émetteur pour filon-couche

OBS: D'après M. Wayne Alder, de l'Association minière du Québec, il s'agit d'un émetteur utilisé dans les mines de charbon pour mesurer la conductivité du gisement.

CONT: This exemption shall apply to the following electrical equipment only: Model IS-2 in-seam transmitter.
OBS: Coal seams are well known conductor of radio frequency signals owing to the large conductivity contrast between the coal ... and the host rocks ... which results in a waveguide effect when both the transmitter and receiver are in seam.