Timex Intelligent Quartz Manual page 162

COMPASS CALIBRATION
Before use, the compass must be calibrated.
Since a compass uses the earth's magnetic field, you
must be aware of large metallic objects, such as vehicles
or bridges, or objects that give off electromagnetic
radiation, such as televisions or computers, which
could affect the magnetic field around the watch. If the
compass is calibrated near such objects, it will only
work properly in that same location. If the compass
is calibrated away from such objects, it will not work
properly near them. For best results, calibrate in the area
of intended use.
In calibrating and taking headings, it is important, as with
all compasses, to keep the compass level. Calibrating or
taking a heading when the watch is not level can result
in large errors. Also avoid areas that may exhibit higher
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