Roof antenna module, component description - GF82.62-P-3127GZJ

MODEL 164.1/8 with CODE (498) Japan version up to Model Year 2008

Fig 1: Identifying Roof Antenna Module

Courtesy of MERCEDES-BENZ USA

Location

The roof antenna module is installed in the rear area beneath the headliner.

Fig 2: Identifying Roof Antenna Module Components

Courtesy of MERCEDES-BENZ USA

Function

Antenna amplifier

The antenna amplifier in the roof antenna module is configured depending on the national version. It receives:

AM, FM
Radio remote control central locking (FZV)
GPS
Telephony

The antenna amplifier in the roof antenna module is supplemented by the FM rear window antenna amplifier (A2/19), a dual FM amplifier for the FM2 antenna and the FM3 antenna. The amplifier is directly connected to the antenna amplifier in the roof antenna module via a coaxial cable.

Antenna FM/AM/RRCL [FZV]

The FM/AM/RRCL antenna is designed as a wire antenna in the roof antenna module and is connected directly to the antenna amplifier.

AM reception:
Filters and amplifies AM frequencies (medium wave only, also with traffic information) for radio reception
FM reception:
Filters and amplifies FM frequencies for radio reception.
RRCL reception:
An amplifier is additionally installed in the roof antenna module for the RRCL [FZV] signals. The RRCL signals are demodulated and transferred directly to the rear SAM control unit (N10/8).

Antenna diversity feature (FM)

The diversity feature serves for reduction of reception interference. The diversity feature integrated into the roof antenna module serves for switching over between the FM antennas (FM1 to FM3) in order to allow the best possible reception.

MODEL 164.1/8 with CODE (498) Japan version up to Model Year 2008 At first, the audio gateway control unit (N93/1) receives the FM signal of the active antenna from the roof antenna module. The audio gateway control unit uses the incoming FM signals to generate the IR reference signal. The reference signal is transmitted to the roof

The diversity feature checks whether the IR signal is free of interference after demodulation. If interference is present, the system automatically switches over to the next of the four FM antennas.