LMU-2x20™ Hardware and Installation Guide
V1.0.10
December 12, 2010
Copyright ©CalAmp DataCom Inc 2010
- 35 -
CalAmp Proprietary & Confidential
prevent the GPS receiver from operating properly. When laying out the antenna cable, care
should be taken so that the cable is not subjected to crushing or strain.
4.2.2.3
Placement of Combination and Internal Antennas
When dealing with combination antennas, it is more important to considered GPS
performance over Comm performance. GPS signal strengths are much lower than those
typically seen by cellular networks supported by the LMU. In order to maximize the
performance the LMU should have a clear view of the sky as possible. When installing the
GPS antenna in a vehicle, make sure that there are as few obstructions as possible close to
the LMU that might block the view 360
°
to the horizon. As with stand-alone GPS antennas,
nothing should not block the combination antenna beyond 5
°
above the horizon with the
best location being near the center of the roof. For more covert installs, directly under the
front or rear-windshields are also acceptable.
15 Examples of Good (Green), OK(Yellow) and Poor(Red) combo antenna placements
16 Examples OK(Yellow) and Poor(Red) internal antenna placements
