106 GPSMAP 3206/3210 Owner’s ManualaPPendIX > loran td sYsteMappendIXLORAN TD SystemLORAN-C is a radio navigation aid operated and maintained in the United Statesby the United States Coast Guard. The LORAN (LOng RAnge Navigation)system covers the entire United States and the U.S. Coastal Confluence Zone.From the perspective of a mariner, the system is used for ocean and coastalnavigation. It can be used as a supplemental system for harbor and harborapproach navigation, and it is used for inland navigation by recreational vehicles.LORAN TD FeatureThe LORAN TD (Time Delay) feature eases the transition from using LORANto using GPS. The GPSMAP unit automatically converts GPS coordinates toLORAN TD for those who have a collection of LORAN fixes for favorite fishingspots and other waypoints recorded as TDs. You can display your position as aTD or enter waypoints as TDs. The accuracy to be expected from this conversionis approximately 30 meters. When the unit is placed in the LORAN TD formatmode, it simulates the operation of a LORAN receiver. Position coordinates maybe displayed as TDs, and all navigation functions may be used as if the unit wasactually receiving LORAN signals.Using the LORAN TD FormatWhen creating new waypoints using LORAN TD coordinates, you must set thecorrect LORAN chain number and secondary stations in the Setup TD fieldbefore storing a waypoint. You must have the correct chain number as well as thesecondary station identifiers to use this option correctly. These values vary foreach coordinate set or geographical location. Failure to enter correct informationcould result in inaccuracies for the desired destination. After the waypoint isstored in the unit’s memory, it always references the LORAN chain numberand secondary stations currently selected in the Setup TD field. If you enter adifferent LORAN chain number, change the secondary stations or offsets in theSetup TD field, the active waypoint information reflects those changes. Becausethe GPSMAP 3206/3210 unit does not rely on the LORAN signal for navigation,it can reference a different GRI chain or secondary stations and still navigate tothe location stored in memory.The LORAN Position Format field is located on the Units sub tab on the MainMenu—System tab. The Loran TD Setup window contains the fields to select theLORAN Chain Number, Primary and Secondary Stations, and TD Offsets.To set up LORAN TD from the Main Menu:1. Using the ROCKER, highlight the System tab, press right on the ROCKERto highlight the Units sub tab. Highlight the Position Format field, andpress ENTER.2. Highlight Loran TD, and press ENTER, and then highlight the Setupbutton to the right, and press ENTER again.3. To change the settings of any of the five fields, highlight the field, pressENTER, select the setting you want, and press ENTER again.