Apparatus for isolating from ground and exciting a conductive tower for use as a vertical antenna
OwnerRalph O. Robinsoninventor
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Abstract
A method and preferred apparatus for introducing radio frequency isolation near the base of a conductive tower to prevent significant flow of RF current into the ground, thereby to produce an elevated vertical antenna. The invention further relates to a method and apparatus for introducing RF power into the upper portion of the isolated tower to cause said portion to radiate or receive at desired frequencies. Isolation and "excitation" are accomplished by the placement of tuned shortened quarter wave conductive sections along selected portions of the tower, the quarter wave sections used for antenna excitation being also used for impedance transformation to match a coaxial transmission line of nominal inmpedance.
Claims11
An antenna in the form of an elongated conductive supporting tower one end of which effectively joins to ground, said tower having isolator means including at least one tunable electrically shortened quarter wave length parallel transmission line section attached to at least one portion of the tower for providing a high impedance at said portion to current at the resonant frequancy thereof, the tower further having exciter means having at least one tunable electrically shortened quarter wavelength parallel transmission line section attached to at least a second portion of the tower for exciting said second portion to cause radiation or reception at a selected frequency, said isolator means and said exciter means both being substantially coincident with and parallel to said antenna.
Dependencies are inferred from the claim text.