NorthStar 941X Reference Manual page 91

magnetic
variation
Rev. D
GPS can be selected as the navigation source at any time.
EXTERNAL LORAN can be used if a loran receiver is interfaced
to the 941X (and is operational).
PHANTOM LORAN can be used if no loran receiver is inter-
faced to the system, but you'd like to see your position displayed
in TD coordinates.
DEMO mode is used to simulate a stationary position—namely,
the unit's last position fix—if you want to practice using the 941X
without being on your boat or connected to an antenna. You may
enter a waypoint with the name "DEMO" to establish a new
demo position at that waypoint's coordinates.
If your 941X is equipped with an internal beacon receiver, dif-
ferential GPS corrections (if available) will always be used
when "GPS" or "Phantom Loran" is selected as the navigation
source.
(NAVIGATION OPTIONS) (NAVIGATION OPTIONS)
(NAVIGATION OPTIONS) (NAVIGATION OPTIONS)
Compasses naturally point to the magnetic north pole, which is several
hundred miles from the Earth's actual north pole. The difference be-
tween the two angles is known as magnetic variation . The 941X offers
you the option of choosing from True
lates variation automatically, according to your location), and Manual
(from 0° to 180°, East or West) settings. The factory default is magnetic,
to coincide with your compass. Your navigation charts will indicate the
approximate magnetic variation for each area.
Under most conditions, you'll want the 941X to calculate the variation
automatically for your position. (Usually, the automatically-calculated
variation is entirely adequate for use.)
True bearings are usually required when using a gyrocompass.
The manual setting (1° to 180°) is available for those times when the dis-
play must match an older or less accurate chart, or in remote areas (usu-
ally above 70° latitude) where magnetic calculations can be off by as
much as a degree or more.
8 — Customizing the 941X 8 — Customizing the 941X 8 — Customizing the 941X 8 — Customizing the 941X
NOTE
True (0°), Automatic True True Automatic (the 941X calcu- Automatic Automatic
Manual Manual Manual
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