Using Phantom Loran - NorthStar 972 Quickstart Manual And Reference Manual

Using Phantom Loran

If you have lists of fishing spots and other
waypoints that you recorded as loran time
differences (TDs), but you no longer have a
loran receiver, the 972 can automatically
convert its GPS coordinates into TDs — in
real time, as you travel. You can display
your current position as TDs or navigate to
waypoints using TDs. The accuracy from
this conversion is generally 500 to 1500
feet.
This feature, called Phantom Loran, can
help your transition from loran to GPS. You
can use the 972 to simulate the full opera-
tion of a loran receiver, using all of the
972's navigation functions as if it were
actually receiving loran signals.
These calculated TDs won't exactly match
the positions of previously recorded TDs
obtained directly from actual loran signals.
In most areas, TD errors shouldn't exceed
one microsecond. However, larger errors
are possible in areas with poor station
geometry, or for which the 972 doesn't
have accurate, factory-programmed ASF
correction points.
Selecting Phantom Loran
To display position coordinates as
Phantom Loran TDs, press the
Reference Manual Revision B
key a second time to display the
screen
Loran
Press it again to return to lat/lon
coordinates.
Setting the Phantom Loran GRI
Press Set GRI to change the GRI to be used
in calculating the displayed TDs. Press the
cursor pad to display the available GRIs
one at a time. When the GRI is correct,
press
ENTER
Press TD pair several times to display the
pair of TDs you want to use.
POSITION
Reference section 3 — Position coordinates
Phantom
.
.
Phantom Loran screen

Using Phantom Loran

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