One needs a tall pole because the low corner of the array tilts and turns far below the gimbal.
The seasonal adjustment angle A and the daily rotation angle Balong with the length and width of the array determine how low the corner goes.
The Seasonal Tilt
The seasonal tilt lowers the centerline ½ the Length times the Sin of angle A below the pole top.
Seasonal Tilt = L/2 SIN A
The Daily Rotation
The maximum allowable rotation of the Tracker from center is 45º. The daily rotation turns the corner of the array lower yet by ½ the Width times the Cosine of angle A times the Sine of angle B where the angle B is the angle the Tracker has turned about the axle from noon (usually 45º).
Daily Rotation = W/2 (COS A) SIN B
A F-Series-168 Track Rack™ with a maximum rack dimension of L= 192” (North, South dimension) and W= 169” (East, West dimension) is set permanently with a seasonal tilt of 30 degrees.
How tall should the pole be if the corner can reach to within 12” of the ground?
The seasonal tilt of 30º turns the array down:
192”/2 x Sin 30 degrees
= (96) x .5
A daily rotation of 45º turns the array corner down:
169”/2 (Cos 30 Sin 45)
= 84.5 (.6124)
For the corner to always be held at least 12” above the ground, the pole would be 111-3/4” long. Seasonal Tilt + Daily Rotation + Ground Clearance
= 48” + 51-3/4” + 12”