Tandy Corporation

Norris M Clubb

A tunable capacitive coupling to a monopole antenna is provided which integrates the tuning mechanism into the supporting structure for the antenna. The base of the antenna is insulated from and supported by a cylindrical clamping assembly such as a metal compression ferrule in cooperation with an adjustment collar. This clamping mechanism enables the ferrule to be tightened like a drill bit in a chuck at any position along the base of the antenna. The coupling capacitance formed between the antenna radiator and the compression ferrule is proportional to the insertion depth of the antenna into the compression ferrule, thereby enabling the antenna to be tuned. The coupling method of the present invention enables repeatable tuning of the antenna either upward or downward in frequency within the band of frequencies accommodated by the particular antenna. The invention works especially well with so-called fiberglass antennas but is adaptable to metal elements having a lumped inductance and suitable insulation around the end of the antenna supported in the clamping assembly.

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Asheville, NC, United States of America

Norris M Clubb