Kestrel 4000 - Manual (Page 5)

Kestrel ® 4000 Pocket Weather ® Tracker 9
SPECIAL FUNCTIONS
User Screens
The Kestrel Meter has three User Screens that can be customized to display three current
measurements simultaneously. These screens can also be turned off. (See the Main Menu
section for setup instructions.)
Max/Avg for Wind Speed & Wind Chill
The Max/Avg values for the wind speed and wind chill values are measured independently from the stored
and charted data.
This allows the user to start and stop the averaging period in the most appropriate manner for their
application. Averaging on all wind-related values (Wind Speed and Wind Chill) will be started and
stopped together.
While viewing the Min/Max/Avg screen for any of these measurements, hold the unit into the wind, and
press the button when the screen displays “--average” to begin collecting data for all measurements, and
again when the screen displays “--stop” to stop collecting data and hold the values on the display. Press the
button when the screen displays “--clear” to clear the data. This routine will work simultaneously for all
measurements, regardless of which one is displayed while the routine is run. The Max/Avg for these wind
values will not affect any other Min/Max/Avg or stored data.
Manual Data Storage
To manually store data, press the button. One of the following will appear: Data Stored (data has been
captured and will appear on chart), Full (Overwrite is off and data log is full), or Off (Manual Store button
has been disabled). (See the Main Setup Menu section for more information on memory.)
Backlight
The Kestrel Meter has a high-visibility green backlight, which makes the display easily read in low-light
conditions. The Kestrel 3500 NV has a night-vision preserving backlight which helps users to sustain natural
night vision. The NV’s backlight incorporates an optical filter to reduce overall brightness and minimize
blue and green spectrum light to preserve night vision. Additionally, the backlight is much dimmer than a
standard backlight, making it more difficult to detect with the naked eye in night operations. This backlight
appears soft greyish pink (not red) and is still in the visible spectrum, so it is not compatible with night-
vision equipment.
It takes 30 to 45 minutes for the average eye to adapt to darkness and maximize night vision. Even a short
burst of white, yellow, green or blue light “bleaches out” the rod cell photoreceptors in the eye 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.
Relative Humidity
The Kestrel Meter is capable of measuring RH to a high accuracy: +/– 3% RH between 5 and 95%. To ensure
operation within these specifications, please follow these recommendations:
• Avoid taking measurements in direct sunlight, which will heat the air inside the humidity sensor
enclosure and cause inaccurate readings.
• If your circumstances force you to expose the Kestrel Meter to a large temperature swing prior to taking
a relative humidity reading (such as when taking a Kestrel Meter stored inside at 70° F outside to a
temperature of 40° F), you will need to take additional steps to ensure that the Kestrel Meter’s external
temperature sensor is in thermal equilibrium.