Kestrel 3550AG Pocket Delta T Crop Spraying Weather Meter

Avoid spray drift with this portable, connected handheld weather meter

$229.00 USD $286.00 USD
Kestrel  |  SKU: 0835AGLCHVG  |  Barcode: 730650004270

Measures

  • Wind Speed
  • Current Wind Speed
  • Average Wind Speed
  • Maximum Wind Gust
  • Temperature
  • Barometric Pressure
  • Relative Humidity
  • Wind Chill
  • Heat Stress Index
  • Dew Point Temperature
  • Wet Bulb Temperature (Psychrometric)
  • Temperature-Humidity Index (THI)
  • Altitude (Barometric)
  • Delta-T
  • Wind Direction
  • Bluetooth

Includes

  • (1) CR2032 Lithium Battery
  • Instructions
  • Lanyard
  • Certificate Of Conformity (Spec Sheet)
  • Protective Cover - Hard Slip-on

Warranty

5 year manufacturers warranty.

US Manufacturing

The entire Kestrel line is designed and built in the USA. No other handheld weather meter is. Some electronic components have to be sourced overseas these days, but Kestrel buys American wherever possible. Kestrel believes US manufacturing is the only way to ensure that every Kestrel will do its job right. Kestrel believes it’s important to do its part to keep manufacturing alive and well in the US.

State Sales Tax Information

State sales tax not charged / collected on orders outside of Pennsylvania

Government / Education Pricing Available

Sensor Specifications

Sensor Specifications

Wind Speed

Units of Measure: mph | kt | B | m/s | ft/min / km/h 
Specification Range:
  • 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*
  • 2-131.2 F/S*
Operational Range:
  • 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*
  • 2-196.9 F/S*
Resolution:
  • 0.1 m/s
  • 1 ft/min
  • 0.1 km/h
  • 0.1 mph
  • 0.1 knots
  • 1 B
Accuracy (+/-): Larger of 3% of reading, least significant digit or 20 ft/min
Notes: 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 (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. *F/S only in Ballistics units. Beaufort not available in Ballistics units.

Ambient Temperature

Units of Measure: Fahrenheit, Celsius
Specification Range:
  • -20.0 to 158.0 °F
  • -29.0 to 70.0 °C
Operational Range:
  • 14.0.0 to 131.0 °F
  • -10.0 to 55.0 °C
Resolution:
  • 0.1 °F
  • 0.1 °C
Accuracy (+/-):
  • 0.9 °F
  • 0.5 °C
Notes: 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.

Pressure

Units of Measure: inHg, hPA, mb
Specification Range:
  • 25°C/ 77°F
  • 750-1100 hPa|mbar
  • 22.15-32.48 inHg
  • 10.88-15.95 PS
Operational Range:
  • 0.30 to 48.87 inHg
  • 10.0 to 1654.7 hPa|mbar
  • 0.14 to 24.00 PSI
  • 14.0 to 131.0 °F -10.0 to 55.0 °C
Resolution:
  • 0.1 hPa|mbar
  • 0.01 inHg
  • 0.01 PSI
Accuracy (+/-):
  • 1.5 hPa|mbar
  • 0.044 inHg
  • 0.022 PSI
Notes: Monolithic silicon piezo-resistive pressure sensor with second-order temperature correction. Between 1100–1600 mbar, unit will operate with reduced accuracy. Sensor may not operate above 1600 mbar and can be damaged above 6,000 mbar or below 10 mbar. Calibration drift is negligible for the life of the product.

Relative Humidity

Units of Measure: %
Specification Range: 5 to 95% 25°C non-condensing
Operational Range: 0 to 100% 
Resolution: 0.1 %RH
Accuracy (+/-): 3%RH
Notes: 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 is typically less than ±0.25% per year.

