User's Manual

RTK Base Station Setup
Continued on next page SH20560,000011D 1908DEC093/4
The ability to use a single base station is a substantial
reduction in cost and maintenance. The drawback to this
method is that only one radio can be configured at a time.
A single RS232 port is used by the StarFire™ receiver
to communicate with an RTK radio. Two radios can
simultaneously receive RTK corrections from the receiver.
Unfortunately, the receiver can not process simultaneous
messages sent from the radios. The two radios send
different messages and interfere. To ensure that this
interference does not occur, the dual radio harness has
the radio send wire in only one branch.
To prevent network connection errors, a specific
procedure must be followed when configuring a base
station supporting two radios:
1. Connect the Dual Radio Harness to the StarFire™
Receiver.
2. Power the base station StarFire™ Receiver with only
900 MHz connected to 4wire Deutsch connector. The
receiver must have clear view of the sky.
3. Once the receiver determines its position, configure
900 MHz radio Network ID and Radio Channel.
4. Power down the base station StarFire™ Receiver.
5. Disconnect 900 MHz radio and then connect 450 MHz
radio to the 4wire Deutsch connector.
6. Once the receiver determines its position and
recognizes the radio, configure 450 MHz radio to
comply with the site license.
7. Power down the receiver.
8. With 450 MHz radio still attached to the 4Wire
Deutsch connector, connect the 900 MHz radio to the
3wire Deutsch connector.
9. Power the base station.
IMPORTANT: Do not attempt to change the radio
parameters while both radios are attached.
This can corrupt the configuration of 900 MHz
radio and may cause problems with rovers
liking to it. If this does occur, reconfigure the
radios with the process given above.
During normal operation, ensure that 450 MHz
radio is connected to the 4wire connector
and that 900 MHz radio is connected to the
3wire connector. If the receiver detects a
900 MHz radio, 450 MHz radio link may be
compromised. At its lowest data speed, the
450 MHz radio does not have the capacity to
transmit corrections at the 900 MHz radio rate.
PUPC000007 —UN—03DEC09
4Wire RTK Connector
PUPC000008 —UN—03DEC09
3Wire RTK connector
Vehicles using 900 MHz will see fewer messages
received when using a dual radio base station as their
correction source. The mandatory narrow bandwidth of
the licensed band radio results in a slower overtheair
baud rate. 450 MHz RTK uses the same message rates
for most configurations. However, the message rate had
to be reduced for the default narrowband settings to 2
messages per second.
Bandwidth (kHz) GFSK
Modulation
Data Rate (bps) RTK Correc
tions/second
25 L4 38,400
5
25 L2 19,200
5
12.5 L4 19,200
5
12.5 L2 9,600 2
158
121509
PN=18