Kestrel 4000 - Manual (Page 7)

Kestrel ® 4000 Pocket Weather ® Tracker 13
barometric pressure. Your altitude as shown on the ALTITUDE screen will change as the weather changes,
but you can ignore this screen for this purpose.
If you are planning a day hike would like to track your altitude, you’ll need to enter the correct reference
pressure on the ALTITUDE screen as described above in “starting with the known barometric pressure.”
You can now track the altitude changes as you hike. In this instance, you should ignore the values on the
BARO screen, since the pressure changes will be due to changes in elevation far more than to changes in
the weather.
In general, changes in barometric pressure associated with weather changes are small over the course of
one day, but they will affect the accuracy of the altimeter over time. This is why aircraft reset their altimeters
at every airfield by entering the field’s “altimeter setting” or reference pressure. Accordingly, if accurate
altitude readings are your primary interest, you should reset the reference pressure on your Kestrel Meter
regularly. If you encounter an elevation landmark, you can adjust the reference pressure until the altitude
matches the landmark elevation. This will correct the altitude for any pressure changes due to the weather.
(Or, you can obtain an updated reference pressure from the sources described above.)
Some final notes - If you wish to know the actual or station pressure for your location (such as for engine
tuning), simply set the reference altitude on the BARO screen to “0”. In this case, the Kestrel Meter will
not make any adjustment and will display the measured value. (Engine tuning and ballistics software
sometimes refer to atmospheric or station pressure as “absolute pressure.” These applications are
concerned with the actual air density, as opposed to pressure gradients relating to weather, so barometric
pressure is less useful.)
Also, the above discussion applies to ALL pressure altimeters, including one you may have in a watch or
other device, but not to GPS altimeters, which use satellite triangulation to determine altitude. Note that
with present GPS technology, pressure altimeters remain more accurate for measuring altitude change. This
is why airplanes still rely on pressure altimeters, not GPS.
Finally, the DENSITY ALTITUDE screen is calculated from the absolute values of station pressure,
relative humidity and temperature, and is not affected by the reference values entered in the BARO and
ALTITUDE screens.
MAIN SETUP MENU
You can customize your Kestrel Meter in multiple ways. Press the button to access the Main Setup Menu.
Press the button to select the highlighted setting. The Main Setup Menu contains: OFF, Memory Options,
Measurements, Graph Scale, Units, User Screens, System, Date & Time, Language and Restore.
Off
Press the then the button to turn the display off. Even when the Kestrel Meter’s display is turned
off, the unit will continue to automatically store data at the defined Store Rate. The battery life will be
decreased if data is stored frequently. The only way to completely shut off the unit is to remove the
batteries. Custom settings and data will be stored when the batteries are removed.
Memory Options
These settings control the data storage properties.
Setting Description Operation
Clear Log
(Go/Done) All stored data is cleared. This will also clear
Min/Max/Avg data.
Press or to clear the log.
Reset MMA
(Go/Done) All Min/Max/Avg data is cleared. Chart data
will remain intact.
Press or to clear the MMA.