Volvo 240 Owner's Manual page 30

Volvo 1990 240 Model
Operating instructions are contained in the manuals associated with each model.
These manuals are placed in the cars when the equipment is installed.
Your Volvo Dealer will be able to assist you with any questions regarding the operation of this
equipment.
Radio antenna mast
Note: Always lower the antenna mast when entering automatic car wash. Retractable antennas should
be cleaned and lubricated every 5,000 miles (8,000 km). On fixed (removable) mast antennas, be sure
to unscrew and remove the antenna before entering an automatic car wash or a garage with low
overhang.
The following information may help to explain differences between car radio reception and radio
reception in the home.
Signal sending
FM waves do not follow the earth's surface and do not bounce against the atmosphere as AM waves do.
Cross modulation
When receiving a weak signal in the vicinity of another, stronger signal, both stations may be received
simultaneously.
Weak reception (fading)
Because of the limited range of FM senders and the way FM waves spread, this problem usually occurs
with FM reception.
Mountains or similar obstacles can sometimes cause disturbances.
Multipath Distortion
FM Signals are typically "line-of-sight", and very reflective. Their reflectivity to objects such as
buildings, mountains, even other passing vehicles, causes the condition known as multipath distortion.
This distortion is the result of the reflected signal, and the direct signal reaching your antenna at slightly
different times causing a cancellation of all signals. This condition will sound like hissing, or static.
Very little can be done to eliminate this problem, however, lowering the treble on your radio could help
mask these disturbances thereby allowing you to achieve optimum pleasure from your audio system.
file:///K|/ownersdocs/1990/1990_240/90240_05.htm (5 of 6)12/30/2006 8:25:03 AM