
We sent a meteorologist from our team to Boothwyn, Pennsylvania where Nielsen-Kellerman is headquartered. There, the 90-employee company created by engineers Richard Kellerman and Paul Nielsen designs, manufacturers, and distributes rugged, waterproof environmental and sports performance instruments.
In the weather community, they are most famous for their Kestrel brand of pocket anemometers. An anemometer is a device used for measuring wind speed. The term is derived from the Greek word anemos, which means wind, and is used to describe any wind speed measurement instrument used in meteorology. The Kestrel devices provide a variety of measurements including wind speed and direction; one device can even measure wet bulb globe temperature readings, alarming the user of the dangers of heat stress and heat illness. Before developing these sophisticated weather devices, Nielsen-Kellerman had a rich history helping other outdoor enthusiasts.

Richard Kellerman, a chemist at Xerox Inc., was also an avid long distance runner. In 1978, Kellerman crossed paths with Theodore “Ted” Nash, an American competition rower, Olympic champion, and rowing coach. Coach Nash asked Kellerman to develop a product that would simplify the coxswain’s job on the water. A coxswain is the leader in a competitive rowing shell; in addition to following the orders of the team coach, the coxswain is connected to the way the shell feels, what’s working, what needs to be changed, and how. A successful coxswain must keep track of the drill, time, pace, feel of the boat, direction of the boat, and safety. During a race, a coxswain is responsible for steering, calling the moves, and responding to the way the other boats are moving.
With the collaboration of fellow Xerox employee Paul Nielsen, they developed a device to combine the tasks of an amplifier, stroke meter and timer to simplify the coxswain’s job. Calling the device a CoxBox, the product was an instant hit for the rowing community and Nielsen-Kellerman was founded.

In the early 1980s, Nielsen-Kellerman expanded their product line to include the original StrokeCoach stroke meter, designed for scullers and straight boats so that they, too, could know their stroke rate and time. Soon after, Nielsen-Kellerman unveiled the Chronostroke for rowing coaches and developed and manufactured the original monitor for the Concept II rowing machine. With a robust product line-up, the company moved into an old rayon-making factory in Marcus Hook, Pennsylvania. Eventually the company launched the Pace Coach and SpeedCoach products, becoming a large player in a market that served audio equipment, performance monitors, and stop-watches to rowers.
But by the early 90s Nielsen-Kellerman felt the need to expand beyond rowing. In 1996, the company unveiled the Kestrel 1000, the company’s first foray into meteorological devices. Being able to develop accurate and dependable meteorological devices isn’t easy; Nielsen-Kellerman used innovative approaches to perfect their device. Using a wind tunnel they built, Nielsen-Kellerman developed a special vane and flat-stamped aluminum impeller blades for durability and accuracy. The wind surfaces were anodized so they wouldn’t rust

in the elements. The device is engineered to take measurements in a raging rain storm and handle winds up to 135mph, which is on the low end of a Saffir-Simpson Hurricane wind scale Category 4 storm. This aluminum impeller was later replaced by a precision molded impeller, further improving the repeatability of manufacture and performance.
With the success of the rowing products and its first weather device, Nielsen-Kellerman moved again, this time to a new plant in Chester, Pennsylvania. The company, which is proud to create Made-in-America products, remained in Chester until 2004; due to growth of the organization, they moved to their larger modern-day facility in Boothwyn, Pennsylvania.
In 1997, the Kestrel 2000 arrived with an added feature of measuring temperature. Beyond measuring things such as current wind speed, maximum wind gust, and average wind speed, this new meter also measures air, water, and snow temperature as well as wind chill. Later, the Kestrel 2500 would add atmospheric pressure readings to the device.
Nielsen-Kellerman eventually added a hygrometer to their anemometers beginning with the launch of the Kestrel 3000. A hygrometer is an instrument used for measuring the moisture content in the atmosphere. Humidity measurement instruments usually rely on measurements of some other quantity such as temperature, pressure, mass or a mechanical or electrical change in a substance as moisture is absorbed. In the case of the Kestrel 3000, electronics help measure the moisture content and report relative humidity.

