Flytec Alti Windwatch - Manual (Page 9)

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7
Setting the time
Holding down the
● ▲ key for a long time
(3 seconds) will change from the main menu
to Option mode. The currently entered time
will flash.
The time can be put back with the
●
▼ key
and put forward with the ●
▲ key. Either press
the key briefly to alter the time displayed
in one-minute increments or hold it down
continuously for fast resetting.
Save your entry by pressing both keys
●
▼
● ▲
simultaneously or wait 8 seconds; the display
will change from Option mode to the main
menu.
Time
Barometer/Time
Option mode
An altimeter measures the altitude on the
basis of air pressure. The air pressure at sea
level is assumed to be zero pressure. This
zero pressure is called QNH. Dependent on
weather conditions, the air pressure at sea
level fluctuates between 950 and 1050 milli-
bars. Even on a stable day, there can be fluct-
uations in the air pressure of ±1 mbar due to
the temperature and this corresponds to a
deviation in altitude of ± 8 meters.
When the weather is changing fast, for
example, cold fronts, the air pressure can
change by up to 5 mbars in one day and the
deviation in altitude can amount to up to
40 meters. Owing to these fluctuations in air
pressure, an altimeter must be recalibrated
each time it is used. This means that the
altimeter must be reset at a known altitude
(e. g. at home, at a railway station, at a ski hut,
etc.).
Altimeter
General remarks