| 主权项 |
1. A frequency adjustable antenna for radio transceivers operable over a range of radio frequencies comprising;
a. a lower electrically conductive base mast section with a radio frequency connection thereto, b. an elongated hollow cylindrical housing made of an electrically non-conductive material and having formed in an inner cylindrical wall surface thereof a longitudinally disposed helical groove, c. an electrically conductive loading coil comprised of a conductor formed into longitudinally spaced apart convolutions comprising a helix of the same pitch as said helical groove in said housing, and fitting within said helical groove with an inner cylindrical surface of said helix located radially inward of said inner cylindrical wall surface of said housing, each of said coil convolutions having a radially inwardly located arcuately curved convex surface, d. a base plug located at a lower end of said housing, sad base plug being in electrically conductive contact at a lower end thereof with said mast section and at an upper end thereof with a lower end of said coil, e. a cap adapted to hold in electrical contact therewith an elongated conductive whip located at an upper end of said housing, said cap being in electrical conductive contact with an upper end of said coil, f. an elongated conductive coil contactor support shaft located coaxially within said mast and said coil, g. a coil contactor carried by and in electrically conductive contact with said conductive shaft, said coil contactor including a transversely disposed disk which has extending radially inwardly into a longitudinally disposed outer peripheral circumferential wall thereof at least at first pair of circumferentially spaced apart, radially disposed cavities, each of said cavities holding a radially movable electrically conductive contactor ball which is urged radially outwards by a compressed electrically conductive helical compression spring located within a said cavity between a said contactor ball and a transverse inner end of said cavity with sufficient force to maintain continuous rolling electrically conductively contact between a radially outwardly located surface of a said contactor ball a radially inwardly located arcuately curved convex surface of at least one of said coil convolutions when said coil contactor disk is moved longitudinally within the bore of said loading coil, said contactor balls having a diameter larger than longitudinal spacing between said convutions of said loading coil, said compression spring, contactor balls, and said convolutions of said loading coil each having an electrical conductivity at least as great as that of brass, h. at least a first RF de-coupler ring which is located in said electrically conductive cylindrical base plug, said RF de-coupler ring bearing resiliently and slidably against the outer cylindrical wall surface of said shaft longitudinally slidably located within a bore through said base plug, and I. an actuator for moving said conductive shaft and said coil contactor disk coaxially located within said bore of said loading coil longitudinally upward and downward to short out more or less coil turns in series with said whip and said mast, thereby decreasing or decreasing the inductance between said whip and said mast section to adjustably tune said antenna to higher or lower frequencies. |
