| 摘要 |
A mobile high-frequency antenna rapidly adjustable to minimize VSWR and maximize transmitting and receiving efficiency includes a conductive whip mounted on a coil housing containing a solenoidal loading coil electrically connected at an upper end to the whip and at a lower end to a conductive mast which supports the coil housing. A coil contactor disk at the upper end of a conductive metal shaft raised or lowered by a stepper motor-driven lead screw has protruding spring loaded balls which rollingly contact inner surfaces of coil turns to thus insert less or more inductance between the shaft and whip to tune the antenna. A pair of RF de-couplers in a coil housing base plug which electrically contacts the mast and the lower end of the coil slidably support and electrically contact the shaft, thus shorting out lower parts of the coil to suppress harmonic currents from being induced therein. |