Calculated Measurements

Wind Chill

Accuracy (+/-):
  • 1.6 °F
  • 0.9 °C
Resolution:
  • 0.1 °F
  • 0.1 °C
Sensors employed:
  • Wind Speed
  • Temperature

Barometric Pressure

Accuracy (+/-):
  • 0.07 inHg
  • 2.4 hPa|mbar
  • 0.03 PSI
Resolution:
  • 0.01 inHg
  • 0.1 hPa|mbar
  • 0.01 PSI
Sensors employed:
  • Pressure
  • User Input (Reference Altitude)

Altitude

Accuracy (+/-):
  • typical: 23.6 ft/7.2 m
  • from 750 to 1100 mBar
  • max: 48.2 ft/14.7 m
  • from 300 to 750 mBar
Resolution:
  • 1ft
  • 1m
Sensors employed:
  • Pressure
  • User Input (Reference Pressure)

Dew Point

Accuracy (+/-):
  • 3.4 °F
  • 1.9 °C
  • 15-95% RH.
  • Refer to Range
    for Temperature Sensor
Resolution:
  • 0.1 °F
  • 0.1 °C
Sensors employed:
  • Temperature
  • Relative Humidity

Wet Bulb Temperature - Psychrometric

Accuracy (+/-):
  • 3.2 °F
  • 1.8 °C
Resolution:
  • 0.1 °F
  • 0.1 °C
Sensors employed:
  • Wind Speed
  • Temperature

Delta T

Accuracy (+/-):
  • 3.2 °F
  • 1.8 °C
Resolution:
  • 0.1 °F
  • 0.1 °C
Sensors employed:
  • Temperature
  • Relative Humidity
  • Pressure

THI (NRC)*

Accuracy (+/-):
  • 1.5 °F
  • 0.8 °C
Resolution:
  • 0.1 °F
  • 0.1 °C
Sensors employed:
  • Temperature
  • Relative Humidity
Notes: * The NRC THI equation is defined as: *THI = (1.8 X Tdb +32) – [(.55 - .0055 X RH) X (1.8 X Tdb-26)] (National Research Council, 1971) where Tdb is dry bulb temperature in °C and RH is relative humidity expressed as a %. This is the equation referenced by Ontario Ministry of Agriculture, Food, and Rural affairs; Journal of Dairy Science; and the University of Arizona. The YOUSEF THI equation is defined as: THI = Tdb + (0.36 × Tdp) + 41.2 (Yousef, 1985) where Tdb is dry bulb temperature in °C and Tdp is dew point temperature in °C. This is the equation referenced by Dairy Australia, University of Missouri, and USDA.

THI (Yousef)*

Accuracy (+/-):
  • 2.3 °F
  • 1.3 °C
Resolution:
  • 0.1 °F
  • 0.1 °C
Sensors employed:
  • Temperature
  • Relative Humidity
Notes: * The NRC THI equation is defined as: *THI = (1.8 X Tdb +32) – [(.55 - .0055 X RH) X (1.8 X Tdb-26)] (National Research Council, 1971) where Tdb is dry bulb temperature in °C and RH is relative humidity expressed as a %. This is the equation referenced by Ontario Ministry of Agriculture, Food, and Rural affairs; Journal of Dairy Science; and the University of Arizona. The YOUSEF THI equation is defined as: THI = Tdb + (0.36 × Tdp) + 41.2 (Yousef, 1985) where Tdb is dry bulb temperature in °C and Tdp is dew point temperature in °C. This is the equation referenced by Dairy Australia, University of Missouri, and USDA.

Downloads:

Description

Kestrel 3550AG Bluetooth Weather Meter for Spray Applications

Spray drift can be hazardous to nearby plants and can also cause harm to livestock, people and wildlife.

With the Kestrel 3550AG, you can keep your crop spraying on-target. With it's Bluetooth connectivity, the Kestrel 3550AG will allow you to log data using a smartphone and the Kestrel app with just a simple click.

No matter the size of your operation -- effective herbicide and pesticide application is critical to your success. Prevent drift, eliminate waste, ensure safety and effectiveness – it all starts with monitoring your conditions.

    Field-Level Environmental Monitoring for Reliable Decision-Making

    It is critical to measure relative humidity, wind speed and wind direction at field-level to minimize waste and maximize safety when spraying. The on-site weather at time of application has a significant impact on the risk of drift. Best management practices include checking weather at the site of application to ensure safe and effective spraying. With a built-in digital compass, the 3550AG measures all relevant environmental conditions for spraying including wind direction.

