In contrast to a home radio, a car radio is constantly subjected to changing reception conditions. At one point reception is excellent, however, reception may be very poor after just a short distance has been covered. Reception can be best checked by driving in a circle. In this way, the antenna is pointed in all directions.
An antenna each for the AM (amplitude modulation) and FM (frequency modulation) bands is integrated in the rear window. The received signal is amplified by the antenna amplifier and is transferred via a high frequency line (HF line) directly into the radio.
In the antenna diversity option, one antenna is connected for the AM band and three separate antennas for the FM range. The three FM signals received are switched in the diversity amplifier through to the radio cyclically via the RF line. The radio sends a feedback signal relating to the quality of the received antenna signal (the intermediate frequency signal) to the antenna diversity system. The antenna diversity system decides which of the three antennas has the best reception quality at present and switches this antenna through to the radio until the next measuring cycle is carried out. The antenna (FM1) arranged vertically in the rear window is used in the case of interference in the intermediate frequency signal.
The antenna (aerial) system on the Z8/E52 is integrated in the rear bumper with the antenna amplifier located in the luggage compartment. The antenna structure in the rear bumper consists of an AM section (amplitude-modulated) and an FM section (frequency-modulated). The AM section of the antenna consists of a line that is insulated on one end and is equipped with a blade terminal on the other end to facilitate connection to the antenna amplifier. The FM section of the antenna consists of two lines that are connected by a coaxial cable. The coaxial cable is secured to two blocks that are screwed into the bumper and are connected to vehicle ground. Care must be taken to ensure that the aluminium moulding of the bumper is connected to the vehicle ground (earth).
Operation of the antenna must not be impaired by other add-on parts such as lights, reversing sensors or similar.