User's Manual

4 Setup Guidelines
34 SPSx50 Modular GPS Receiver User Guide
Cellular phone towers can interfere with the base station radio broadcast and
can stop corrections from reaching the rover receiver. High-power signals from a
nearby radio or radar transmitter can overwhelm the receiver circuits. This does
not harm the receiver, but can prevent the receiver electronics from functioning
correctly.
Low-power transmitters, such as those in cellular phones and two-way radios,
do not interfere with receiver operations.
• Do not set up the base station directly beneath or close to overhead power lines
or electrical generation facilities. The electromagnetic fields associated with
these utilities can interfere with GPS receiver operation. Other sources of
electromagnetic interference include:
– Gasoline engines (spark plugs)
– Televisions and computer monitors
– Alternators and generators
– Electric motors
–Equipment with DC-to-AC converters
– Fluorescent lights
–Switching power supplies
• Place the GPS receivers in a protected and secure location. If the base station is
in the center of a jobsite where heavy machinery is operating, place flags around
the base station to warn operators of its existence.
• If you place the SPSx50 Modular GPS receiver or SPS770 GPS receiver in a lock
box on the jobsite to protect the receiver from theft or from the weather, shield
the lock box from direct sunlight and provide ventilation for the receiver
through an inlet and extractor fan. A receiver that has a broadcast radio
generates significant heat. Do not allow the temperature in the box to exceed
65 ºC (149 ºF).
If working in a cold climate, you may need to provide heat to the receiver. Do not
operate the receiver below –40 ºC (–40 ºF).
• Trimble recommends that, wherever possible, you keep GPS receiver equipment
dry. The receivers are designed to withstand wet weather, but keeping them dry
prolongs their life and reduces the effects of corrosion on ports and connectors.
If the equipment gets wet, dry the equipment with a clean dry cloth, and leave
the equipment open to the air to dry. Do not lock wet equipment in a transport
case for prolonged periods. Avoid exposing the GPS receiver to corrosive liquids
and salt water wherever possible.