Originally Posted by tennis_ocd
Unless your gunning guys on tour or extremely accomplished Div 1 type guys with live arms, 97 mph is lightning fast. Assuming the serve is somewhat accurate and repeatable, it's an excellent serve; congrats! 120 mph is simply another dimension.
And fwiw, of course the position of the gun matters; it's measuring bounced back waves and the closer in line with moving object, the more accurate. (Small incident angles are fine but they won't measure from the side.)
I have a pocket radar; it's amusing to play around with. I find the very experienced (teaching pros/ex-div 1 types) are impressed with its accuracy and size; the young kids and rec players always shake their heads and comment that it has to be reading too low. lol.
The owner of that gun is the former #1 singles player in the state. He's also a USPTA-1 coach and he bought that unit at the conference this past month.
He was only able to serve 91. After two other guys and myself topped it out at 97 we all started to suspect something was up. After Googling around we found someone else who was using it for tennis and seemed to be getting slower than usual results.
Apparently being 25 deg. off can produce results 10% slower. Also, being above the level of contact and being directly inline with the balls path of travel affects accuracy of the result.
The gun is accurate to 1 mph, but only assuming you're using it right, at the right vantage point.
(and for those conspiracy theorists, he's not the teacher in my video. The teacher in my video is a USPTA-1 coach and played college tennis for two teams, but AFAIK, he didnt continue after college)