Abstract: An adjustable mobile antenna comprising a dielectric rod several feet in length, a loading coil comprising a conductive wire helically wound in close fashion along an upper portion of the length of the dielectric rod, a protective outer insulator jacket covering the loading coil and a major portion of the dielectric rod, and a dielectric sleeve mounted on the outside of the protective jacket and slidable thereon along the length of the loading coil to effect "dielectric loading" of the loading coil to control the frequency of the antenna.

Abstract: An adjustable mobile antenna comprising an upper metal mast and a lower metal mast, the upper mast being telescopically received in the lower mast and adjustably movable longitudinally therein to vary the length of the antenna and thereby effect tuning thereof, a clamping member for releasably locking the upper mast in a selected position relative to the lower mast, a dielectric rod extending upwardly from the upper end of the upper metal mast, and a loading coil helically wound on the dielectric rod with a lower end of the coil connected to the upper metal mast adjacent the upper end thereof, and a protective outer jacket covering the loading coil, the antenna being tunable by simply adjusting its length.