Pair the 4500NV wind meter with Kestrel vane mount and you have a data-logging weather station that sets up in seconds and rotates in the slightest of breezes. Durable? You bet. The 4500NV has been subjected to impact, water submersion, and extreme temperature tests, yet keeps on working. U.S. Special Forces, combat weather teams, firefighters, smoke jumpers, Mt. Everest expeditions, and IRL pit crews are just a few of the people who rely on a Kestrel 4500NV to provide them with the crucial environmental data they need. Watch the Weather Channel during a hurricane and you're sure to spot a Kestrel being wielded by an intrepid on-screen meteorologist.
The major difference between the 4500NV and Kestrel's other weather trackers is the NV's backlight, which incorporates an optical filter to reduce overall brightness and minimize blue and green spectrum light to preserve night vision. Plus, 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 in a soft grayish pink, not red, and is still in the visible spectrum. Note that the NV is not compatible with night-vision equipment.
Why would a user need night-vision protection? In general, 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, however, does not cause this "bleaching out," preventing night blindness and night vision fatigue. The 4500NV is potentially useful for dozens of professions, from wild-land firefighters putting their lives on the line to kite surfers looking for the perfect play conditions. The night-vision line is particularly appropriate for the military, aviators, overnight hikers, professional rescue services, and other personnel who often work in the dark.
The 4500NV offers a number of additional features, including a multifunction three-line display; an automatic and manual data logger; a humidity sensor that can be recalibrated in the field with the Relative Humidity Calibration Kit (sold separately); exterior temperature, humidity, and pressure sensors for fast and accurate readings; graph and recall trends; a flip-top impeller cover that lets you use other functions while still protecting the impeller; and a waterproof, floatable housing. The 4500 NV--which comes with a soft carrying pouch, a neck lanyard, and two AAA batteries--measures 1.8 by 5 by 1.1 inches (W x H x D), weighs only 0.5 pounds, and carries a five-year warranty.
- Heading (true and magnetic)
- Wind direction
- Pressure trend
- Barometric pressure
- Wet bulb temperature
- Relative humidity in percentage
- Heat stress index
- Dew point
- Wet bulb temperature
- Density altitude
- Wind chill
- Air, water, and snow temperature in F or C
- Current, average, and maximum air velocity
Nielsen-Kellerman (NK) was founded in 1978, after Richard Kellerman--a physical chemist at Xerox--was recruited by a crew coach to develop a product that would simplify the coxswain's many jobs on the river. With the collaboration of Xerox associate Paul Nielsen, Kellerman set out to create a unit that combined the tasks of an amplifier, stroke meter, and timer. The Cox Box amplifier idea came to Kellerman after watching a coxswain run his crew into a bridge during a regatta. In 1984, NK expanded its product line to include the original Stroke Coach stroke meter, designed to let scullers and straight boats know their stroke rate and time. Following the success of the Stroke Coach, NK designed the Chronostroke rate and stopwatch for rowing coaches, and developed and manufactured the original monitor for the Concept II rowing machine. In 1996, the company expanded into a completely new product line by launching a line of wind and weather instruments called Kestrel pocket weather meters. In the ensuing years, NK moved into and out of a facility in Chester, Pennsylvania, and eventually landed in Boothwyn, Pennsylvania. The company now specializes in three broad product lines: rowing and sports monitoring instruments, pocket weather meters, and soaring instruments for cross-country soaring pilots.