Does it matter where a radar gun is positioned? Noticed at one showcase that the gun was mounted in the press box about 18ft above the field, behind home plate. I was just curious, since I've always thought that the most accurate results were from behind the catcher/pitcher at around ground level. What, if any, affect would it have on the readings?

Yes, it is called a cosine error. Act Vel = measured Vel x Cosine (angle)

http://www.copradar.com/preview/chapt4/ch4d1.html

Scout was probably just looking at the relative differences.

Thanks for the reply.....

This gun in particular was being used by the showcase staff. It was the only gun they were using to record the pitchers velocity.

How far behind the plate was it? First of all people tend to overestimate height so there's a chance it wasn't quite that high. Second of all if it was in the press box then it was probably quite a ways back from the plate. For example if they were sitting in a second story press box then the gun was probably about 14' above the ground. A typical pitcher releases the ball about 5 or 6' above the ground. Let's say the press box was 45' behind the plate which is pretty close. That means that the height above release was, to be generous about 10'. The horizontal distance to release was about 54' + 45' = 99'. The cosine error for an 85 mph fastball would be less than a half a mile per hour.

CADad, I think he was refering to the towers at the Arizona Fall Classic (Peoria) that are about three stories high. (four fields back up to this observation tower) Not your typical set up at a field. My guess is they could be off by a 2-3MPH but everything would be relative.

BOF,
Let's say it is those towers. How far are they from the plate? Looking at google I'd say at least 150' from the mounds to the tower. Let's use 24' above the ground and therefore 18' above the pitcher and 150' from the release point. That would give us an angle of about 6.8 degrees and a cosine error of about 0.6 mph on an 85 mph fastball.

Holy C r ap batman....where do you find time for this? Do you work for a living? Gota go my boss just came in.......BTW you are probably right.

We did an event at the U of Cincinnati a couple years ago. Beautiful ballpark, but the stands were high and steep... not conducive to getting exact gun readings. We stationed a gun at field level (they actually have a glassed in area at field level behind home plate) and there was a fairly consistent 1 mph difference. Lower reading was from the seats behind home plate. This caused some people in the stands to think we added a mph to most of the gun readings, when we were actually taking the readings from a much lower and more accurate position. ½ mph can cause a 1 mph difference on the radar gun. Every once in awhile, you end up at a place where getting accurate gun readings is next to impossible.

Makes sense.

CADad, Jerry can mess around here all day long because he is the ....

The area from homeplate to the backstop was very short at this showcase....not the typical distance seen in college or many h.s. fields, and the pressbox was right next to the backstop fence. Realize that it's all relative and some fields have difficult setups. But I was just curious if the readings might vary dependent on gun location.

Yes it can. In your case I'd guess about 0.5 to 1 mph.

Applebee's Park in Lexington,Ky host the state tournament and they have the stadium radar. The gun is mounted up high around the pressbox and would read 2-3 MPH slower than the guns that some of the scouts had right behind home plate..

CADad, you are the bomb! I love all that engineer talk.