User's Manual

DRAFT TrimTrac Locator Technical Manual 40
Make sure that the TrimTrac locator is reasonably positioned to receive GPS
signals.
Location
The TrimTrac locator should be installed as close as possible to horizontal plane,
preferably with a reasonably clear view of the horizon and sky. If something on
the vehicle—for example, the air conditioning unit on a cab or the trailer
connected to a tractor—blocks a significant portion of the horizon and the GPS
signals, the GPS receiver will take longer to acquire enough satellites for a
position fix. If the TrimTrac locator frequently times out before completing a
position fix, try moving the TrimTrac locator to a new location where it is not
blocked as much.
GPS Jamming
The TrimTrac locator should be installed as far away as possible from
transmitting antennas, including satellite communication, radar, VHF and cellular.
These transmitters may emit jamming signals that interfere with the GPS
receiver’s ability to track GPS satellite signals. Generally, the stronger the other
transmitting device, the wider the distance required between antennas. For the
TrimTrac locator, Trimble recommends a minimum clearance of 46 cm
(approximately 18 in.) from these transmitting devices.
Land-based transmitters, including microwave and television transmitters, can
also interfere with GPS reception. If the TrimTrac locator is operating near an
antenna farm, the TrimTrac locator may temporarily lose GPS reception while in
the vicinity of the transmitters. Reception should return once the TrimTrac locator
moves away from the transmitters. If your GPS signals are being jammed and
moving does not correct the situation, the source of the jamming signal may be
another antenna mounted too close to your TrimTrac locator. If possible, turn off
the equipment using other nearby antennas to see if this corrects the problem. If
turning off nearby equipment un-jams your GPS signals, you need to relocate one
or more of the jamming antennas.
Poor GSM Coverage
Check to make sure the SIM is not missing or incorrectly installed, or the PIN
number configured in the TrimTrac does not match the PIN in the SIM. Do the
following:
1. Insert a SIM is none is present.
2. Remove and reinsert the existing SIM to verify proper installation.
3. Check the TrimTrac locator configuration to ensure the correct PIN is
programmed.