21
20
ALTIMETER
Indication of altitude in relation to sea level
Description of the function
In ALTIMETER mode, your watch is transformed into a
barometric altimeter and displays the altitude in
relation to the average sea level.
Explanations
Warning!
As pressure is used to calculate the altitude, the altimeter is sensitive to variations in
atmospheric pressure as the weather changes. It is not uncommon to see differences in
altitude of 100 m in one night.
The value displayed may vary without your altitude actually changing.
Change in weather = variation in pressure = modification of altitude displayed
Thus it is necessary to "calibrate" the altimeter as often as possible.
P = pressure
0m
500m
1000m
1500m
2000m
540 m
540 m
As this instrument is barometric, it calculates the altitude
according to atmospheric pressure.
As altitude increases, pressure decreases and vice versa.
Therefore, the altimeter measures the difference in
pressure and displays the altitude. It is therefore an ideal
instrument for measuring ascents. (e. g. when hiking in the
mountains).
Miscellaneous information
Technical data
Measuring range:
- 400 m to +9000 m
- 1300 ft to +29500 ft
Resolution:
1 m
3 ft
540 m
540 m
780 m
Altitude [m] / [ft]
Pressure [hPa]
Temperature [˚C]/[˚F]
0
1013.25
20 / 68
111 / 364
1000
19.3 / 66.7
988 / 3242
900
13.6 / 56.4
1949 / 6395
800
7.3 / 45.2
Note: "Calibrating" an altimeter means setting it
to the actual altitude of a known point (see the
setting procedure on page 14).
The values of actual altitudes can be found from
various sources: signs, contour lines and
benchmarks on maps.
Your watch compensates for temperature.
The altitude displayed is therefore corrected automatically.
The altimeter makes a measurement every 10 seconds.
Your altimeter will not show the variations in altitude in an aircraft
as the cabin is pressurised (constant pressure).
Unit conversion: 1 metre [m] = 3.281 feet [ft]
1 foot [ft]
= 0.305 metres [m]
Average pressure, at sea level: 1013.25 hPa
Average variation in pressure and temperature depending on altitude:
G
L O S S A R Y
G
L O S S A R Y
Manuel Ham_GB_2e manuel.qnx 1.10.2001 16:22 Page 20
