I have just went through the radar gun calibration on my Generation 3 20/20. And with the tractor setting still it will show the radar speed fluctuating from 1 to 14 mph sometimes. But as soon as I start moving it reads accurate speed. I have this gun hooked into the tractor for vehicle speed and it matches my gps speed perfect and never fluctuates on the tractor speed display. Has anyone seen this before. I have vdrive on our planter and this is all new to us this year. I am just afraid that with the planter down and sitting still when the monitor sees that radar gun speed moving around it will start turning meters when i am not moving.