User's Manual

6-75
Use the GPS-to-base station cable to attach the GPS unit to one of the base stations in the
cell.
To connect the cable to the GPS unit and to the base station (both of which have already
been installed and mounted):
1 Connect the cable’s molded, circular female connector to the GPS unit.
2 After connecting the cable to the GPS unit, run the cable to the base station. Plug the
cable’s other end into the base station’s GPS connector.
3 Secure the cable that you just ran to an appropriate support structure. Coil and tie any
excess cable.
4 The GPS unit receives its power from the base station. The base station supplies power to
the GPS device, which uses 18 volts DC at 150 milliamperes.
5 So that the remaining base stations in the cell can receive a GPS signal, connect a base
station adjacent to the base station you just connected to the GPS unit. For more
information about cables that you can use, refer to Table 6.5.
Continue to use the daisy chain wiring scheme to connect the remaining base stations, until
all of the base stations within the cell are connected to each other.
On the last base station in the daisy chain, connect the load termination on the open GPS
connection.
Connecting to the backbone network
The base station connects to a TVS module. You then connect the TVS module to your
network. Typically, base stations connect to a level 2 switch at the cell site, using a 10BaseT
connection. The switch controls the base station data traffic to and from the backbone
network.
Connect the switch to the backhaul network using the appropriate cabling.
Grounding base stations
The grounding location differs depending on the type of base station you are using.
• Base stations with the ability to change their modulation method (AMOD base stations)
have a ground lug located at the top right corner.
• Base stations without the ability to change their modulation method have a grounding
connection at the base of the antenna connection.
To ground either type of base station, run a 6-gauge or larger grounding wire from this
connection to the ground bar on the rack, to the building’s ground connection on the roof, or
to the grounding location at the tower.
The ground to which you connect the base station should be 6 ohms or less to ground.
The 48 volt power input to the base station is floating, so either the positive or negative can
be grounded.
Powering base stations
This section describes tips for powering base stations, as well as the component connection
sequence you need to use to properly power base stations.