Abstract: An antenna for receiving AM and FM radio frequency transmissions and for receiving and transmitting CB radio transmissions. The antenna includes a base, a generally elongate lower antenna section, and a generally elongate upper antenna section. The base is adapted to be mounted on an automobile and connected to the body of the automobile and to the outer conductor of a conventional automobile radio coaxial cable. The lower antenna section is attached to and extends above the base but is insulated therefrom. The electrical length of the lower section is selected to maximize reception of FM radio transmissions, the electrical length and the axial length of the lower section being substantially the same. The lower section is adapted to be connected to the inner conductor of the coaxial cable. The upper antenna section extends above the upper end of the lower section and includes a concealed loading coil electrically connected to the lower section.

Abstract: A radio-frequency coupler comprising a first terminal for interconnection with a conventional automobile receiving antenna used for receiving rf transmissions within a first radio-frequency band, a second terminal for interconnection with a receiver operating within the first radio-frequency band and a third terminal for interconnection with a transceiver operating within a second frequency band different from the first band. A first rf transmission path extends between the first terminal and the second terminal and a second rf transmission path extends between the first terminal and the third terminal. A first resonant circuit is connected in the first rf transmission path and tuned to pass rf transmissions in the first band but substantially block those in the second band.