Kestrel 2500 Pocket Wind Meter

Category: Kestrel USA Meters

 

Overview

The Kestrel 2500 takes the great features of the Kestrel 2000 and adds in a pressure sensor. A three-hour pressure trend indicator helps you predict fish and wildlife activity and know when the weather's going to turn nasty. With its easy-to-use digital pressure altimeter, you have the perfect instrument for any outdoor activity.

In addition to predicting weather activity, barometric pressure also influences a bullet’s trajectory, which is why the Kestrel 2500 is used by shooters and hunters when accuracy is important. US Olympic Rifle Champion Shooter Lones Wigger wouldn’t trust any other instrument. “The Kestrel Meter is essential for target rifle shooting. It helps me win matches, and I rely on it for accurate weather information.”

Available in the NV Configuration

Military personnel and pilots flying in darkness are often concerned with preserving their night vision. Due to overwhelming demand from our military customers, the Kestrel NV line was added in 2005.

The Kestrel 2500NV 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, NV backlights are also 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 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.

Kestrel 2500 Measures

Kestrel 2500 Features

  • Real-time clock
  • Protective cover with sure-grip overmolding
  • Data hold function
  • Large easy-to-read display with backlight
  • Waterproof and floats
  • Innovative design for stability and accuracy in abrupt condition changes
  • Patented user-replaceable impeller
  • Quick response, external thermistor
  • High precision pressure sensor
  • Reliable, portable and easy to use
  • All instruments and accessories are completely assembled in the USA
  • 5-year warranty

Kestrel 2500 Includes

 

 

 

SENSORS
SENSOR 1000 2000 2500 3000 3500 3500
DT
4000 4200 4250 4300 4400 4500 4500
HOR
ACCURACY (+/-)* RESOLUTION SPECIFICATION RANGE OPERATIONAL RANGE NOTES
Wind Speed | Air Flow Larger of 3% of reading, least significant digit or 20 ft/min 0.1 m/s
1 ft/min
0.1 km/h
0.1 mph
0.1 knots
1 B
0.6 to 40.0 m/s
118 to 7,874 ft/min
2.2 to 144.0 km/h
1.3 to 89.5 mph
1.2 to 77.8 knots
0 to 12 B
0.6 to 60.0 m/s
118 to 11,811 ft/min
2.2 to 216.0 km/h
1.3 to 134.2 mph
1.2 to 116.6 knots
0 to 12 B
1 inch|25 mm diameter impeller with precision axle and low-friction Zytel® bearings. Startup 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 startup. Off-axis accuracy -1% @ 5º off-axis; -2% @ 10º; -3% @ 15º. 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). Wind speed calibration and testing should be done with triangle on impeller located at the top front face of the Kestrel.
Ambient Temperature   0.9 °F
0.5 °C
0.1 °F
0.1 °C
-20.0 to 158.0 °F
-29.0 to 70.0 °C
14.0.0 to 131.0 °F
-10.0 to 55.0 °C
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 insolation effect. Calibration drift negligible. Thermistor may also be used to measure temperature of water or snow by submerging thermistor portion into material -- remove impeller prior to taking submerged measurements and ensure humidity sensor membrane is free of liquid water prior to taking humidity based measurements after submersion.
Globe Temperature - Tg                         °F
1.4 °C
0.1 °F
0.1 °C
-20.0 to 140.0 °F
-29.0 to 60.0 °C
14.0 to 131.0 °F
-10.0 to 55.0 °C
Temperature inside 1in|25 mm black powder coated copper globe converted to Tg equivalent for standard 6 in|150 mm globe. Closest equivalence obtained with airflow greater than 2.2 mph|1 m/s.
Relative Humidity       3.0 %RH 0.1 %RH 5 to 95%
non-condensing
0 to 100% 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. Humidity sensor may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802).
Pressure       0.03 inHg
1.0 hPa|mbar
0.01 PSI
0.01 inHg
0.1 hPa|mbar
0.01 PSI
8.86 to 32.49 inHg
300.0 to 1100.0 hPa|mbar
4.35 to 15.95 PSI
and
32.0 to 185.0 °F
0.0 to 85.0 °C
0.30 to 48.87 inHg
10.0 to 1654.7 hPa|mbar
0.14 to 24.00 PSI
and
14.0 to 131.0 °F
-10.0 to 55.0 °C
Monolithic silicon piezoresistive pressure sensor with second-order temperature correction. Pressure sensor may be recalibrated at factory or in field. Adjustable reference altitude allows display of station pressure or barometric pressure corrected to MSL. Kestrel 4200 displays station pressure on a dedicated screen. Kestrel 2500 and 3500 display continuously updating three-hour barometric pressure trend indicator: rising rapidly, rising, steady, falling, falling rapidly. Kestrel 4000 series displays pressure trend through graphing function. PSI display on Kestrel 4000 series only.
Compass                      
1/16th Cardinal Scale
0 to 360° 0 to 360° 2-axis solid-state magnetoresistive sensor mounted perpendicular to unit plane. Accuracy of sensor dependent upon unit's vertical position. Self-calibration routine eliminates magnetic error from batteries or unit and must be run after every full power-down (battery removal or change). Readout indicates direction to which the back of the unit is pointed when held in a vertical orientation. Declination/variation adjustable for True North readout.
CALCULATED MEASUREMENTS
MEASUREMENT 1000 2000 2500 3000 3500 3500
DT
4000 4200 4250 4300 4400 4500 4500
HOR
ACCURACY (+/-)* RESOLUTION SPECIFICATION RANGE SENSORS EMPLOYED NOTES
Air Density                         0.0002 lb/ft3
0.0033 kg/m
3
0.001 lbs/ft3
0.001 kg/m
3
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Mass of air per unit volume
Air Flow                         6.71% 1 cfm
1 m3/hr
1 m
3/m
0.1m
3/s
1 L/s
Refer to Ranges for Sensors Employed Air Flow
User Input (Duct Shape & Size)
Volume of air flowing through an opening. Automatically calculated from Air Velocity measurement and user-specified duct shape (circle or rectangle) and dimensions (units: in, ft, cm or m). Maximum duct dimension input: 258.0 in | 21.5 ft | 655.3 cm | 6.55 m.
Altitude       typical: 23.6 ft
7.2 m
max: 48.2 ft
14.7 m
1 ft
1 m
typical: 750 to 1100 mBar

