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Stalker Engineers (background) clock baseballs pitched through the ballistic chronograph.
Just how accurate is the new Sport 2, and how does it compare to the competition?
Most radar guns advertise "accurate to within +/- 1 to 3 mph." Stalker radar guns are accurate to within .1 (one-tenth) of a mile per hour (or km/h). And we know this because…
To find the answer, Stalker Radar conducted extensive testing to confirm the accuracy of the Sport 2 and compare it to competitors' radar guns.
How Did They Do That?
First, the tools needed to determine speed were set up:
• A line-up of mounted radar guns. This directed the aim and prevented any movement.
• Two additional guns were hand-held. These were older Stalker Pro Ka-Band radar guns.
• A ballistic chronograph (an infrared beam array within a framed box) was used to measure the ball speed and compare it with the speeds captured by the radar gun lineup. This instrument is typically used to measure the speeds of rifle bullets, so its 0.3% accuracy was more than adequate for the task of measuring baseball speeds.
• A college pitcher and catcher.
• A variable-pitch pitching machine. The first two pitching machines we tried didn't make the cut; the third allowed adjustments to simulate actual pitches.
• A PC to record the results.
• A team of Stalker engineers to run the tests.
Stalker Accuracy Testing Slide Show
Let the Testing Begin
Our accuracy testing actually consisted of two separate tests. The first test required a pitcher to accurately throw a baseball through the ballistic chronograph towards the line-up of mounted radar guns. The speeds recorded by the guns were recorded on a PC and entered into the database along with the speed recorded by the chronograph. The Doppler shift audio was also recorded.
The second test employed the pitching machine for ball speed consistency. To maintain the accuracy of the testing, groups of pitches in several speed ranges were thrown and recorded and entered into the database.
STALKER SPORT 2 BASEBALL
Maximum Speed Errors vs Speed and Signal Strength |
| Speed (MPH) |
Error (MPH)
with strong
signals |
Error (MPH)
with medium signals |
Error (MPH)
with weak
signals |
| 10 |
0.12 |
0.22 |
0.67 |
| 25 |
0.15 |
0.25 |
0.70 |
| 50 |
0.21 |
0.31 |
0.76 |
| 75 |
0.26 |
0.36 |
0.81 |
| 100 |
0.32 |
0.42 |
0.87 |
| 125 |
0.37 |
0.47 |
0.92 |
| 150 |
0.43 |
0.53 |
0.98 |
Scoring the Accuracy Test
The Doppler shift audio was also sampled. Part of the Doppler shift data included the pitcher's motion and the tracking of the ball. By filtering out the background noise, our engineers extrapolated back to the moment of the pitcher's release point of the ball and calculated the exact release speed!
This is important because as soon as the ball is released, it starts slowing down as the ball approaches the batter and catcher.
Top Marks for the Top Gun
Finally, the speed recording accuracy results revealed for the
Stalker Sport 2 :
• Less than 1% missed pitches
• Consistently accurate when compared to both the chronograph and the Ka-Band guns.
The chronograph of the 10 Sport 2s tested showed there was less than 1% missed pitches. Tested against older Stalker models, competitors, and the chronograph, the recorded results for the Sport 2 were consistently accurate.
And one last thing...
We discovered that the Stalker Sport 2, the Stalker Sport Classic, and the ballistic chronograph agreed closely on nearly all measured speeds, but a competitor's gun measured 1 to 3 mph higher on almost every pitch!
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FEATURES
• 2 - Year Warranty.
• Simple, baseball-specific operation.
• 2 Active Speed Windows - Both Peak Speed and Plate Speed.
• 3 - Hour Battery Life - Uses common AA NiMh batteries with low
charge indication.
• 10-millisecond speed acquisition time.
• Stopwatch function - Simultaneously measures pitches and times runners -
optional stopwatch cable required.
• Standard Data Port. RS-232/RS-485, 1200 baud to 38.4 Kbaud - communicates
with any serial device.
• Two transmit modes - Pull-to-transmit; pull-on, pull-off.
• Multiple units of measure - MPH and KM/H.
• Recall Previous - Recalls previous 5 readings.
• Default settings are optimized for measuring pitch speeds - User presses
the MENU key to customize the settings.
PERFORMANCE
300 feet for baseballs
DIMENSIONS
Height: 8 inches
Width: 3 inches
Length: 6 5/8 inches
Weight: 1.70 pounds
(including batteries) |
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