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BMW - Other Models
All other, newer BMWs have the in-glass electronic systems by Fuba. The following information
applies to these cars as follows:
- All 8 series
- 1988 up 7 series
- 1989 up 5 series
- 1992 up 3 series
- All/most future BMWs without any visible aerial. (Antenna in the
wind)
These cars have 2 or 3 antennas in the rear glass, including one
which is the defroster wires, all embedded or printed on the inside of the
glass. The usual configuration is a small computer/antenna selector/signal
amplifier in the left side C-pillar. This small box can be accessed by
removing rear seats completely then removing large plastic trim panel.
The "box" gets a signal from the radio via a thin (aprox
1/8") coaxial cable. This is an IF (Intermediate Frequency) signal
out of the radio. My best guess is that it comes as a variable voltage
level not a data signal. The computer uses this information from the radio
to learn how strong the reception is at a given instant. As usual for a
computer, antenna or antennas are selected at maybe 30 or 60 times per
second. It is possible for the computer to select 1 single antenna or
combine 2 and maybe 3.
If the original BMW radio is replaced with an aftermarket radio, the
computer defaults to one antenna, probably the largest array. The
reception quality will become fairly poor using a single antenna in the
rear glass. The best solution apart from re-installing the original radio
is to install a single antenna in the rear fender, the old fashioned, old
reliable way. Otherwise an aftermarket radio with 2 antenna inputs
(diversity system) would be a near remedy: In this case use the default
antenna in the rear glass plus an aftermarket small electronic antenna
inside the front glass.
Small electronic stick-on antennas like our AW-276E can work quite well when used in conjunction with another antenna. Antenna World has an Italian-made unit with 2 flexible blades either side of the small module. This antenna is ideal to mount behind the rear-view mirror, top center inside windshield.
Note: No reception on the AM band means the power is somehow
disconnected from the antenna box in the C-pillar. Check for voltage at
the box itself. Many times when installing an aftermarket radio the power
lead to the antenna box is left disconnected. It should go to the
power-antenna lead, (blue or green) of the aftermarket radio.
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More information will be added here as it becomes available and comfirmed. The information contained here is not guaranteed and should be used at your own risk although effort and experience show it to be good there may be errors and the writer nor this company can assume any liability arising. Antenna warranties stated are for parts and complete antennas and do not include incidental costs such as labor and other expenses to send the antenna in for warranty work or replacement. We welcome your input and comments.
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