Volvo Trucks North America, Inc. Date Group No. Page
Service Bulletin 4.2004 392 08 7(47)
Signal Disruption
W3003001
Since the higher frequency signals behave more like
light, the signal may be reflected or there may be areas
of shadow. When a receiver has more than one signal
due to reflection, we call it multipath distortion. When a
receiver is located in a signal shadow, we call it flutter.
Multipath
This condition is caused by reflected signals. The
reflected signal must travel further than the direct signal,
so it takes longer to get to the antenna and it is weaker
when it gets there. The receiver then has two signals
which are slightly out-of-time with each other. The two
signals tend to cancel each other out. This condition is
most common in built-up areas which reflect the signals.
A multipath area is often only a few inches wide. At home
you can locate the antenna to avoid a multipath area, but
in your vehicle you may drive in and out of multipath areas.
Flutter
Flutter occurs when the signal strength is too low to allow
proper reception. Flutter can occur when in a fringe area
of a transmitter. Flutter can occur much closer to the
transmitter if the receiver is located in a signal shadow.
In a strong signal area, reflection will generally fill in
the reception shadows. When there is little to support
reflection, an obstacle may cause a signal shadow.
Operating in the shadow will cause flutter. This may also
be called “picket fencing”.
To Next Page
Loading...
Need help?
General
