User's Manual

8 Installing the low power base station
Connecting the GPS unit to the base station
This section provides you with GPS equipment mounting tips. It also explains how to
connect the GPS to the LPB and how to daisy chain other base stations in the cell so that they
can receive GPS information.
Most Expedience system deployments use multiple base stations, at multiple cell sites. As
such, these service providers must use a global positioning system (GPS) device to set the
date on the LPBs.
If you are using multiple base stations at multiple cell sites, you need one GPS device per cell.
You then directly connect one base station within that cell to the GPS device. Next, the other
base stations are connected to each other, using a daisy chain wiring scheme, so that all base
stations in the cell can receive a GPS signal.
You can choose the length of the cable that connects the base station to the GPS receiver.
Note: If you are not deploying multiple base stations at multiple cell sites, you can set up one
LPB to provide a time signal to the other base stations in the cell site. For more information
about how to configure an LPB to supply a time pulse to other LPBs in a cell, refer to the
NNOS User’s Guide.
GPS equipment mounting tips
You must use the NextNet Wireless supplied GPS system to supply a time synchronization
signal to the base stations in a cell. You cannot use a GPS from another manufacturer.
The GPS does not ship with mounting accessories. You can obtain these accessories from
many suppliers around the world, especially distributors of marine products.
Follow these tips when mounting the GPS:
• Mount the GPS unit on a threaded pipe or pole.
• The GPS mounting socket accepts a 1.0000 x 14 straight thread. It is recommended that
the pole/pipe you use be 1.000 inch.
• Secure the pipe or pole to the building or other support structure.
• Ensure at least half of the sky is clearly visible to the unit.
• Expose the unit to the southern portion of the sky. GPS satellites move generally from the
southwest to the northeast.
15 -422DATA
16 +19.5 V
17 GPS_V+
18 +422DATA
Table 1 Wiring diagram for LPB connector
Pin number Purpose