Kestrel
®
4500 Pocket Weather
®
Tracker
and causes night blindness until the entire adaptation process can take place again. Light in the red
spectrum does not cause this “bleaching out”, preventing night blindness and night vision fatigue.
Press the
button to activate the backlight. The light will remain activated for one minute. Press the
button within one minute to deactivate the light manually.
Measuring Direction
Before you begin, there are three simple things that are important to understand before using the
Kestrel 4500 to take compass readings:
1. Because the Kestrel 4500 is designed primarily to measure wind direction, the digital compass
component is aligned to work with the Kestrel Meter held vertically, in the same orientation used
when measuring wind. As is the case with all compasses, the compass component must be level to
yield accurate readings. To maximize the accuracy of compass readings, the Kestrel 4500 must be
positioned as close to the vertical as possible (front/back and left/right) when using any compass-
related feature (direction, crosswind, headwind, calibration). For every degree off vertical that the
unit is positioned, compass readings may vary up to three degrees.
2. The Kestrel Meter uses two AAA batteries to power the unit. These batteries have a magnetic
signature that can influence the compass readings if not properly calibrated. After installing or
replacing the batteries, you must execute the simple self-calibration routine (see the Calibrating the
Digital Compass section) to ensure that the effect of the batteries is negated. If your unit has not
been calibrated, it will NOT measure direction and will post the message “uncalibrated” at the base
of any direction screen.
3. The impeller of the Kestrel 4500 also contains a small magnet that may slightly influence the
compass readings when the impeller is still or rocking slightly. For maximum accuracy of compass
readings, the impeller should be spinning (or removed).
