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Home > Products > Kestrel Hand-held Weather Meters > Kestrel 4250 > Specification
Kestrel 4250 data sheet - download PDF
| Physical | Dimensions | 126mm x 45mm x 29mm | |
| Weight | 102g | ||
| Lanyards | 0.2m and 0.5m (for wrist and neck) | ||
| Case colour | Safety orange | ||
| Display | Display type | Dot matrix LCD with electro-luminescent backlighting | |
| Display update | 1 second | ||
| Data logging | Programmable 2 second to 12 hour intervals, 2000 data points and optional PC upload | ||
| Functions | Wind speed (current, maximum and average) | ||
| Temperature | |||
| Relative Humidity | |||
| Moisture content / humidity ratio / water grains | |||
| Calculated Dew Point | |||
| Station pressure | |||
| Barometric pressure | |||
| Air density | |||
| Relative air density | |||
| Density altitude | |||
| Altitude | |||
| Wind chill | |||
| Heat index | |||
| Wet bulb temperature | |||
| Speed units | kt, m/s, km/h, mph, ft/min, Beaufort Force (B) | ||
| Temperature units | ºC, ºF | ||
| Pressure units | mbar, inHg, hPa, psi | ||
| Density altitude units | m, ft | ||
| Air density units | kg/m3, lb/ft3 | ||
| Relative air density units | % | ||
| Moisture content / humidity ratio units | g/kg, gpp | ||
| Altitude units | m, ft | ||
| Date and time display | dd/mm/yy, mm/dd/yy, 12 hour, 24 hour | ||
| Performance | Speed (1 sec response) |
Operational range | 0.4m/s to 60m/s (0.8 to 135.0mph) |
| Specification range | 0.4m/s to 40m/s (0.8 to 89.0mph) | ||
| On axis accuracy | ± 3% of reading or ± 0.1 m/s. (Some loss of accuracy from bearing wear may occur with sustained operation at or near maximum speed) | ||
| Off-axis response | -1% @ 5°, -2% @ 10°, -3% at 15° | ||
| Calibration drift | <2% after 100hrs operation at 7m/s |
||
| Resolution | 0.1 kt, m/s, km/h, mph. 1 FPM below 1999 FPM, 10 FPM above 2000 FPM. 1 Beaufort (0 to 12) | ||
| Temperature (1 sec response) |
Operational range | -45.0ºC to +125.0ºC | |
| Specification range | -29.0ºC to +70.0ºC | ||
| Accuracy | ±1ºC | ||
| Resolution | 0.1º | ||
| Wind chill accuracy | ±1.0ºC (from wind speed and temperature) | ||
| Relative Humidity (1 min response) |
Operational range | 0% to 100% | |
| Specification range | 5% to 95% non-condensing | ||
| Resolution | 0.1% | ||
| Accuracy | ±3% (when unit allowed to equilibrate to external temperature) | ||
| Calibration drift | ±2% over 24 months (correctable) | ||
| Heat index accuracy | ±2ºC (between 21.1ºC and 54.4ºC) | ||
| Dew point accuracy | ±2ºC (above 20% relative humidity) | ||
| Pressure (1 sec response) |
Operational range | 10 to 1100 mbar at 25ºC | |
| Specification range | 750 to 1100 mbar at 25ºC | ||
| Resolution | 0.1 mbar | ||
| Accuracy | ±3 mbar (from -10ºC to 60ºC) | ||
| Calibration drift | Typically ±1 mbar per year (correctable) | ||
| Wet bulb temperature accuracy | ±2ºC (between 0ºC and 37.8ºC) | ||
| Density altitude accuracy | ±75m (between 0ºC and 37.8ºC) | ||
| Air density accuracy | ±2% (between 0ºC and 70ºC) | ||
| Moisture content accuracy | 10% (Typical between -29ºC and 54ºC) | ||
| Altitude (1 sec response) |
Operational range | -2000m to +9000m (-6000 ft to +30,000 ft) | |
| Specification range | -2000m to +6000m at 25ºC | ||
| Accuracy | ±15m (max error out of spec range: ±30m) | ||
| Resolution | 1m or 1ft | ||
| Sensors | Impeller | Diameter 25mm High precision axle and jewel (sapphire) bearings User replaceable impeller assembly |
|
| Temperature | Hermetically sealed precision thermistor | ||
| Relative Humidity | Polymer capacitive sensor, mounted externally in thin-walled chamber | ||
| Pressure | Monolithic piezo-resistive silicon based sensor with second order temperature correction | ||
| Environmental | Sealing | Electronics enclosure IP67 [Water resistant] | |
| Shock | Drop tested (MIL.STD.810F - unit only) | ||
| Temperature | Operating range: -10ºC to +55ºC (operation
over a wider range is possible with reduced display readability) Storage range: -30ºC to +60ºC |
||
| EMC | CE marked | ||
| Miscellaneous | Battery | 2 AAA alkaline, user replaceable | |
| Battery Life | 400 hours of use, average, ± depending on backlight use | ||
| Auto switch off | Selectable to remain switched on, switch off 15 minutes or 60 minutes after last key press | ||
| Wind chill equivalent temperature calculation | Utilises the (US) NWS Wind Chill Temperature (WCT) Index, revised 2001, with wind speed adjusted by a factor of 1.5 to yield equivalent results for wind speed measured at 10m above ground | ||
| Heat Index calculation | Steadman, from temperature and relative humidity | ||
| Certification | Wind speed, temperature, humidity and
pressure measurements are tested during
manufacture. A certificate of conformity (C of C) is included with each Kestrel. Calibration certificates are available for an additional fee. |
||
| Guarantee | 5 years | ||
| The manufactures reserve the right to amend the specification and therefore the information in this document may be subject to change | |||
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