Furuno GP-1870F, Operator'S Manual

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11. CUSTOMIZING YOUR UNIT
11-4
[SPEED FILTER]: During position fixing, ship's velocity (speed) is directly measured
from the GPS satellite. The raw velocity data may change randomly depending on re-
ceiving conditions and other factors. You can reduce this random variation by increas-
ing the filter setting. Like with the latitude and longitude filter, the higher the speed filter
setting the more smoothed the raw data. If the setting is too high, however, the re-
sponse to speed and course change slows. For no smoothing, choose Off.
[FIX DATUM]: Select the datum used to prepare your chart.
[NAVIGATION SETUP] : Navigate provides for customizing of the map display.
[COORDINATE SYSTEM]: Select the coordinate display method, among
ddd.mm.mmm, ddd.mm.mmmm, ddd.mm.ss, or TD (Loran C).
[LORAN C SETTINGS]: Set Loran C settings, when [TD] is selected as the coordinate
system, referring to the table below. For details on Loran C settings, see the operator’s
manual of your Loran C receiver.
[MAP DATUM]: Select the datum.
[ROTATION OF THRESHOLD]: Sets the amount of course (in degrees) that initiates
redrawing of the course in the Auto course-up mode.
[COMPASS SETUP] : Select the type of compass used and set magnetic variation.
[BEARINGS]: Select True for gyrocompass, Magnetic for magnetic compass.
[VARIATION]: The location of the magnetic north pole is different from the geograph-
ical north pole. This causes a difference between the true and magnetic north location.
Item Description
CHAIN Select the Loran C chain to use
SECONDARY STATION 1,
SECONDARY STATION 2 Set the secondary stations to use.
ASF 1, ASF 2 Set additional secondary factors.
ALTER Due to the nature of Loran your position in latitude and longitude can
be on either side of the baseline, which is an imaginary line connect-
ing two stations in a straight line. These two positions are called the
primary and alternate solutions. They are usually far apart, so it is
easy to tell if Loran is displaying a position far from your actual loca-
tion. If the primary position appears to be wrong, switch to the alter-
nate position by turning on the [ALTER] feature.
NAVIGATION SETUP
COORDINATE SYSTEM dd.mm.mmmm
LORAN C SETTINGS
MAP DATUM WGS 1984
ROTATION THRESHOLD 30