Kestrel 3500NV Weather Meter with Night Vision

$209.00

Split second decisions in the field leave no time for guesswork. Get every environmental condition in seconds.

Availability: In stock
SKU
0835NV
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Kestrel 3500NV Weather Meter with Night Vision Overview


Environmental Measures
Altitude (Barometric)
Barometric Pressure
Dew Point Temperature
Heat Stress Index
Relative Humidity
Temperature
Wet Bulb Temperature (Psychrometric)
Wind Chill
Wind Speed/Air Speed
Tips For Taking Accurate Measurements

Quickly changing weather conditions require constant, immediate updates. Measure wind speed, temperature, relative humidity, dew point and wet bulb temperature with ONE instrument. Many Kestrel users need to know everything that the weather is doing, but don’t need to log the data. At the press of a button, get all the relevant conditions you need to enable yourself to shift strategies, reduce risk and ensure safety. While the weather can dictate the comfort level of individuals working or playing outside, it plays an even bigger part in many professionals’ jobs. Irrigation professionals use the Kestrel 3500 to ensure they are irrigating efficiently and the water they are dispersing is actually hitting their intended target, and not evaporating or blowing away. On construction sites Kestrel users are preventing plastic shrinkage cracks and curing concrete more effectively with their Kestrel 3500.

Note: The Kestrel 3500NV 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 Weather & Environmental Meters are designed & manufactured in the U.S.A and are backed by our 5-year warranty. Innovatively designed for stability and accuracy in abrupt condition changes. Rugged and durable, Kestrels are drop tested, waterproof and designed to float if dropped in water.

Engraving Note: Please make sure that everything is spelled correctly, as your engraved product cannot be returned. All sales are final on engraved products. Add 2 business days to all engraving orders.

  • 3-Button Control
  • Backlight - Night Vision Preserving Light Red
  • Data Hold Function
  • Date & Time
  • Drop-Tested to MIL-STD-810G
  • Field Humidity Calibration/Correction Routine
  • Hard Slip-On Protective Cover
  • High Contrast, Sunlight Readable Monochrome LCD Display
  • Minimum/Maximum/Average Reading
  • Pressure Sensor
  • Relative Humidity Sensor
  • Temperature Sensor (Patented External Isolated)
  • Waterproof to IP67 (3'/1M for 30 minutes)
  • Battery - 1 x CR2032
  • Certificate Of Conformity (Spec Sheet)
  • Instructions
  • Lanyard
  • Protective Cover - Hard Slip-on

Support Documents for all Kestrels

Replacing the Kestrel Impeller

Product Safety and Warranty Kestrel 5000 Series

Kestrel Basic (1000-3500) Certificates of Comformity

Certificate of Conformity for the Kestrel 1000-3500DT with SNs above 2262687

EMC DECLARATION OF CONFORMITY 2500, 2500NV, 3500, 3500NV

Kestrel 5 Series Troubleshooting Documents

Here is guidance on how to submit an order through the website for Tax Exempt customers.

Kestrel Basic (1000-3500) Instruction Manuals

User Guide for the Kestrel 1000, 2000, 2500, 2500NV, 3000, 3500, 3500NV, 3500DT, and 3500FW

Product Questions

"All measurements not available in all units"

Temperature Functions

For best accuracy when taking temperature measurements you must keep the air moving around the temperature sensor and keep the Kestrel out of prolonged, direct sunlight. If there is a strong breeze, just point the Kestrel into the wind. If there is no wind, swing the Kestrel around in a circle on its lanyard or rapidly wave it back and forth in hand. This ensures that the sensor measures the temperature of the air rather than the temperature of the case. Alternatively, if you have time, allow the Kestrel to rest where you want to measure the air temperature (NOT in your hand or in direct sunlight if there is no wind) until the case temperature equalizes with the air temperature. When equalized, the display will read a constant value. Be aware that this could take a few minutes, particularly if there is no wind.

Humidity Functions

One reason your Kestrel may not be reading accurate ambient humidity is because of proximity to humidity sources such as your hand, your body or the ground. Avoid covering the large humidity chamber opening on the case rear with your fingers. Keep all fingers below the finger groove and away from the chamber opening. Do not take reading that rely upon humidity with the Kestrel meter lying flat – raise it into the air vertically or stand it on its base and orient it into the wind or air flow. If a high level of accuracy is required for measurements involving humidity, do not hold the unit while taking measurements. Taking readings with the Kestrel in your hand or over your body can raise relative humidity by 5% or more. A Kestrel vane mount will isolate the Kestrel Meter from erroneous humidity influences and keep it oriented into the wind or air flow while taking measurements. Whenever you move your Kestrel Meter into a new environment wait until the primary sensor values have stabilized (Temperature, Humidity, etc.) before taking measurements that rely upon these values. After a large change in environmental condition, this may take 15 minutes or more, with humidity potentially taking the longest. If the humidity sensor housing (located above the rear label) is wet, the Kestrel cannot take an accurate humidity reading. If the sensor does become wet, shake the unit vigorously to remove the water, and then let it dry completely before use. If the sensor comes in contact with salt water, rinse it thoroughly with clean water, then shake it and allow it to dry. As is typical with humidity sensors, it is possible for the humidity sensor in the Kestrel to drift over time as described in the spec sheet. If your unit has a Humidity recalibration function, it can be returned to the factory or used with the Kestrel RH Calibration Kit to recalibrate its humidity readings.

