Kestrel®
RH Calibration KitEach Kestrel Pocket weather Meter is individually calibrated after assembly. In essence, each unit is "taught" what the correct relative humidity (RH) values should be for given signals from the RH sensor.
NK calibrates at RH=32.8% and RH=75.3%. Calibration is done in two sealed environmental chambers maintained at 25°C. The humidity is held constant with saturated aqueous salt baths: magnesium chloride for the RH 32.8% chamber and sodium chloride for the 75.3% chamber. Chamber temperatures are held constant at 25°C ± 0.5°C
The temperature and RH of each chamber is independently monitored using a precision chilled mirror dew point hygrometer (EdgeTech Model 2002) accurate to ± 0.1Cº and NIST (National Institute of Standards and Technology) traceable. A proprietary auto calibration routine controls the calibration process. After 60 minutes this routine stores a calibration value which forces the Kestrel to be correct at the RH value of the chamber.
The response of the humidity sensor is a highly reproducible, non-linear curve. This non-linear characteristic is stored in the microprocessor used to compute RH, and in this manner we are able to maintain an accuracy of ± 3% of scale over the relative range 5% - 95%.
Field Calibration
The Kestrel should be recalibrated if the RH sensor has been replaced or has shown drift in its RH measurement. Field calibration requires the use of the RH Calibration Kit. For instructions related to the field calibration procedure, please view the Field Calibration Kit Manual. This manual explains in detail all of the steps for recalibrating your Kestrel. This process will take approximately 13 hours, including setup and calibration.
Contents of the RH Calibration Kit
The RH calibration kit includes the following items:
- three clear, sealable containers
- one container with magnesium chloride solution
- one container with sodium chloride solution
- two wooden scrapers
- an insulated carrying case to hold all of the above and maintain a stable environment while performing calibration
The large container is used to create a stable environment. The
small containers are used to hold the saturated salt solution. The saturated
salt solutions generate well-defined humidities when they are confined to a
contained environment.
Part #271510120
New for Spring 2008! A tripod fitted with the same Kestrel friendly clamp as on our mini tripod. Will accommodate any Kestrel model. Or remove the clamp to attach the Vane Mount. The 5 section twist and pull assembly extends to 51" and collapses to a mere 14". Weighing only 1.7 pounds, this tripod is the perfect companion on any trip!
Part #271510124
Clamp any Kestrel into this sturdy but lightweight tripod to take readings in the field. The tripod’s legs extend to permit a maximum height of 10", and a minimum of 6". Ultra-compact and portable, it folds to just 7.5" and weighs 4.8 oz. For further options, the top clamp detaches and is compatible with any tripod with a standard tripod mount (1/4" 20 thread fitting). Comes with a padded carry pouch.
Part #271510126
The Kestrel Portable Vane Mount is an ingeniously simple accessory designed for extreme light weight and portability. The Vane Mount assembles in seconds and the precision pivot and lightweight vane extension allows the unit to spin freely in the slightest of breezes. The incorporated level ensures that the Vane Mount is installed correctly and that direction readings will be accurate.
The Vane Mount is compatible with all Kestrel models. And paired with the Kestrel's 2000 data-point memory log, extensive data can be collected including wind speed and direction.
Together, the Kestrel 4500 and Vane Mount weigh less than 8 ounces (227 g.) and pack into a compact 2 x 6 inches (5 x 15.25 cm) case, which protects the Vane Mount pieces and Kestrel Meter. The Vane Mount can be affixed to any tripod for a complete weather station you can easily pack into remote locations.
Part #271510122
This sturdy padded nylon case lets you build a Kestrel 4000 Toolkit perfect for your needs and still carry it on your belt with ease. The top flap features a hook/loop closure and a special window designed to keep the Kestrel 4000 sensors continuously exposed to the outside air, ensuring accurate logged readings. The durable elastic loop on the side of the case is perfect for carrying a small flashlight or other tool. No need to find yourself in the field with dead batteries -- an elastic battery loop inside securely holds two backup AAA batteries.
Part #271510128
