Inductive loop communication systems

Claim 1

A TWO-WAY COMMUNICATION SYSTEM COMPRISING A FIXED TRANSMITTER-RECEIVER STATION, AT LEAST ONE MOVABLE TRANSMITTER-RECEIVER STATION, A STATIONARY AMPLIFIER FORMING PART OF SAID FIXED STATION, A FIRST INDUCTIVE LOOP, SAID FIRST LOOP CONSISTING OF SPACED CONDUCTORS LOCATED ALONG THE PATH OF MOVEMENT OF SAID MOVABLE STATION AND CONNECTED IN PARALLEL, SAID PARALLEL CONNECTION AT ONE END INCLUDING A CENTRE-TAPPED WINDING AND AT THE OTHER END A DIRECT CONNECTION BETWEEN SAID SPACED CONDUCTORS, A SECOND INDUCTIVE LOOP, A PART OF SAID SECOND LOOP COMPRISING THE PARALLED CONDUCTORS OF SAID FIRST LOOP CONNECTED IN SAID SECOND LOOP BY WAY OF SAID CENTRE-TAP AND SAID DIRECT CONNECTION, MEANS FEEDING OUTPUT SIGNALS FROM SAID AMPLIFIER INTO SAID SECOND LOOP SO THAT SAID SIGNALS PASS IN PARALLEL THROUGH THE CONDUCTORS CONSTITUTING SAID FIRST LOOP, A WINDING INDUCTIVELY ASSOCIATED WITH SAID CENTRE-TAPPED WINDING FOR APPLYING SIGNALS CIRCULATING IN SAID FIRST LOOP ONLY TO THE INPUT OF SAID AMPLIFIER, AND MEANS PREFERENTIALLY COUPLING SAID MOVABLE STATION TO ONE ONLY OF SAID PARALLELLED CONDUCTORS OF SAID FIRST LOOP.