I hope that this email finds you well, thank you for reaching out to Rain or Shine Golf. SkyTrak measures the first few inches of ball flight so there isn’t really a minimum distance the ball has to travel, you just need a space large enough to swing your clubs and enough space for your golf mat and net/screen you are hitting into. If you are using outdoors you will want to be in a covered area as direct sunlight can affect the results of your SkyTrak launch monitor.