Garmin GBR 21 - Manual (Page 20)

18
Reference
Troubleshooting
Chart
If the ‘No Differential GPS
Position’ message is displayed
on your GPS receiver,
correction data may not be
available. This may be due to a
missing or weak beacon signal,
not enough GPS satellites or
bad wiring connection between
the GBR 21 and GPS.
8) Beacon signal weak
or not received. Antenna coupler not securely
grounded. Check ground strap.
Interference from ship’s
electrical system, thunderstorm
activity, or another source is
inhibiting signal lock on.
Also refer to Troubleshooting
problems 6 and 7.
6) GPS interface
status screen displays
“No data” or “No
Signal” Wrong frequency or bit rate
selected on GPS unit.
Antenna coupler not securely
grounded. Check ground strap.
Beacon transmitter not
transmitting correction data.
9) Accuracy not as
expected Poor satellite geometry
coverage exists.
Interference to GPS antenna
and/or beacon antenna exists.
Portable antenna being used
on GPS unit. Use remote
antenna.
Multipath signals being
received by GPS unit.
Too far from DGPS transmiter
or not tuned to closest station.
7) GPS interface
status screen displays
“None”, “No Status”
or “Check Wiring” GBR 21 not wired properly with
GPS unit. Check wiring.
No power to GBR 21. See
Troubleshooting problem 1.
Problem with DGPS antenna
grounding or damage.
Baud rates do not match.
Beacon transmitter out of range.
Try a different station.
Possible Cause
If either ‘No Status’, ‘None’, or
‘Check Wiring’ messages
appear (depending upon model
of GPS) see Troubleshooting
problem number 7.
Problem