User's Manual
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ALTIMETER
Indication of altitude in relation to sea level
Description of the function
In ALTIMETER mode, your T-Touch is transformed into a
barometric altimeter and displays the altitude in relation
to the average sea level.
Explanations
As this instrument is barometric, it calculates the altitude accor-
ding 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 measu-
ring ascents. (e. g. when hiking in the mountains).
Note: “Calibrating” an altimeter means setting it to the
actual altitude of a known point (see the setting procedure
on page 9).
The values of actual altitudes can be found from various
sources: signs, contour lines and benchmarks on maps.
The altitude “calibration” must be related to the ambient
atmospheric pressure.
Miscellaneous information
Your T-Touch 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.
Altitude [m] / [ft] Pressure [hPa] Temperature [°C] / [°F]
0 1013.25 20 / 68
114 / 374 1000 19.3 / 66.7
1007 / 3304 900 13.6 / 56.4
1985 / 6513 800 7.3 / 45.2
Technical data
Measuring range: - 400 m to +9000 m - 1300 ft to +29500 ft
Resolution:
1 m 3 ft
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 = modifi cation of altitude displayed
Thus it is necessary to “calibrate” the altimeter as often as possible.
P = pressure
Glossary
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