No Radar Gun?


#1

How would you measure velocity without a radar gun? I would say inaccuracy by 3-5 mph is permitted for me. I would be interested to hear some methods you guys might have. I tried these velocity apps but found that they were off by quite a lot.:joy::joy::rofl:


#2

Find a setup on a road that’s not that well traveled, that says “YOUR SPEED.” These setups are road radar devices that tell you what you speed is. Usually, these devices are on a trailer, or even sometimes put in place with some sort of temporary platform.
Get someone to catch you by standing next to the radar speed display… toss a few … then see in live time what your velocity is.
A long time ago, I saw some youngsters doing this on a backroad. They seem to be having a lot of fun.
Now I have no idea how accurate these things are.


#3

Just remember…a few of the led’s might be iffyThe Rookie


#4

You could use a stopwatch to estimate the speed. Find the speed in feet per second and then convert to miles per hour.


#5

The challenge with what you are asking is that measuring a ball is harder than people think. A baseball slows down by about 8 MPH from the pitcher to the catcher. This means a 90 MPH pitch is only 82 MPH at the plate. So it takes a very good radar gun to even be able to pick up the speed at the release point. So even throwing into a police radar trailer like the one shown above will not be the same as a professional baseball radar because it is not designed to look for a ball slowing down. In fact it is hard to get the accuracy you are asking for of 3-5 MPH even with a $3000 Rapsodo system. Take a look at a recent report on accuracy measurements by Driveline Baseball: https://www.drivelinebaseball.com/2018/07/diamond-kinetics-pitchtracker-rapsodo-pitch-tracking-technologies/
You can see from the measurements that the speeds can be over +/- 6 MPH from a good gun.

Most of the Apps that are out there are basically a stopwatch with a calculation built in. There are 2 challenges here, first if you make a perfect timing you can still only get the average speed and not the release speed. And second, since the ball is only in the air for about 1/2 a second and the human reaction time is around 1/4 of a second and you need to precisely time the start and stop of the pitch, this has huge errors involved. There are other methods out there, but all of them have their own challenges. Making a measurement of velocity on a moving ball that is rapidly slowing down due to air resistance is a very difficult challenge. If you would like to talk about any of these trade-offs, we are always happy to help. You can call us toll-free at 888.381.2672 weekdays from 9 AM to 5 PM Pacific Time. Thanks,
Chris Stewart / President, Pocket Radar Inc.