Simrad HS50 - Manual (Page 55)

MAINTENANCE
20221081 / F
47
No Differential corrections
The possible reason for a white box for differential correction
indication (DIF) could be one of the following:
• No differential corrections are input through terminal port
P205 or P206 on the Processing unit. If differential
corrections are input through one of these terminal ports,
check that the parameters are properly set up in the Display
unit setup menu Diff. input, see Differential corrections,
page 26.
• You can be out of range to a radio reference station and the
differential corrections are therefore missing. If the reference
station is too far away or it is in the shadow of geographical
obstructions or other equipment on board, reception may be
unreliable or missing. Pressing the
INFO button and the
display GPS Information shows the identification number of
the reference stations connected to the HS50.
• The reference station can be out of function. Check the status
of the reference station with the authorities responsible for it,
or consult your nearest Simrad dealer for assistance.
Invalid Heading
The possible problem can be one of the following:
• The number of GPS satellites the Sensor unit is able to see is
too few. Press the NAV2/POS button until the Skyplot view
appears. Check that at least four satellites are available and
that the PDOP value is less than 6. Refer Satellite Skyplot
display, page 37. Check also the number of common
satellites seen by the two GPS antennas by pressing the
INFO
button and looking at the value for Common sat. in the
advanced heading information display as shown in page 38.
The number of common satellites have to be two or higher to
determine a heading.
If one of the criteria's above is not fulfilled, the mounting
location of the Sensor unit may not be suitable or there may be
an obstruction between the Sensor unit and the GPS satellites.
Check the mounting location and consider relocation according
to Location of the unit, page 10.
If it is still not working after checking the above items, consult
your nearest Simrad dealer for assistance.