SETSUCHIGATAORIKAESHIANTENANOJIDOSEIGOSOCHI

摘要

PURPOSE:To attain stable antenna operation by providing a matching section changing the reactance between a grounded folded antenna and a transmitter and a control section controlling the matching section between them. CONSTITUTION:A coil 17 is provided additionally in a coil storage box 14 of an antenna top part in the grounded folded antenna comprising a supporter 11 and a sub-lead wire 13 and also the matching section 18 and the control section 19 controlling this matching section 18 are installed in a station building 15 so that the matching is attained always with the transmitter 20 at a higher efficiency of the antenna. Since the transmitter 20 is protected by providing the automatic matching device comprising the matching section 18 and the control section 19 between the folded antenna and the transmitter 20 in this way, the folded antenna is miniaturized and further, even if the grounding is incomplete, comparatively efficient and stable operation is attained.