    Experts urge applicators to take measurements at the field location and make decisions from accurate, onsite information. It’s important to measure wind speed at the height of sprayer booms and not rely on readings from the local airport which could be dozens of miles away. The data from remote weather stations do not accurately reflect the conditions at your specific site.

    "If you face any litigation, they will go to nearest airport and get wind speed there," [if no other record exists] "Airfields are typically flat, so the wind speeds are higher there and taken at heights much greater than the boom height of your sprayer. It’s not unusual to find that the wind speed 20 inches above your crop canopy is 2 to 3 mph slower than a nearby airport’s reading."
    -Dr. Bob Beck, Regional Agronomist at Land O'Lakes

    Validation of current conditions meeting label requirements is every applicator’s priority and should be incorporated into all spraying application decisions. With the Kestrel 3550AG, you can easily monitor real-time weather conditions at the field-level.

    Easy Record Keeping for Peace of Mind with the Free Kestrel App

    As regulations surrounding drift management get tighter and media and public attention continues to increase, the stakes are higher than ever for applicators and farmers when it comes to accountability. It’s imperative to document spray conditions to defend against costly litigation and protect the future of your operation. The Kestrel app makes it easy to do by wirelessly connecting to the 3550 so you're able to view, log, and manage weather data on a mobile device. Now you can document field data right at the time of spray application -- forget pen and paper notes that can get lost or attempting to data log hours after the application when you’re back in the office and likely to forget. With just one click, the Snapshot feature in the app captures and saves an instant record of all live measurements along with a GPS-based timestamp. Conveniently export historical data as valuable documented evidence that you sprayed within acceptable weather conditions.

    Pocket sized, rugged, waterproof, affordable, easy-to-use and equipped with on-unit data logging and wireless data retrieval for monitoring and reporting, the Kestrel 3550AG is your trusted weather guide for spraying and farming.

    The new 3550AG meter has Bluetooth connectivity to pair with the Kestrel app for the ability to wirelessly view, share, and export weather data from a mobile device. Download the Kestrel app from the app store to take advantage of the all the features available. 

    Features:
    • Simple 3-Button Control
    • High Contrast, Sunlight Readable Monochrome LCD Display
    • Backlight (Green)
    • Temperature Sensor (Patented External Isolated)
    • Relative Humidity Sensor
    • CR2032 Coin Cell Battery (Average Life 300 Hours)
    • Data Hold Function
    • Drop-Tested to MIL-STD-810G
    • Waterproof to IP67 (3'/1M for 30 minutes)
    • Kestrel Certificate of Conformity
    • Neck Lanyard
    • Patented Impeller and Sensor Technology
    • Slip-On Protective Cover
    • Time of Day
    • Field Humidity Calibration/Correction Routine
    • User-Replaceable Battery
    • User-Replaceable Impeller
    • Waterproof & Floats
    • Designed and built in the USA

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            Customer Reviews

            Based on 4 reviews
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            C
            Christopher H.

            Bought this Kestrel 3550 AG as an upgrade to the 2500 given for me to use at a previous job. I like that it connects to an app for record keeping and is easily calibrated out in the field. I made this purchase in August after doing a sulfur spray in a sheltered canyon. In November now and it has helped keep the sprays on target.

            L
            Laurent D.

            Everything was perfect, since the order to the shipping. Well done !

            D
            Dominika D.

            I ordered this item for my friend who is in the army. I contacted the store before ordering - the response was quick and very nice. The delivery to Poland was also very fast and the product was well packed.

            M
            Marie J.

            Was very impressed with the whole experience. I live in Ontario, Canada and was a bit skeptical about ordering on line. Ordered my Kestrel. It said 6 day delivery and it was on our door step on day six.Got the unit set up, connected to my phone and am excited to try it next time I spray. To be able to take a snap shot of the weather picture to back up my spray diary is just an extra piece of mind.
            Very happy.

            Kestrel 5500 Weather Meter - ExtremeMeters.com

            Kestrel Instruments

            Quality designed and durably built in the U.S.A. Every Kestrel found in our store is tested for accuracy, includes a full 5 year global factory warranty and comes with a certificate of conformity.