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Taking Direction Readings - Casio 3445 Operation Manual

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Taking Direction Readings

You can use the digital compass to determine the direction to a specifi c objective, as well as your current
position.
For information about what you can do to improve digital compass reading accuracy, see "Calibrating
the Bearing Sensor" (page E-68) and "Digital Compass Precautions" (page E-77).
To take a direction reading
You can enable a Digital Compass auto level correction function if you are having diffi culty positioning the
watch correctly while diving. If it is, the angle value will show - - - to indicate too much of a tilt. In that case,
even if a bearing is measured, correct angle display is possible.
1. Make sure the watch is in the Timekeeping Mode.
2. Place the watch on a fl at surface. If you are wearing the watch, make sure that your wrist is horizontal
(in relation to the horizon).
3. Point the 12 o'clock position of the watch in the direction whose reading you want to take.
4. Press D to start.
COMP will appear in the upper display to indicate that a digital compass operation is in progress.
About one second after you press D, graphic indicators for north, south, east, and west
will appear on the graphic dial. The bearing to your objective will also be indicated by literal
indications and a bearing angle.
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Digital Compass Readings
To restart a reading operation from the beginning, press D.
The watch will return to the Timekeeping Mode after the reading operation (which takes about 60
seconds) is complete.
Pressing C while a reading operation is in progress will return to the Timekeeping Mode.
The auto light switch is disabled during the 60 seconds that digital compass readings are being taken.
Note that taking a direction reading while the watch is not horizontal (in relation to the horizon) can
result in large direction reading error.
You can calibrate the bearing sensor if you suspect the direction reading is incorrect.
Any ongoing direction reading operation is paused temporarily while the watch is performing an alert
operation (daily alarm, Hourly Time Signal, countdown timer alarm) or while illumination is turned on (by
pressing L). The direction reading operation resumes for its remaining duration after the operation
that caused it to pause is fi nished.
See "Digital Compass Precautions" (page E-77) for important information about taking direction readings.
Example of Compass Use Under Water
While diving where there is poor illumination, where there are no reference marks, or under other
conditions where it is diffi cult to advance directly to an objective, there is the possibility that you may lose
track of your current location or the direction from which you have come. Examples of using the Digital
Compass Mode for underwater navigation is shown below. Before using the watch for such an application,
be sure to complete applicable underwater navigation training.
E-66
A: Diving straight down and then straight back up
1. With 12 o'clock of the watch pointed in the direction of your desired
Diving Mode Screen
bearing, press D to display the bearing angle in degrees (°).
Desired bearing
The watch continues to measure water depth even while it is taking
a direction reading.
2. If the resulting desired bearing angle is 100°, for example, dive straight
12 o'clock
downwards as you keep the bearing angle reading around 100° and
you count your number of fi n kicks.
3. After you reach your destination, prepare to return to your starting point
by changing your bearing by 180°. This should make the return bearing
angle your original desired bearing angle plus or minus 180°.
4. If, the return bearing angle is 280° (100°+180°) as in this example, dive
straight as you keep the bearing angle reading around 280° for the
Bearing angle (°)
required number of fi n kicks.
B: Diving in a rectangular pattern with 90° turns that take you back to your original starting point
Perform the same general steps as in example A, but each time you turn add (for a clockwise
rectangle) or subtract (for a counterclockwise rectangle) 90° at every turn.
Calibrating the Bearing Sensor
You should calibrate the bearing sensor whenever you feel that the direction readings being produced by
the watch are off. You can use any one of three different bearing sensor calibration methods: fi gure 8
calibration or 3-point calibration or magnetic declination correction. You should perform calibration
whenever direction readings produced by the watch do not match those of another reliable compass, and
before setting off on a dive. Leave the watch on your wrist when performing fi gure 8 calibration. When
performing 3-point calibration, remove the watch from your wrist.
E-68
To perform fi gure 8 calibration
1. In the Digital Compass Mode, hold down A for at least two seconds.
SET Hold will fl ash on the display and then CAL will appear. Keep
A depressed until CAL appears.
2. Press D.
Move your arm in a fi gure 8 pattern as shown in the illustration.
This will cause a fi gure 8 calibration animation to appear on the
display. After confi rming that the animation is displayed, move
your arm.
Animation
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Operation Guide 3445
Objective
12 o'clock position
North pointer
Bearing to objective:
West
Northwest
South
East
Bearing angle to objective
Note
If the four pointers (north, south, east, west) and the literal direction indication do not appear
when you press D, it could mean that the watch is displaying bearing memory information. If
this happens, press A to delete the current bearing memory contents. For more information, see
"Using Bearing Memory" (page E-76).
To return to the Timekeeping Mode, press C.
Also press C to return to the Timekeeping Mode when you want to stop a reading operation part
way through.
Underwater navigation
Example: Using your fi n kick count or some other means travel a specifi c distances as shown below
Important!
If the readings produced by the digital compass of this watch are different from those of the other
compass, perform fi gure 8 calibration or 3-point calibration of the digital compass to ensure more
accurate readings. Accurate measurements and/or calibration will not be possible in an area exposed to
strong magnetic force and indoors (especially inside reinforced concrete structure). In this case, moving
outdoors, away from the source of magnetism for measurement and calibration is recommended.
Magnetic Declination Correction
With magnetic declination correction, you input a magnetic declination angle (difference between
magnetic north and true north), which allows the watch to indicate true north. You can perform this
procedure when the magnetic declination angle is indicated on the map you are using. Note that you can
input the declination angle in whole degree units only, so you may need to round off the value specifi ed
on the map. If your map indicates the declination angle as 7.4°, you should input 7°. In the case of 7.6°
input 8°, for 7.5° you can input 7° or 8°.
Figure 8 calibration and 3-point calibration precautions
You can use any two opposing directions for fi gure 8 calibration and 3-point calibration. You must,
however, make sure that they are 180 degrees opposite each other. Remember that if you perform the
procedure incorrectly, you will get wrong bearing sensor readings.
You should perform fi gure 8 calibration or 3-point calibration in an environment that is the same as that
where you plan to be taking direction readings. If you plan to take direction readings in an open fi eld,
for example, calibrate in an open fi eld.
Note
Allow your wrist to turn as you move your arm.
Separate your arm from your body as much as possible as you move it.
When calibration is successful, OK will appear on the display and then the watch will start taking
direction readings. This indicates that calibration is complete.
If ERR appears on the display, press D and then perform the procedure from step 2 again.
Bearing Indication
Meaning
315°
N: North
E: East
W: West
S: South
Current
time
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E-67
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