INDUCTION LINE DEVICE FOR MEDIUM WAVE BROADCASTING

摘要

PURPOSE:To prevent interference between a prescribed medium wave broadcasting in a limited area and an ordinary medium wave broadcasting in the vicinity of the limited area by providing a means which suppresses the intensity of a leaking electric field to an induction line installed in the area near and outside the limited area. CONSTITUTION:An induction line 7 which has the most intense electric field inside a tunnel (limited area) 2, cause interference to a house 9, etc., adjacent to a road 1 in the vicinity of the opening of the tunnel 2, and is installed in the vicinity of an impedance matching box is substituted by a leakage coaxial cable (suppressing means) 12. Then a slit 13 provided to the cable 12 is appropriately adjusted so that an electric field intensity at which a vehicle 3 can receive medium wave radio information inside the tunnel 2 without causing any interference to the house 9, etc., can be outputted in the vicinity of the opening of the tunnel 2. Therefore, occurrence of interference of a medium wave broadcasting at the house 9, etc., in the vicinity of the opening of the tunnel 2 can be eliminated easily and certainly.