Humminbird NS 10 Operation Manual page 19

Use the up/down arrows to choose LORAN TD or LAT/LON coordinates.
Press ENTER when the setting is correct.
If you choose LORAN TD the SELECT GRI menu will be displayed. You must choose the group
repetition interval. (Refer to section X. Glossary)
Use the up/down arrow to select the GRI setting.
Press ENTER when the setting is correct. You will be asked to choose a secondary station.
Use the up/down arrows to choose the first secondary station.
Press ENTER when setting is correct. You will be asked to choose another secondary stayion.
Use the up/down arrows to choose the second secondary station.
Press ENTER when the setting is correct.
Note: Loran TD's cannot be directly entered when using the waypoint menus. Only latitude and
longitude positions can be entered in the waypoint menus.