Extendable rod antenna and helical antenna with frequency adjusting conductor

An antenna assembly comprising:

• a rod antenna unit composed of a primary antenna formed by a rod antenna element, an insulating cover covering said primary antenna at least at its lower end portion, and a connector terminal secured to said lower end portion of said primary antenna, said primary antenna, said insulating cover and said connector terminal being axially aligned;
• feeding metal pipe fitted in a top of a radio housing, and having a centrally-disposed through hole for slidably receiving said rod antenna unit between its extended and retracted positions, and contact springs for elastically contacting an outer peripheral surface of said rod antenna unit;
• a secondary antenna formed by a helical antenna element and fixed at its lower end to said feeding metal pipe, characterized in that when said rod antenna unit is retracted in said radio housing, said contact springs contact said insulating cover around said rod antenna unit, cutting off electrical connections between said feeding metal pipe and said primary antenna;
• and also characterized in that when said rod antenna unit is drawn out of said radio housing to said extended position, said contact springs electrically contact said connector terminal of said rod antenna unit, electrically connecting said primary antenna and said secondary antenna to said feeding metal pipe;
• and
• a frequency adjusting conductor, wherein said frequency adjusting conductor is wrapped around said insulating cover for contact with said contact springs to adjust a receiving frequency of said secondary antenna when said rod antenna unit is retracted into said radio housing.