There are many reasons for such bearing diference between radars.
Briefly.
The difference on bearings is not directly related with wave length ( S ,X or T )
Location of radar on the mast ( greater difference as the target gets closer )
Heading line alignment error. ( you can correct it through service menus ) do not mix with gyro heading it comes from gyro itself.
Check with ECDİS ( use radar overlay function )
Take visual bearing and compare with both radars ( ı believe you’ve already done it )
If you are too close to the shore ( i.e. rivers or eustuaries ) such difference do occur try visuals or PI.
Capt. Melih AKGUL, MNI
[QUOTE=aryk4;162241]Greetings all,
I’m a relatively new mate (1 year as OOW), and I haven’t run across this before in training. We’re anchored and the captain is ashore; this issue was noticed by another mate this morning just before watch handover. We have had work done on the radars over the past few days.
[B]Problem:
[/B]EBL bearings on the X and the S band radars don’t agree. [B]
Observations:[/B]
The ship’s heading on the radar agrees with the gyro.
The GPS coordinates for both ownship and targets agree between radars.
Ranges to both the cursor and to fixed objects agree.
Target SOG and ranges agree.
BUT, target bearings to ownship and target COG are off, both by about 10 degrees.
[B]Question:[/B] How can I tell which one is correct?
I’ve tried a few things, but I’d like to see what the internet says. Any insight or advice you have would be very much appreciated. Thanks![/QUOTE]