NIOSHTIC-2 Publications Search
Improvements for Mine Carrier Phone Systems. Technical Services for Mine Communications Research.
Spencer-RH; Emslie-AG; Foulkes-JD; Et Al
NTIS: PB 273 292 Available for Reference At Bureau Libraries :175 pages
Based on interviews and discussions with knowledgeable people, laboratory experiments, and in-mine measurements, it was determined that the major impediment to good carrier phone system performance is the extreme signal attenuation found on the trolley wire-rail largely caused by the many bridging loads. Three means are identified to help overcome the performance difficulties: the low impedance trolley wire, a method of improving performance by capacitively loading the transmission line; the dedicated wire, a low-loss means of extending trolley signal coverage; and the use of isolators to remove the offending bridging loads at the carrier frequency. Other subjects treated in the report are design reviews of hardware, guidelines for the use of information in the report, recommendations, and a description of a probe for measuring trolley wire current.
CP; Final Contract Report;
NTIS Accession No.
NTIS: PB 273 292 Available for Reference At Bureau Libraries
A. D. Little, Inc.
Page last reviewed: March 11, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division