TrimTrac ProE Locator, Technical Manual

Page: 89 / 233

TrimTrac ProE Locator Technical Manual v2.0e 71
ability to track GPS satellite signals. Generally, the stronger the other transmitting
device, the wider the distance required between antennas. For the TrimTrac ProE,
Trimble recommends a minimum clearance of 50cm (approximately 18 in.) from
these transmitting devices.
Land-based transmitters, including microwave and television transmitters, can
also interfere with GPS reception. If the TrimTrac ProE is operating near an
antenna farm, the TrimTrac ProE may temporarily lose GPS reception while in
the vicinity of the transmitters. Reception should return once the TrimTrac ProE
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 ProE. 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. Also, check
to confirm that you are using the correct SIM PIN as required by your SIM card
provider. Do the following:
1. Insert a SIM if none is present.
2. Remove and reinsert the existing SIM to verify proper installation.
3. Check the TrimTrac ProE configuration to ensure the correct PIN
is programmed.
4. Make sure that the SIM card hold-down latch is securely fasten
and all four corners are locked down.
Even in areas with strong GSM service, there may be pockets where GSM service
is poor or nonexistent due to how the carrier builds the network. Contact your
local service provider for information on GSM coverage.
How to Evaluate TrimTrac Placement
The number one rule in GPS is that a GPS antenna with a clear view of the sky
will have better performance than one that has a blocked view. For instance, a
TrimTrac ProE placed on the dashboard of a vehicle will almost certainly have
more GPS fixes than a unit placed under the seat or in the glove box, everything
else being equal. The real question is whether the TrimTrac ProE will provide the
level of performance required to meet the needs of the application.
The answer to this question is best derived from field-testing of the specific
vehicle and placement options. The test plan should call for at least one unit with
an external antenna that is placed on the roof of the vehicle. This antenna
placement will provide the best possible GPS performance and will establish the
baselined against which all other configurations and placements will be evaluated.
Operate all devices simultaneously. Do not attempt to place a single unit in one
location, do a test drive, and then relocate it to another area of interest. The only