max: 300 to 750 mBar
Pressure
User Input (Reference Pressure)
Height above Mean Sea Level ("MSL"). Temperature compensated pressure (barometric) altimeter requires accurate reference barometric pressure to produce maximum absolute accuracy. Both accuracy specs corresponds to a reference pressure anywhere from 850 to 1100 mBar.
Barometric Pressure       0.07 inHg
2.4 hPa|mbar
0.03 PSI
0.01 inHg
0.1 hPa|mbar
0.01 PSI
Refer to Ranges for Sensors Employed Pressure
User Input (Reference Altitude)
Air pressure that would be present in identical conditions at MSL. Station pressure compensated for local elevation provided by reference altitude. Requires accurate reference altitude to produce maximum absolute accuracy.
Crosswind &
Headwind/Tailwind
                      7.1% 1 mph
1 ft/min
0.1 km/h
0.1 m/s
0.1 knots
Refer to Ranges for Sensors Employed Wind Speed
Compass
Effective wind relative to a target or travel direction. Auto-switching headwind/tailwind indication.
Delta T                         3.2 °F
1.8 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Difference between dry bulb temperature and wet bulb temperature. When spraying, indicates evaporation rate and droplet lifetime. Safe range for pesticide spraying is 4 to 16 °F / 2 to 9 °C.
Density Altitude             226 ft
69 m
1 ft
1 m
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Local air density converted to equivalent elevation above sea level in a uniform layer consisting of the International Standard Atmosphere.
Dewpoint       3.4 °F
1.9 °C
0.1 °F
0.1 °C
15 to 95 % RH Refer to Range for Temperature Sensor Temperature
Relative Humidity
Temperature that a volume of air must be cooled to at constant pressure for the water vapor present to condense into dew and form on a solid surface. Can also be considered to be the water-to-air saturation temperature.
Evaporation Rate                         0.01 lb/ft2/hr
0.06 kg/m2/hr
0.01 b/ft2/hr
0.01 kg/m
2/hr
Refer to Ranges for Sensors Employed Wind Speed
Temperature
Relative Humidity
Pressure
User Input (Concrete Temperature)
The rate at which moisture is lost from the surface of curing concrete. Requires user measurement and entry of concrete temperature obtained with an accurate IR or probe thermometer (°F or °C, not included). Readings should be taken 20 inches above pour surface with the thermistor shaded, and averaged for 6-10 seconds using built-in averaging function.
Heat Index       7.1 °F
4.0 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Perceived temperature resulting from the combined effect of temperature and relative humidity. Calculated based on NWS Heat Index (HI) tables. Measurement range limited by extent of published tables.
Moisture Content |
Humidity Ratio ("Grains")
                      .3 gpp .04 g/kg 0.1 gpp
0.01 g/kg
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Mass of water vapor in a mass of air.
Relative Air Density                         0.3% 0.1% Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
The ratio, expressed as a percentage, of measured air density to the air density of a standard atmosphere as defined by the ICAO.
Thermal Work Limit (TWL)                         10.9 W/m2 0.1 W/m2 Refer to Ranges for Sensors Employed Wind Speed
Temperature
Globe Temperature
Relative Humidity
Pressure
Estimated safe maximum continuously sustainable human metabolic rate (W/m2) for the conditions and clothing factors. Based off of estimated metabolic output of typical human. On-screen zone warnings.
Outdoor Wet Bulb Globe Temperature
(WBGT)
                        1.3 °F
0.7 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Wind Speed
Temperature
Globe Temperature
Relative Humidity
Pressure
Measure of human heat stress defined as the combination of effects due to radiation, convection, and conduction. Outdoor WBGT is calculated from a weighted sum of natural wet bulb (Tnwb), globe temperature (Tg), and dry bulb temperature (Td). User settable on-screen warning zones.
Wet Bulb Temperature - Naturally Aspirated (Tnwb)                         1.4 °F
0.8 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Wind Speed
Temperature
Globe Temperature
Relative Humidity
Pressure
Similar to psychrometric wet-bulb temperature (see below). However, Tnwb only undergoes forced convection from the ambient air velocity. Tnwb is a measure of the evaporative cooling that the air will allow. This is accounted for by combining the effects of, mainly, relative humidity and windspeed.
Wet Bulb Temperature - Psychrometric         3.2 °F
1.8 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Temperature indicated by a sling psychrometer. Due to nature of the psychrometric ratio for a water-air system, this approximates the thermodynamic wet-bulb temperature. The thermodynamic wet-bulb temperature is the temperature a parcel of air would have if cooled adiabatically to saturation temperature via water evaporating into it.
Wind Chill     1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Wind Speed
Temperature
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. Measurement range limited by extent of published tables.
ADDITIONAL SPECIFICATIONS
Display & Backlight                     Reflective 3 1/2 digit LCD. Digit height 0.36 in / 9 mm. Aviation green electroluminescent backlight. Manual activation with auto-off.
                    Reflective 5 digit LCD. Digit height 0.36 in / 9 mm. Choice of aviation green or visible red (NV models only) electroluminescent backlight. Manual activation with auto-off.
            Multifunction, multi-digit monochrome dot-matrix display. Choice of aviation green or visible red (NV models only) electroluminescent backlight. Automatic or manual activation.
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.
Max/Avg Wind               One-button clear and restart of Max Wind Gust and Average Wind measurement.
            Max and average wind calculation may be started and stopped independently of data logging of other values, along with all other wind-related functions: air velocity, crosswind, headwind/tailwind, wind chill, WBGT, TWL, evaporation rate.
Data Storage & Graphical Display, Min/Max/Avg History            
4000
points

