User's Manual

5 Setting up the Receiver
48 SPSx50 Modular GPS Receiver User Guide
and the weather. The GPS and radio antennas are normally mounted on a permanent
structure on the roof of the building, where they are high and clear from obstructions
and where the radio antenna can provide the maximum range of operation.
The GPS antenna used is most commonly the Zephyr Geodetic – Model 2 antenna,
which has a large ground plane that eliminates multipath, providing the best GPS
performance at the base location. The antennas are connected to the receiver by high
quality RF cables.
The receiver is connected to a permanent power supply (mains or generator power).
The internal battery of the receiver is always being charged, and acts as an
uninterruptible power supply if there is a power outage. In some cases, the receiver
may also be connected by an Ethernet cable to the Internet, so that it can be
monitored and configured from a remote location, and warn an administrator by
e-mail or text message if there is a change to the configuration. In these situations, the
receiver can transmit GPS RTK corrections to a remote radio or receiver over the
Internet for rebroadcast requirements without using repeaters.
Figure 5.1 SPSx50 receiver permanent installation
Setting up a Base Station for Daily Site Use: T-Bar
For construction applications where a daily setup and takedown of equipment is
required for security reasons, Trimble recommends that you use a T-Bar setup.
The T-Bar consists of a post mounted in concrete (so it cannot move), which has a
solid metal Bar T piece mounted to it to provide lateral separation between the GPS
antenna and radio antenna. The T piece of the T-Bar will have vertical rods at either
end, terminating in a 5/8 thread to which the antennas can be mounted. Trimble