Radio Interference - BMW 3-series convertible Complete Vehicle Workbook

Operating Mode Remark
FM1/AM
AM reception, diversity off
DIV
Diversity mode
AM/FM diagnosis, AM
Diagnostic mode
amplifier off
Diagnosis, FM antenna
Switching pulse
switching
Diagnosis output short circuit
Diagnostic result
proof, Us is switched across
not OK
200 Ohms to ground

Radio Interference

Check the following if radio interference is encountered:
• Station tuning
• Mechanical damage to antenna structure
• Supply voltage terminal Rad_On for antenna amplifiers in
diversity module
• Antenna connector at diversity module
• Ground connection of diversity module with mounting screws
• Antenna connector at radio or navigation system
The E93 supports the following concepts for minimizing interfer-
ence in the reception of AM and FM stations:
"Us" "Us" "Us"
min typical max
0.5 V due
----
0 V to ground
offset
1.5 V
2.5 V 3.5 V
4.0 V
5.0 V 6.5 V
7.5 V
8.5 V 14 V
0 V
0.5 V 2 V
E93 Complete Vehicle Workbook
33
• Ground connection of rear lid via read lid hinge with integrated
ground straps
• Ground connection of hinges on left and right of body
• Low-noise AM and FM antenna amplifiers with direct ground
screw connection