User's Manual

SPSx50 Modular GPS Receiver User Guide 47

Setting up the Receiver 5

The SPS770 receiver does not have an internal transmit radio. To broadcast

corrections, connect the receiver Lemo port (Port 3) to an external transmit radio or a

cellphone.

The SPS770 receiver supports the following Trimble base radios:

• TRIMMARK 3

• Trimble SNB900

• Trimble PDL450

• Trimble HPB450

The receiver also supports third-party transparent radios and third-party cellular

modems.

To use an external radio with the SPS770 receiver, you need an external power source

for the radio—except for the SNB900. The SNB900 radio contains an internal battery.

Use the external radio’s configuration program, or display and keypad, to configure the

radio modem separately.

For more information, see Chapters 5 and 7, along with the SCS900 User Guide

Common ways to set up a base station

The following sections describe how to set up a base station in different ways

depending on the application, coverage area, degree of permanence versus mobility,

and available infrastructure.

Setting up a base station for permanent or semi-permanent installation

For construction applications, where machine and site positioning operations using

GPS will be carried out over a long time (weeks, months, or years), ensure that you

carefully choose the base station location.

The degree of permanence of the setup increases with the expected duration of

operational requirements. The more assets that use the base station as a source of

corrections, increases the cost of any base station downtime, and increases the

requirements for a permanent base station setup. Providing a semi-permanent or

permanent setup can also reduce potential sources of error over time caused by

repeated daily setup and the potential to put the GPS antenna in the wrong place (that

is, not at the original location).

On the largest and longest operational jobsites, the permanent or semi-permanent

installation is the most common solution. In these cases it is most common to find the

SPSx50 Modular GPS receiver or the SPS770 Modular GPS receiver used as the base

station. In these installations, the GPS receiver is located typically in a site office or

trailer where it is easy to access to check or configure, and where it is secure from theft