Garmin GPSMAP 3010C - Manual (Page 114)

106 GPSMAP 3006C/3010C Owner’s Manual
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LORAN TD System
LORAN-C is a radio navigation aid operated and maintained in the United States
by 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 coastal
navigation. It can be used as a supplemental system for harbor and harbor
approach navigation, and it is used for inland navigation by recreational vehicles.
LORAN TD Feature
The LORAN TD (Time Delay) feature eases the transition from using LORAN
to using GPS. The GPSMAP unit automatically converts GPS coordinates to
LORAN TD for those who have a collection of LORAN fixes for favorite fishing
spots and other waypoints recorded as TDs. You can display your position as a
TD or enter waypoints as TDs. The accuracy to be expected from this conversion
is approximately 30 meters. When the unit is placed in the LORAN TD format
mode, it simulates the operation of a LORAN receiver. Position coordinates may
be displayed as TDs, and all navigation functions may be used as if the unit was
actually receiving LORAN signals.
Using the LORAN TD Format
When creating new waypoints using LORAN TD coordinates, you must set the
correct LORAN chain number and secondary stations in the Setup tD field
before storing a waypoint. You must have the correct chain number as well
as the secondary station identifiers to use this option correctly. These values
vary for each coordinate set or geographical location. Failure to enter correct
information could result in inaccuracies for the desired destination. After the
waypoint is stored in the unit’s memory, it always references the LORAN chain
number and secondary stations currently selected in the Setup tD field. If you
enter a different LORAN chain number, change the secondary stations or offsets
in the Setup TD field, the active waypoint information reflects those changes.
Because the GPSMAP 3006C/3010C unit does not rely on the LORAN signal for
navigation, it can reference a different GRI chain or secondary stations and still
navigate to the location stored in memory.
The LORAN Position Format field is located on the Units sub tab on the Main
Menu—System tab. The Loran TD Setup window contains the fields to select the
LORAN 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
ROCKER to highlight the Units sub tab. Highlight the Position Format
field, and press ENTER.
2. Highlight Loran TD, and press ENTER, and then highlight the Setup
button to the right, and press ENTER again.
3. To change the settings of any of the five fields, highlight the field, press
ENTER, select the setting you want, and press ENTER again.