Wind Meter Functions

Wind speed is highly dependent on surrounding obstructions such as buildings, yourself and the ground, with wind speeding up as it flows around and over obstacles and slowing down as it passes behind them. Even in an open area, Wind speed will be slower near the ground so ensure you are taking measurements at an appropriate height for your application. Hold the back of the unit directly into the wind. Holding the unit off-axis by 5° will reduce accuracy by 1%, 10° will reduce accuracy by 2% and 15° will reduce accuracy by 3%. Using a Kestrel Vane Mount will ensure the unit is correctly oriented into the wind and measuring accurate wind speeds. The Kestrel impeller housing can rotate in the unit. For best accuracy, ensure one of the three “arms” of the impeller housing is pointing straight up. The wind speed displayed by the Kestrel Meter is a 3 second rolling average. This allows the unit to provide a value that is more representative of the typical, ambient conditions but not capture peak speeds for instantaneous blasts of air.

Compass Functions

The compass in the Kestrel Meter is used for direction, crosswind, headwind/tailwind as well as for capturing various user inputs based on direction. When calibrating and when using the compass, it is important to hold the unit as vertically as possible. Any tilt in angle present when the unit is calibrated or when measurements are taken will negatively impact the accuracy of the compass reading. Many users will inadvertently tilt the Kestrel Meter away from themselves slightly when holding the unit. If a high level of accuracy is required, using a Kestrel vane mount on a leveled tripod for calibration and measurement can eliminate error.

Pressure Functions

All pressure and altitude measurements are made using the pressure sensor. Some units have a dedicated “Pressure” screen which shows Station Pressure, the raw pressure reading straight from the sensor. The Barometric Pressure measurement (Baro) displays the local Barometric Pressure using the Station Pressure measurement adjusted to the local altitude using the Reference Altitude value input by the user. The Altitude measurement displays the local altitude using the Station Pressure measurement combined with the Reference Baro value input by the user. To obtain an accurate barometric pressure or altitude readings, you must first know EITHER your location’s current barometric pressure OR your current altitude. If the Reference Altitude value is incorrect, the Barometric Pressure reading will also be incorrect. If the Reference Barometric pressure value is incorrect, the Altitude reading will also be incorrect. Because Barometric Pressure and Altitude are each dependent on the alternate reference value remaining constant, Barometric Pressure and Altitude cannot be accurately measured simultaneously. If your unit has a pressure recalibration function, a new Barometric Pressure calibration value may be input. If this value was not taken from a verified source (a local airport or weather station) with the Kestrel being calibrated at the same location as the reference device, pressure related measurements may be incorrect.

WBGT

When changing environments (such as moving form an air conditioned room to outdoors or removing the unit from your pocket) the unit requires between 8-15 minutes to equilibrate to its surroundings before taking readings. Take measurements at least 3 feet off the ground and in the same wind or air flow conditions as the people you are monitoring. Ensure the Kestrel is oriented into the wind and able to measure the full wind value. A tripod or pole mount and the Kestrel Rotating Vane Mount are ideal for ensuring accurate measurements. Differences in the reflectivity of ground surfaces such as grass or asphalt will impact measurements. Be sure to take measurements in the same solar/radiant heat environment as the people you are monitoring. Unlike best practices for other measurements, WBGT is intended to be taken in direct sunlight. As long as there is occasional wind the Kestrel has software that allows it to maintain an accurate WBGT reading despite being placed in direct sunlight.

Air Flow

Kestrel Professional Meters can calculate air flow through a duct by combining user input information about the size and shape of the duct with the measured air velocity. In addition to reading the instantaneous Air Flow off the main measurement screen, a more accurate result may be obtained by capturing an average air flow on the Min/Ave/Max screen while traversing the duct. Traversing consists of dividing the area of the duct into evenly sized sections and averaging the air flows at the center of all sections. By spending an equal amount of time at each measurement location and quickly moving between measurement locations, the average air flow measurement can provide a more accurate measure of the air flow in the duct. Capturing an average can be particularly helpful when measuring ducts with registers or dimensionally uneven air flow.

Air Flow Diagram

Evaporation Rate

(Kestrel 5200 Professional Environmental Meter) Kestrel Professional Meters can calculate a concrete evaporation rate (ACI 308) by combining a user input concrete temperature with measured air temperature, wind speed and relative humidity. Concrete mix temperature is generally measured with a probe or infrared thermometer and should be read at the time of making the evaporation rate measurement After inputting the mix temperature, hold the unit vertically, approximately 20 inches above the surface of the concrete while facing the rear of the unit directly into the wind. To avoid inaccurate Evaporation Rate readings due to thermal loading it is best to shade the Kestrel. (Be sure the source of shade is not obstructing the wind speed measurement.) The ACI recommends taking a 6-10 second average of the evaporation rate to account for fluctuating wind speeds. To measure an average Evaporation Rate, scroll right from the Evaporation Current Measurement Screen to the Min/Ave/Max Screen and press select to manually start and stop a capture.

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Yes. You can always trade-in an older Kestrel, regardless of its condition, by using our Customer Trade-In Program.

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  1. Start with a known; either current barometric pressure or current altitude. (NK recommends identifying your current altitude since it is constant.)
  2. Enter this reference altitude on the barometric pressure screen.
    • For K1000-K3500 you would enter this by pressing both outside buttons.
  3. Take note of the updated barometric pressure that is shown.
  4. Use this updated barometric pressure as your reference pressure on the altitude screen.
  5. Now your barometric pressure and altitude are set for your current location/conditions. Important note: If you change altitude the barometric pressure will become inaccurate. If a weather system moves in, the altitude will become inaccurate.

For more info check out our YouTube video on Setting Reference Pressure and Reference Altitude on the Kestrel 4000 series!

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