Garmin GPSMAP 496 - Manual (Page 173)

GPSMAP 496 Owner’s Manual 65
Appendix > Loran TD Setup
LORAN TD Setup
LORAN is a radio navigation aid operated and maintained in the
United States by the United States Coast Guard. The name LORAN
is an acronym for “LOng RAnge Navigation”. The LORAN
system covers the entire United States and the United States
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 496 unit automatically
converts GPS coordinates to LORAN TDs for those who have a
collection of LORAN fixes for favorite fishing spots and other
waypoints recorded as TDs. You can show your location as a TD
or enter waypoints as TDs. The accuracy to be expected from this
conversion is approximately thirty (30) meters. When the unit is
placed in the LORAN TD format mode, it simulates the operation
of a LORAN receiver. Location coordinates can be showed as TDs,
and all navigation functions can 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 the waypoint. After the
waypoint is stored in unit memory, it always reference the LORAN
chain number and secondary stations currently selected in the
Setup TD field. If you enter a different LORAN chain number, or
change the secondary stations or offsets in the Setup TD field, the
active waypoint information does reflect those changes. Since the
GPSMAP 496 does not rely on the LORAN signal for navigation,
it can reference a different GRI chain and/or secondary stations and
still navigate to the location stored in memory.
The LORAN Location Format field is located under the Units sub
tab in the Main Menu. The LORAN TD Setup window contains
the fields to select the Loran GRI-Chain Number, Primary and
Secondary Stations, and TD Offsets.