Overview
Ensure safety and effectiveness during agricultural spraying with the Kestrel 3500 Delta T.
To ensure safety and effectiveness when spraying, it is critical to measure relative humidity, wind speed and wind direction. Many locales regulate the maximum permitted wind speed during spraying to minimize spray drift. In hot, dry conditions, expensive chemicals may evaporate into the air rather than onto your crops. However, you can minimize costly evaporation by selecting an appropriate nozzle and increasing the spray droplet size.
Quickly & Accurately Calculates Delta T For You
The Kestrel 3500 DT incorporates a Delta T calculation, the spread between the wet bulb temperature and the dry bulb temperature (in degrees C or F). Delta T offers a quick guide to determining acceptable spraying conditions. For example, it is not recommended to apply pesticides when Delta T is above 10 — a range of 2 to 8 is ideal. With the Kestrel 3500 Delta T, the calculation is done for you accurately and simply.
The Kestrel 3500 Delta T incorporates barometric pressure correction in its wet bulb temperature calculation, ensuring accuracy even on low pressure days, at high altitudes, and in very dry weather when Delta T monitoring is important. No other pocket weather meter offers this feature with this level of accuracy.
Kestrel 3500 Delta T Measures
Delta T
Wind speed (current, average, and maximum)
Temperature of air, water & snow in °F or °C
Relative humidity in %
Dewpoint
Barometric pressure
Altitude
Wet bulb temperature
Kestrel 3500 Delta T Features
Real-time clock
Protective cover with sure-grip overmolding
Data hold function
Large easy-to-read display with backlight
Waterproof and floats
Measure environmental conditions quickly and accurately
Forecast weather with pressure trend indicator
Reliable, portable and easy to use
Innovative humidity sensor designed for stability and accuracy in abrupt condition changes
Thermally adjusted humidity sensor
Patented user-replaceable impeller
Quick response, external thermistor
High precision pressure sensor
Humidity sensor can be recalibrated in the field with our Relative Humidity Calibration Kit.
All instruments and accessories are completely assembled in the USA
5-year warranty
Kestrel 3500 Delta T Includes
A slip-on protective cover
Neck lanyard
CR2032 coin cell battery (Average life 300 hours)
Kestrel Certificate of Conformity
Specifications:
| MeasurementResponse Time |
Units |
Operational Range |
Resolution |
Accuracy (+/-) |
|
| Wind Speed1 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 |
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| km/h |
1.0 to 218.0 km/h |
0.1 |
1.0 to 144.0 km/h |
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| mph |
0.8 to 135.0 mph |
1 |
0.8 to 89.0 mph |
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| knots |
0.6 to 118.3 kt |
0.1 |
0.6 to 78.0 kt |
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| Beaufort |
0 to 12 B |
0.1 |
0 to 12 B |
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| 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). |
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| Temperature1 second |
°F |
-49.0 to 257.0 °F |
0.1 |
|
-20.0 to 158.0 °F |
| °C |
-45.0 to 125.0 °C |
0.1 |
|
-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. |
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| Relative Humidity1 minute |
%RH |
0.0 to 100.0 % |
0.1 |
3.0 %RH |
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 relative humidity accuracy, unit must be permitted to equilibrate to external temperature when exposed to large, rapid temperature changes and must be kept out of direct sunlight.) Calibration drift +/- 2% over 24 months. Relative humidity may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802). |
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| Pressure1 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. |
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| Altitude1 second |
ft |
-6000 to 30000 ft |
1 |
|
At 77.0 °F, <19,700 ft. Max error +/- 98 ft |
| m |
-2000 to 9000 m |
1 |
|
At 25.0 °C, <6,000 m. Max error +/- 30 m |
|
| Temperature compensated pressure (barometric) altimeter. |
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| Dewpoint1 minute |
°F |
0.0 to 100.0 %RH, -49.0 to 257.0 °F |
0.1 |
|
-20.0 to 158.0 °F, 20.0 to 95.0% RH |
| °C |
0.0 to 100.0 %RH, -45.0 to 125.0 °C |
0.1 |
|
-29.0 to 70.0 °C, 20.0 to 95.0 %RH |
|
| Calculated from the primary measurements of temperature and relative humidity. Temperature to which the air would need to be cooled at a constant pressure to become saturated. |
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| Wet Bulb Temperature1 minute |
°F |
-49.0 to 257.0 °F, 0.0 to 100.0 %RH, 8.86 to 32.48 inHg |
0.1 |
|
32.0 to 100.0 °F, 5.0 to 95.0% RH, 8.86 to 32.48 inHg, <19700 ft |
| °C |
-45.0 to 125.0 °C, 0.0 to 100.0 %RH, 300.0 to 1100.0 hPa |
0.1 |
|
0.0 to 37.8 °C, 5.0 to 95.0 %RH, -2000.0 to 9000.0 hPa, <6000 m |
|
| Calculated from the primary measurements of temperature, relative humidity and pressure. Temperature indicated by a wet bulb psychrometer. |
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| Max/Avg Wind Speed |
One-button clear and restart of Max Wind Gust and Average Wind measurement. |
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| Pressure Trend |
Continuously updating three-hour barometric pressure trend indicator: rising rapidly, rising, steady, falling, falling rapidly. |
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| Display |
Reflective 4 digit LCD. Digit height 0.36 in / 9 mm. |
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| Display Update |
1 second. |
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| Display Backlight |
Aviation green electroluminescent backlight. |
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| Clock / Calendar |
Real-time hours:minutes clock. |
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| 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. |
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| Storage Temperature |
|
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| Auto Shutdown |
After 45 minutes of no key presses. |
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| Certifications |
CE certified. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge). |
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| Batteries |
CR2032, one, included. Average life, 300 hours of use, +/-depending on backlight use. |
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| Environmental |
Waterproof (IP67 standard). Drop-tested (MIL.STD.810F; unit only. Substantial impact may damage replaceable impeller.). |
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| 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. |
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| Weight |
Unit 2.3 oz / 65 g. Case 1.3 oz / 37 g. |
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| 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. AdditionalNIST Calibration and Certification servicesare available. |
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Producing Area：USA