摘要:
A combined AM/FM/cellular telephone antenna system comprises a coaxial cable with an upper portion of the inner conductor of the coaxial cable and an adjacent section of the coaxial cable together forming a cellular telephone dipole antenna. The coaxial cable forms a transmission line connecting the cellular dipole antenna to cellular telephone equipment. The outer conductor of a portion of the coaxial cable below the cellular dipole antenna serves as the AM/FM antenna. The combined antenna is encaged in a fiberglass housing and mounted on a metallic base having an upper shell and a lower shell. The upper shell is electrically connected to the outer conductor of the coaxial cable forming the antenna and the lower shell is connected to a ground plane. A coaxial cable having a center conductor connected to the upper shell and an outer conductor connected to the lower shield provides connection to AM/FM receiver equipment. Another coaxial cable having a center conductor connected to the center conductor of the antenna and an outer conductor connected to the lower shell provides connection to cellular telephone apparatus. A dielectric between the upper and lower shells provides a capacitance with low impedance in the cellular telephone frequency range and a high impedance in the AM/FM frequency range.
摘要:
A multiplexer circuit for CB, AM/FM, and television splits the radio and television signals, adding impedance to the split lines, and providing an amplifier upstream of the split.