NorthStar 961 Reference Manual page 141

Setting Phantom
loran GRI
961/962 Operations and Reference Manual, Rev. A
To return to displaying GPS-only coordinates, repeat the
above steps, but turn the setting of LORAN INFO BARs to
OFF.
You can choose the preferred four-digit loran GRI to use when
converting lat/lon coordinates to Phantom loran TDs. For
details about setting the loran GRI, see "Preferred loran GRI"
starting on page 13-20.
Chapter 5 - Understanding Position Coordinates
Page 5-11