Ford 2007 Town Car Owner's Manual page 91

Entertainment Systems
Radio reception factors
There are certain factors that may effect your radio reception.
• Distance/strength. The further an FM signal travels, the weaker it is.
The listenable range of the average FM station is approximately 40 km
(24 miles). This range can be affected by "signal modulation." Signal
modulation is a process radio stations use to increase their
strength/volume relative to other stations.
• Terrain. Hills, mountains and tall buildings between your vehicle's
antenna and the radio station signal can cause FM reception problems.
Static can be caused on AM stations by power lines, electric fences,
traffic lights and thunderstorms. Moving away from an interfering
structure (out of its "shadow") returns your reception to normal.
• Station overload. Weak signals are sometimes captured by stronger
signals when you pass a broadcast tower. A stronger signal may
temporarily overtake a weaker signal and play while the weak station
frequency is displayed.
Principles of GPS (global positioning system) operation
Your system directs you based on information derived from global
positioning satellites, road maps stored on the DVD, sensors in your
vehicle and the desired destination. The system compiles all necessary
information to guide you to your selected destination. Space satellites
determine the vehicle's current location and transmit position and time
signals to your car.
If the vehicle has been parked for a long period of time, the navigation
function may be temporarily unresponsive. The navigation system will
operate reliably again once GPS reception is available for a few minutes.
Limited GPS reception
System performance may be adversely affected if GPS reception is
interrupted or interference occurs over a distance of several miles. The
following are possible causes for GPS reception being interrupted. If the
vehicle is:
• in multi-story parking garages
• in tunnels and under bridges
• inside or in between buildings
• by forests or tree-lined avenues
• in heavy rain showers and thunderstorms
• in valleys and in mountainous regions
90
2007 Town Car (tow)
Owners Guide (post-2002-fmt)
USA (fus)