RED OAKS TRADING, LTD.

Kestrel 2500 Specifications

Measurement
Response Time
Units Operational Range Resolution Accuracy (+/-) Specification Range
Wind Speed
1 second  
m/s 0.4 to 60.0 m/s 0.1 Larger of 3% of reading or least significant digit 0.4 to 40.0 m/s
ft/min 59 to 11,948 ft/min 1 59 to 7877 ft/min
km/h 1.0 to 218.0 km/h 0.1 1.0 to 144.0 km/h
mph 0.8 to 135.0 mph 1 0.8 to 89.0 mph
knots 0.6 to 118.3 kt 0.1 0.6 to 78.0 kt
Beaufort 0 to 12 B 0.1 0 to 12 B
1 inch diameter impeller with precision axle and sapphire bearings.  Off-axis accuracy -1% @ 5º off-axis; -2% @ 10º; -3% @ 15º.  Calibration drift < 1% after 100 hours use at 16 MPH / 7 m/s. Sustained operation above 60 MPH / 27 m/s will wear impeller rapidly and may cause destruction of impeller. Replacement impeller (NK PN-0801) may be field-installed without tools (US Patent 5,783,753).
Temperature  
1 second
°F -49.0 to 257.0 °F 0.1 1.8 °F -20.0 to 158.0 °F
°C -45.0 to 125.0 °C 0.1 1.0 °C -29.0 to 70.0 °C
Measures air, water and snow temperature. Thermally isolated, hermetically sealed, precision thermistor mounted externally (US Patent 5,939,645). Calibration drift negligible.
Pressure  
1 second  
(mb & PSI 4000 model only)
inHg 0.3 to 32.5 inHg 0.01 0.05 inHg At 77.0 °F, 22.1 to 32.5 inHg
hPa / mb 10.0 to 1100.0 hPa / mb 0.1 1.5 hPa / mb At 25.0 °C, 750 to 1100 hPa / mb
PSI 0.15 to 16.0 PSI 0.01 0.02 PSI At 77.0 °F, 10.9 to 16.0 PSI
Monolithic silicon piezoresistive pressure sensor with second-order temperature correction. Maximum error over temperature range 32 to 158 °F (0 to 70°C) , +/- 0.06 inHg / +/-2.0 hPa. Calibration drift typically -0.03 inHg / -1.0 hPa per year. Pressure sensor may be recalibrated at factory or in field.
Altitude  
1 second  
ft -6000 to 30000 ft 1 50 ft At 77.0 °F, <19,700 ft. Max error +/- 98 ft
m -2000 to 9000 m 1 15 m At 25.0 °C, <6,000 m.  Max error +/- 30 m
Temperature compensated pressure (barometric) altimeter. 
Wind Chill  
1 second  
°F 0.7 to 135.0 MPH, -49.0 to 257.0 °F 0.1 1.8 °F 1.8 to 89.0 mph, -50.0 to 50.0 °F
°C 0.4 to 60.0 m/s, -45.0 to 125.0 °C 0.1 1.0 °C 0.4 to 40 m/s, -45.6 to 10.0 °C
Calculated from the primary measurements of wind speed and temperature.  Utilizes 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.)
Max/Avg Wind Speed One-button clear and restart of Max Wind Gust and Average Wind measurement.
Pressure Trend Continuously updating three-hour barometric pressure trend indicator: rising rapidly, rising, steady, falling, falling rapidly.
Display Reflective 4 digit LCD.  Digit height 0.36 in / 9 mm.
Display Update 1 second.
Display Backlight Aviation green electroluminescent backlight.
Clock / Calendar Real-time hours:minutes clock.
Operational Temperature Range
(LCD and Batteries)
The operational temperature range of the liquid crystal display and batteries is 14° F to 131° F / -10 °C to 55 °C. Beyond the limits of the operational temperature range, the unit must be maintained within range and exposed for minimum time necessary to take reading.
Storage Temperature -22 °F to 140 °F / -30 °C to 60 °C.
Auto Shutdown After 45 minutes of no key presses.
Certifications CE certified. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge).  
Batteries CR2032, one, included. Average life, 300 hours of use, +/-depending on backlight use.
Environmental Waterproof (IP67 standard). Drop-tested (MIL.STD.810F; unit only. Substantial impact may damage replaceable impeller.).
Dimensions Unit 4.8 x 1.7 x 0.7 in / 122 x 42 x 18 mm. Case 4.8 x 1.9 x 1.1 in / 122 x 48 x 28 mm.
Weight Unit 2.3 oz / 65 g.  Case 1.3 oz / 37 g.
Kestrel Meters are designed and manufactured at NK’s facility in Boothwyn, Pennsylvania, and are individually calibrated at the time of manufacture. Every Kestrel Meter comes with a Certificate of Conformity to document the unit’s accuracy—all Kestrel measurements are traceable to the National Institute of Standards and Technology, ensuring the highest level of reliability.