Garmin GPSMAP 178C Owner's Manual

Also see for GPSMAP 178C: Specifications Flush Mount Template Manual Owner's manual

Contents

Garmin GPSMAP 178C Owner's Manual Manual pdf 112 page image

On the Units Tab of the Main Menu, pressMENU, then highlight ‘Loran TD On’ andpress ENTER to select Loran TD.Or, highlight the Position Format field,highlight ‘Loran TD’ and press ENTER toselect Loran TD.102Appendix BLoran TDLoran TD SystemLORAN-C is a radio navigation aid operated and maintained in the United States by the UnitedStates Coast Guard. The name LORAN is an acronym for “LOng RAnge Navigation”. The LORANsystem covers the entire United States and the U.S. Coastal Confluence Zone. From the perspective ofa mariner, the system is used for ocean and coastal navigation. It can be used as a supplemental systemfor harbor and harbor approach navigation, and it is used for inland navigation by recreational vehicles.LORAN TD FeatureThe LORAN TD (Time Delay) feature eases the transition from using LORAN to using GPS. TheGPSMAP unit automatically converts GPS coordinates to LORAN TDs for those who have a collec-tion of LORAN fixes for favorite fi shing spots and other waypoints recorded as TDs. You can displayyour position as a TD or enter waypoints as TDs. The accuracy to be expected from this conversion isapproximately thirty meters. When the unit is placed in the LORAN TD format mode, it simulates theoperation of a LORAN receiver. Position coordinates may be displayed as TDs, and all navigation func-tions may be used as if the unit was actually receiving LORAN signals.Using the LORAN TD FormatWhen creating new waypoints using LORAN TD coordinates, you must set the correct LORANchain number and secondary stations in the Setup TD field before storing the waypoint. You must havethe correct chain number as well as the secondary station identifiers to use this option correctly. Thesevalues vary per coordinate set or geographical location. Failure to enter correct information could resultin inaccuracies for the desired destination. After the waypoint is stored in unit memory, it always refer-ences the LORAN chain number and secondary stations currently selected in the Setup TD field. If youenter a different LORAN chain number, change the secondary stations or offsets in the Setup TD field,the active waypoint information reflects those changes. Since the GPSMAP unit does not rely on theLORAN signal for navigation, it can reference a different GRI chain and/or secondary stations and stillnavigate to the location stored in memory.