RADIO COMMUNICATION IN TUNNELS

FOR COMMUNICATION SYSTEMS REQUIRING CABLE SUSPENSION, ENGINEERS RESPONSIBLE FOR THE DESIGN OF STRUCTURES, SHOULD TAKE INTO ACCOUNT THE LOCATION OF THE TRANSMISSION LINE AT THE TIME THEY DETERMINE THE SECTIONS REQUIRED. THE AUTHORITIES WITH THE POWER TO ALLOCATE THE WORKING FREQUENCIES SHOULD, OTHER CONDITIONS BEING SATISFACTORY, ALLOCATE FOR PREFERENCE THOSE FREQUENCIES WHICH ARE BEST ADAPTED TO PROPAGATION IN A TUNNEL. THE CLIENT SHOULD GIVE PREFERENCE TO A TRANSMISSION SYSTEM WHICH COULD BE USED EVEN IF, BY ACCIDENT OR FOR SAFETY REASONS, ELECTRIC CURRENT SUPPLY SHOULD BE CUT OFF AND TO A SYSTEM WHICH WOULD NOT DETERIORATE WITH TIME IN A DAMP OR DUSTY ATMOSPHERE. FOR THE COVERING ABSTRACT OF THE CONFERENCE, SEE IRRD ABSTRACT NO. 102873.