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.
Examples of Good (Green), OK(Yellow) and Poor(Red) combo antenna placements
Examples OK(Yellow) and Poor(Red) internal antenna placements
5.2.3 Access to the SIM (Subscriber Identity Module) Card
When used in a GSM or iDEN network, each LMU uses a Subscriber Identity Module (SIM) card,
which should be inserted before you install the LMU for the first time. The SIM card is attached to the
main-board inside the housing of the LMU unit.
At some future time, you might need or want to replace the SIM card with a different one, so try to
install the LMU in such a way that the cover can be removed to make the SIM card accessible.
5.2.4 Protection from Heat
