| Primary Measurement |
Units |
Resolution |
Accuracy
(+/-) |
Range:
Max
Operational
Specification
(if less) |
Notes |
Wind Speed
or Air Velocity |
m/s |
0.1 |
Larger of 3% of reading, least significant digit or 20 ft/min |
0.6 to 60.0 m/s
0.6 to 40.0 m/s |
1 inch diameter impeller with precision axle and low-friction Zytel® bearings.
Start-up speed stated as lower limit, readings may be taken down to 0.4 m/s | 79 ft/min | 1.5 km/h | .9 mph | .8 kt after impeller start-up.
Off-axis accuracy -1% @ 5° off-axis; -2% @ 10° -3% @ 15°.
Calibration drift < 1% after 100 hours use at 16 MPH | 7 m/s.
Replacement impeller (NK PN-0801) field installs without tools (US Patent 5,783,753). |
| ft/min |
1 |
18 to 11,811 ft/min
118 to 7,874 ft/min |
| km/h |
0.1 |
2.2 to 216.0 km/h
2.2 to 144.0 km/h |
| mph |
0.1 |
1.3 to 134.2 mph
1.3 to 89.5 mph |
| knots |
0.1 |
1.2 to 116.6 knots
1.2 to 77.8 knots |
| Beaufort |
1 |
0 to 12 B |
| Temperature |
°F |
0.1 |
1.8 °F |
-49.0 to 257.0
-20.0 to 158.0 |
Air, water or snow temperature. Hermetically-sealed, precision thermistor mounted externally and thermally isolated (US Patent 5,939,645) for rapid response. Airflow of 2.2 mph | 1 m/s or greater provides fastest response and reduction of insulation effect. Calibration drift negligible. |
| °C |
0.1 |
1.0 °C |
-45.0 to 125.0
-29.0 to 70.0 |
| Relative Humidity |
%RH |
0.1 |
3.0 %RH |
0.0 to 100.0%
5.0 to 95.0% non-condensing |
Polymer capacitive humidity sensor mounted in thin-walled chamber external to case for rapid, accurate response (US Patent 6,257,074). To achieve stated accuracy, unit must be permitted to equilibrate to external temperature when exposed to large, rapid temperature changes and be kept out of direct sunlight. Calibration drift +/- 2% over 24 months. RH may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802). |
| Wind Chill |
°F |
0.1 |
1.8 °F |
Refer to stated ranges for wind speed and temp. |
Perceived temperature resulting from combined effect of wind speed and temperature. Calculated based on the NWS Wind Chill Temperature (WCT) Index, revised 2001, with wind speed adjusted by a factor of 1.5 to yield equivalent results to wind speed measured at 10 m above ground. Specification temperature limits established by WCT Tables. |
| °C |
0.1 |
1.0 °C |
| Heat Index |
°F |
0.1 |
3.6 °F |
Refer to stated ranges for temp. and relative humidity. |
Perceived temperature resulting from the combined effect of temperature and relative humidity. Calculated based on NWS Heat Index (HI) tables. (Specification temperature limits established by HI tables.) |
| °C |
0.1 |
2.0 °C |
| Dewpoint |
°F |
0.1 |
3.6 °F |
Refer to stated ranges for temp. and relative humidity. |
Temperature to which the air must be cooled at a constant pressure for water vapour to condense into water. Calculated from temperature and relative humidity. |
| °C |
0.1 |
2.0 °C |
| Max/Avg Wind |
One-button clear and restart of Max Wind Gust and Average Wind measurement by powering down and restarting unit. |
| Display & Backlight |
Reflective 3 1/2 digit LCD. Digit height 0.36 in / 9 mm. Aviation green electroluminescent backlight (except in Kestrel 1000). Manual activation with auto-off. |
| Response Time & Display Update |
All measurements except those based on relative humidity respond accurately within 1 second. Relative humidity and all measurements which include RH in their calculation may require as long as 1 minute to fully equilibrate to a large change in the measurement environment. Display updates every 1 second. |
| Operational & Storage Temperature Range |
The operational temperature range of the liquid crystal display and batteries is 14° F to 131° F / -10 °C to 55 °C. Measurements beyond the operational range can be taken by briefly exposing unit to extreme conditions such that the display and batteries remain within the operational range. Storage range -22 °F to 140 °F / -30 °C to 60 °C. |
| Auto Shutdown |
After 45 minutes of no key presses. |
| Certifications |
CE certified, RoHS and WEEE compliant. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge). |
| Battery |
CR2032, one, included. Average life, 300 hours. Battery life reduced by backlight use in 2000 to 3500 models. |
| Environmental |
Waterproof (IP67 and NEMA-6). MIL-STD-810F, Transit Shock, Method 516.5 Procedure IV; unit only; impact may damage replaceable impeller. |
| Size & Weight |
4.8 x 1.9 x 1.1 in / 12.2 x 4.8 x 2.8 cm, 3.6 oz / 102 g (including slip-on cover). |
| Colour Options |
Maroon |
