Suunto X9_en manual ALTI/BARO Mode, Use

3.3.ALTI/BARO MODE

The Alti/Baro mode is used for measuring altitude, barometric pressure and temperature. Suunto X9 calculates the altitude from the current barometric pressure, which is more sensitive

and accurate than the altitude measurement with the GPS, and is also available when the GPS is off.

Because both altitude and weather data are measured with the same barometric sensor, you have to select whether you want to use this mode as an altimeter or as a weather station.

The Use selection defines the set of information shown on the main display. The Alti/ Baro menu also contains weather and altitude alarms, the weather memory, and the reference setting needed to relate the current weather state with your current altitude.

3.3.1. Use

With this function you can set Suunto X9 to display either barometric or altitude-related information.

When the Alti use is active, Suunto X9 assumes that all the barometric pressure changes are due to altitude changes. Alti is intended for measuring altitude whenever you are on the move. However, since substantial barometric pressure changes can take place during a day, you should compare the changes reported by Suunto X9 to well-known references. If these differ from each other too much, the reason is the weather change and you should set a new reference value as advised in section 3.3.5. Reference altitude and barometric pressure. A general rule is that a 10 m change in altitude equals 1,2 hPa in the barometric pressure at sea level and 0,5 hPa at 8000 m. When the Baro use is active, Suunto X9 assumes that all the barometric pressure changes are due to weather changes. Baro use is practical for following and predicting weather trends when staying in a constant altitude. When the GPS is on, the device uses the atmospheric pressure to measure the altitude reading just like when Alti is set, regardless of which display is selected, Alti or Baro.

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