Antenna

TV Reception

To ensure TV reception, even under changing reception conditions, two antennas are used to receive the TV signals. In Drive variant with rear-compartment monitor, the digital video module has a third antenna to ensure reception while the vehicle is being driven.

Brief description of components

Rear window antennas
The rear window incorporates an antenna on both the left and right sides. An assignment of "antenna left / antenna right" to "antenna 1 / antenna 2" is not possible at the control-module input.

Antenna amplifiers
To amplify the received TV signals, separate amplifiers are installed for the antennas. The amplifiers are supplied with power by the video module via the HF line.

Video module
The amplified HF signals are applied at separate inputs to the video module. The signals are conditioned according to their subsequent use in the video module. The video module monitors current, voltage and field strength of the antennas connected to an input.

Main functions

Antenna recognition
The analog video module recognizes antenna 1 and antenna 2 with the aid of the diversity function. However, because the antenna connectors are not coded, it is not possible to recognize which is the left or right antenna.

The digital video module recognizes antenna 1, antenna 2 and on the Drive variant antenna 3. The numbering of the antennas runs from the center of the module consecutively towards the outside - antenna 1, antennal 2 and on the Drive variant antenna 3.

For fault localization, a signal path must be checked in accordance with the schematic. For this purposes, a channel with TV signal must be adjusted before the check.

Service notes for the analog video module
The right amplifier operates perfectly with a power consumption of 60 mA. The field strength can be read out as a current value.







If the field strength is significantly lower than before once the antenna has been disconnected, this antenna path is O.K.

Service notes for the video module with digital reception
The video module for digital reception provides the possibility to read out the antenna currents of each individual antenna as a value. There is the same possibility for the field strength.