LORAN TD SetupLORAN C is a radio navigation aid operated and maintained in theUnited States by the United States Coast Guard. The name LORANis an acronym for “LOng RAnge Navigation.” The LORANsystem covers the entire United States and the United StatesCoastal Confluence Zone. From the perspective of a mariner, thesystem is used for ocean and coastal navigation. It can be used as asupplemental system for harbor and harbor approach navigation, andit is used for inland navigation by recreational vehicles.LORAN TD FeatureThe LORAN TD (Time Delay) feature eases the transition fromusing LORAN to using GPS. The GPSMAP 396 unit automaticallyconverts GPS coordinates to LORAN TDs for those who have acollection of LORAN fixes for favorite fishing spots and otherwaypoints recorded as TDs. You can show your location as a TDor enter waypoints as TDs. The accuracy to be expected from thisconversion is approximately thirty (30) meters. When the unit isplaced in the LORAN TD format mode, it simulates the operationof a LORAN receiver. Location coordinates can be showed as TDs,and all navigation functions can be used as if the unit was actuallyreceiving LORAN signals.Using the LORAN TD FormatWhen creating new waypoints using LORAN TD coordinates,you must set the correct LORAN chain number and secondarystations in the Setup TD field before storing the waypoint. After thewaypoint is stored in unit memory, it always reference the LORANchain number and secondary stations currently selected in theSetup TD field. If you enter a different LORAN chain number, orchange the secondary stations or offsets in the Setup TD field, theactive waypoint information does reflect those changes. Since theGPSMAP 396 does not rely on the LORAN signal for navigation,it can reference a different GRI chain and/or secondary stations andstill navigate to the location stored in memory.The LORAN Location Format field is located under the Units subtab in the Main Menu. The LORAN TD Setup window containsthe fields to select the Loran GRI-Chain Number, Primary andSecondary Stations, and TD Offsets.GPSMAP 396 Pilot’s Guide 165APPENDIX > L ORAN TD SETUP