3200
points

3200
points

3600
points

2300
points

2900
points

2500
points
Minimum, maximum, average and logged history stored and displayed for every measured value. Large capacity data logger with graphical display. Manual and auto data storage. Min/Max/Avg history may be reset independently. Auto-store interval settable from 2 seconds to 12 hours, overwrite on or off. Logs even when display off except for 2 and 5 second intervals (code version 4.18 and later). Data capacity shown.
Data Upload & Bluetooth® Data Connect Option             Requires optional PC interface (USB or RS-232) or Bluetooth data transfer option and provided software.
Bluetooth Data Transfer Option: Adjustable power consumption and radio range from up to 30 ft | 9 meters. Individual unit ID and 4-digit PIN code preprogrammed for easy identification and data security when pairing and transmitting. Employs Bluetooth Serial Port Protocol for data transmission.
Clock / Calendar               Real-time hours:minutes clock.
            Real-time hours:minutes:seconds clock, calendar, automatic leap-year adjustment.
Auto Shutdown               After 45 minutes of no key presses.
            User-selectable -- 15 or 60 minutes with no key presses or disabled.
Languages             English, French, German, Italian, Spanish.
Certifications CE certified, RoHS and WEEE compliant. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge).
Origin Designed and manufactured in the USA from US and imported components. Complies with Regional Value Content and Tariff Code Transformation requirements for NAFTA Preference Criterion B.
Battery Life               CR2032, one, included. Average life, 300 hours. Battery life reduced by backlight use in 2000 to 3500 models.
            Standard Models: AAA Alkaline, two, included. Average life, 400 hours of use, reduced by backlight or Bluetooth radio transmission use.
Tactical Models: AAA Lithium, two, included. Average life, 400 hours of use, reduced by backlight or Bluetooth radio transmission use.
Shock Resistance MIL-STD-810g, Transit Shock, Method 516.5 Procedure IV; unit only; impact may damage replaceable impeller.
Sealing Waterproof (IP67 and NEMA-6).
Operational Temperature Limits 14° F to 131° F | -10 °C to 55 °C Measurements may be taken beyond the limits of the operational temperature range of the display and batteries by maintaining the unit within the operational range and exposing it to the more extreme environment for the minimum time necessary to take reading.
Storage Temperature -22.0 °F to 140.0 °F | -30.0 °C to 60.0 °C
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).
              5.0 x 1.8 x 1.1 in / 12.7 x 4.5 x 2.8 cm, 3.6 oz / 102 g.
                        6.5 x 2.3 x 1.1 in / 16.5 x 5.9 x 2.8 cm, 4.4 oz / 125 g.
* NOTE: Accuracy calculated as uncertainty of the measurement derived from statistical analysis considering the comined effects from primary sensor specifications, circuit conversions, and all other sources of error using a coverage factor of k=2, or two standard deviations (2Σ).
Please note, these specifications are valid for all Kestrel 4400 products and all other Kestrel 4000 series with a serial number higher than 659340. If your product has a lower serial number, please reference the previous version of the specifications.
© June 2012 Nielsen-Kellerman | 21 Creek Circle Boothwyn PA 19061 USA | www.NKhome.com                    

Full Kestrel Specifications PDF
English (40.3 KB) | French (25.8 KB) | German (23.8 KB) | Italian (24.7 KB) | Portuguese (25.1 KB) | Spanish (24.9 KB)

 

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