Device for detecting person in hazard area, especially in mine, has portable transmitter-receiver with 2 transmitters and 2 receivers; one receiver has 3 orthogonal independent coils operating at 9 KHz, one has one coil operating at 7 KHz

摘要

The device consists of a transmitter-receiver (7) for electromagnetic waves worn by a person and a spatially separate transmitter-receiver for activating it. The portable transmitter-receiver has two transmitters (5,6) and two receivers (1-3,4). One receiver has three mutually orthogonal, independent coils (1-3) operating at 9 KHz and the other has one coil (4) operating at 7 KHz. One transmitter operates at 455 KHz and the other at 433 KHz.