Michael Naughton, Director of Product Management, told us, “Phones started ringing off the hook with the release of the Kestrel 3000.” Unlike previous outdoor enthusiasts that were using the anemometers, Naughton told us that there was significant interest in the device from military and first responder customers. “These customers wanted to know conditions on the human body. Because of that, we created a WBGT sensor to measure wet bulb globe temperature.” Wet Bulb Globe Temperature is a measure of the heat stress in direct sunlight, which takes into account the temperature, humidity, wind speed, sun angle and cloud cover/solar radiation. This differs from the heat index, which takes into consideration temperature and humidity and is calculated for a shady area. These metrics can be very important to people wearing military or firefighting uniforms and/or those carrying rescue equipment and/or emergency supplies. They can also be important to everyday athletes and outdoors people; understanding heat stress could reduce the risk of heat-related injuries everywhere from football fields to tennis courts. With this interest, Nielsen-Kellerman introduced the Kestrel 4600 which introduced a small 1” black globe above the wind measuring device to help calculate heat stress.

Over time, Nielsen-Kellerman added additional bells and whistles to their high-end Kestrel device. In 2001, the 4000 model used a graphic display which featured logged memory; a wired interface allowed the device to download data to computers. In 2007, a compass was added to the 4500 model. In 2010, Bluetooth technology was added to some anemometers so data could be transmitted to other nearby devices; in 2015, the 4000 series were redesigned and allowed for better Bluetooth integration into mobile devices.
Nielsen-Kellerman created Kestrel devices for unique audiences. The Kestrel Advanced 5000 includes pressure and humidity but offers no compass. The Kestrel 5100 is designed for racing applications while the Kestrel 5200 provides technical insights for professionals such as air conditioning technicians or concrete finishers pouring concrete. The Kestrel 5400 includes the WBGT sensor for heat stress tracking while the Kestrel 5500 adds a compass. The Kestrel 5700 series is designed for ballistics customers.
Committed to the ballistics space, Nielsen-Kellerman partnered with Applied Ballistics and Horus to develop special devices for military and gun enthusiast customers. Ballistics is the science of mechanics that deals with the launching, flight, behavior, and effects of projectiles, especially bullets. Ballistics calculations depend on three primary data sets: what’s happening in the environment a shot is taking place in, the gun/round that’s being shot, and the distance/angle to the target. While the user enters gun/round and target information into the device, the Kestrel 5700 takes into consideration atmospheric measurements in real-time to provide the shooter with accurate information to take the guess-work out of long-distance shots.

Beyond the line built around an anemometer, Nielsen-Kellerman also created a product line-up known as the Kestrel DROP in 2013. Shaped almost like a raindrop, the small key-fob sized devices are rugged, accurate environmental data loggers. There are five Kestrel DROP models, with D1 offering temperature readings and D3FW (FW stands for Fire Weather), their fifth, also adding humidity, heat index, dew point temperature, station pressure, density altitude, pressure trend, and wet bulb temperatures. Models D2 and D3 offer just some of those features. Regardless of DROP model, all connect to an iOS or Android device with Bluetooth. Users can even export the data captured by the DROP in a Comma Separated .CSV file. Whether you’re a camper curious about the conditions at your campsite, monitoring conditions in a wine cellar or cigar humidor, or in the fulfillment business tracking the environmental conditions around your delivery, these devices provide robust meteorological insights through an extremely compact set of sensors.
While Nielsen and Kellerman sold to private investors in 2010, Alix James, the stepdaughter of co-founder Richard Kellerman, remains at the helm of the company as CEO. She’s literally grown up with the company, having soldered CoxBoxes and painted the original cans used in the company’s original rowing products in her youth. The company motto is on display prominently at the factory: “Nielsen-Kellerman is committed to providing the best experience for our customers by immersing ourselves in each market we serve to design and manufacture rugged, reliable products that solve real-world problems in the most challenging environments.” She and four people in product management are looking forward to the future, exploring new specific markets to explore, developing custom solutions for niche markets, developing apps for the future, and incorporating data cloud solutions. Beyond improving their product line-up, they’re also looking for ways to make the world a better place. In addition to using green business practices in their plant operations, Nielsen-Kellerman donates over 2% of their pretax profits to charitable organizations that they believe are helping make the world a better place in ways relevant to their business and their customers.
People can purchase Nielsen-Kellerman products through their website, Amazon, or through one of more than 400 distributors worldwide.