Thales Z-Max Operation And Application Manual page 188

UHF Radios
The Z-Max uses data links that operate in the UHF frequency range. UHF radios
can communicate over long distances. Actual radio range depends on factors
including the transmitter power, the height of the transmitting antenna, the
topology over the transmission path and rover sensitivity. Although UHF radios
are affected by line-of-sight obstructions between the base and rover systems,
the increased transmission power of these radios allow for transmissions to push
through more obstructions than other radios functioning at higher frequencies (for
example, spread spectrum radios). Because of the power levels at which these
radios function and the frequency they utilize, a license is often required. In the
United States, a license must be obtained from the FCC to operate UHF radios.
Check the local radio transmission regulations in your region.
Because the base radio is a powerful transmitter and the remote radio is a
receiver, the hardware required for each is quite different. The Z-Max RTK system
uses UHF data links which look and function differently at the base and rover.
Because the base radio needs to send data over long distance, it has a sizeable
transmitter that is too large to fit into the Communication Module housing. It
consumes much more power than the Z-Max and generally requires its own
dedicated power supply. The base radio is an external device that is connected to
the GPS Receiver Module serial port and is powered by a separate power supply
The remote radio is part of the Z-Max Communication Module. The
Communication Module connects directly to the GPS Receiver Module and since
the rover radio receiver uses comparatively little power to operate, the
Communication Module uses the GPS Receiver Module's power supply. The
antenna for all UHF devices is the Vortex UHF Antenna Module which is
described on page 169.
Thales U-Link Radio
The Thales Navigation U-Link radio, Figure 2.6, is a high performance device
designed specifically for GPS RTK systems. It provides long range, low power
consumption and high data quality. The U-Link rover is housed in the Z-Max
Communication Module. The base transmitter is connected to the Z-Max with
a cable that provides data and power for transmission. Base and rover radio
channels can be changed through the Z-Max Front Panel User Interface or
through application software running on a handheld computer.
System Components 165