| 摘要 |
PROBLEM TO BE SOLVED: To provide an extensible bottom helical antenna having a long effective length as a whip antenna, in spite of a short accommodating length within a radio equipment cabinet. SOLUTION: An antenna knob at the tip of a whip antenna is made of conductive material, and a cylindrical conductive operation element is provided, while a joint of non-conductive material separates the antenna knob and the whip element electrically. The lower end of the antenna knob, the joint, and the upper end of the whip element are covered by the operation element at the time of antenna expansion, both are electrically combined by the conductivity of the operation element, and the whole is operated as an antenna element. At the time of antenna accommodation, the operation element is moved to the upper end of the whip antenna, and the joint separates the antenna knob and the whip element electrically, and electric power is not supplied at whip element. COPYRIGHT: (C)2006,JPO&NCIPI
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