A little over a month ago, this analysis by John Beamer of HardballTimes.com found it’s way onto Major League Buzz Bot Ballbug.

Beamer began his analysis with this discussion about Detroit’s “faster than a speeding bullet” reliever Joel Zumaya, an explanation of the most commonly used speed gun; the Doppler radar and the factors which determine the calculation of speed;

Radar guns, and their efficacy have always been a hotly debated topic, largely because no one is ever sure how accurate they are. This year the tongue wagging intensified with the emergence of perhaps the hardest thrower ever to step on to a pitching mound: the flame-arm tattooed Joel Zumaya.

In 2006 Zumaya finished with a 1.94 ERA, struck out over 11 per nine innings, and was easily the most dominant,—as well as the most exciting—pitcher in the Tigers pen. Zumaya consistently overpowered hitters with raw pace: Few will ever forget Game 2 of the ALDS, where he left Alex Rodriguez floundering after a volley of 100-plus mph pitches to strike out the side.

Two questions nearly always pervade a discussion about Zumaya. One is whether he is the hardest thrower in the game, and two is how reliable, or unreliable in many cases, radar guns are.

There are many types of radar guns, and all work on a similar principle. Simply put, a radar gun launches a beam of electromagnetic waves at a moving object. On hitting the object the waves are reflected back toward a detector on the gun, which then calculates the speed of the object by analyzing the nature of the reflected beam.

In the major leagues, the most common gun is made by Jugs Company, and is a Doppler radar. A Doppler radar measures speed by detecting minuscule changes in the wavelength of the reflected beam. What does this mean? Imagine a radar gun has fired an electromagnetic wave (e.g., light) toward a moving object. When the wave reaches the object, it is not only reflected but also given an extra “push” by the motion of the object. A slow moving object will “push” less than a fast one. The detector calculates speed by measuring the amount of “push.” In reality, this “push” causes the wavelength of the wave to change—a phenomenon known as the Doppler Effect.

Those of you who recall high school physics may remember that we experience the Doppler Effect on a daily basis, most notably when being passed by a police car or an ambulance with sirens blaring. Police cars have directional sirens, usually stapled to the roof or fender and facing forwards. As the siren approaches, the waves of sound are squeezed together, thereby reducing the wavelength, resulting in a stationery observer hearing a higher pitched sound. When the car passes by, the sound waves from the siren are dragged apart, causing an observer to hear a lower pitch noise.

Another quite cool, but totally unrealistic, application of the Doppler Effect is that if a car were to travel toward a red traffic light at 1/3 of the speed of light then, to the traveler, the light would appear green (green light has a shorter wavelength than red light)—probably not an excuse to proffer next time you get pulled over by the cops for jumping a stop light! Anyway, we digress; the point is that exactly the same principle is used to measure the speed of a baseball. A gun shoots a beam of radio waves that reflects off the ball. By measuring the wavelength change of the reflected beam we can calculate speed.

Understanding how radar guns work is all well and good, but the controversy surrounding them is their measurement reliability. Let’s have a look at some different sources of error, of which there are at least three.

1. Point of measurement
2. Angle of incidence
3. Gun calibration

By understanding each effect, we can start to pinpoint the size of radar measurement error and what the uncertainty is in pitch speed.

I found the analysis interesting and enlightening, although when you get down to the technical aspects, I’m lost, got no clue. 

But I encourage the Beamer’s entire article as must-read for all of you heavy heat officianados.  It’s gonna be real interesting to clock Daisuke Matsuzaka’s speed during the coming season — they say he’s a rocket as well.

The burning question this season; who will break the 105 mph barrier?  And when will we see that fictional 126 mph burner become reality?

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This entry was posted on Thursday, February 15th, 2007 at 6:34 pm and is filed under Real-Time Baseball News and Commentary, All Time Pitching Highlights. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.