Simrad SIMRAD HS50 Manuel D’Utilisation

MAINTENANCE 

20221081 / F 

47

 

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 

 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. 

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 

 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 

 

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.