Vehicle FM and TV broadcasting antenna system - combines phase shifted broadcast signals and selects signal for best reception using diversity control

摘要

The FM antenna system has main and auxiliary antennae (11,12) to receive an FM transmission and output main and auxiliary FM signal respectively. A variable phase shifter combines the output signals with a set phase shift between them. The FM system operates with diversity reception (16) in which it selects a signal from the combined signal which will be received well. The main and the auxiliary signals are combined with a phase difference such that the directional characteristics of the combined signal deviate from the component signals. The TV antenna system also has two antennae which receive the broadcast and output two TV signals. These are combined with a given phase difference. They are also combined with a second, different, phase difference. A diversity unit selects the combined signal allowing best reception and feeds this to a TV receiver. USE/ADVANTAGE - Glass mounted vehicle antenna. Good reception of signals coming from all directions, whether horizontally or vertically polarised, without requiring modification of antenna.