trapped miners.
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1/1/1979 - Contract reportsThis report presents a mathematical model for the propagation of UHF radio waves in the large cross section tunnels of a room-and-pillar limestone mine and describes the analysis of a small amount of propagation data obtained. The model and analysis is ...
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1/1/1979 - Contract reportsThis report contains a summary of analytical research on electromagnetic methods of nondestructive testing of cylindrical conductors. The principal objective is to provide theoretical insight to the operation of electromagnetic sensing of the internal p...
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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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9/1/1978 - Contract reportsThis report covers antenna design, analysis, and development work suited for use with a wireless radio communication system operating at medium frequency. The work includes the test and evaluation of prototype vehicular antennas developed during the pro...
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Content source: National Institute for Occupational Safety and Health, Mining Program