| 摘要 |
PURPOSE:To use properly a whip antenna and a helical antenna and to attain the same effect from both the antennas by integrating the whip antenna and the helical antenna so as to have only to expand/contract the unified antenna when the whip antenna and the helical antenna are properly used. CONSTITUTION:An earth antenna composed of a whip antenna element 4 being a 3/8 wavelength rod conductor wire using the casing I of a radio equipment is used for an earthing body and formed as the antenna of an upper stage, a matching coil 7 is provided on the base part of the element 4 and the coil 7 is energized through a feeding coaxial line 9. A helical antenna composed of a 1/2 wavelength helical antenna element 5 is used for an antenna at a lower stage and the antenna is structured so as not to be in electric continuity to any part and the helical antenna is coupled with the whip antenna element through a capacitance from the base part of the antenna. When the whip antenna is expanded, the antenna acts like a 3/8 wavelength antenna and when the antenna is contracted, the antenna acts like a reduced 1/2 wavelength helical antenna, then the switching of the antenna is simplified and the VSWR and the gain excellent at all times are obtained.
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