There is a small bit of homework required to establish the turning radius of an antenna. You have to figure out the hypotenuse of a right triangle.

For this exercise we are using the following definitions for the formula:

**R** = Turning Radius

**B** = Boom length from center of the mast

**L** = Longest Element Length from Boom

The diagonal line [**R**] (hypotenuse) in a right triangle can be figured out using the following information:

**Width of the triangle** [**B**] would be the distance from the center of the mast to the end of the antenna boom. *Note: some antennas are offset* (not balanced 50/50 from the center of the mast), so the boom length on each side of the mast may be different. Choose the longest length.

**The Length of the triangle** [**L**] would be 1/2 of the longest element length (usually the rear reflector).

The formula for the hypotenuse is: [**R]** = Square Root of (**B**^{2} + **W**^{2})

For the following example:

The longest boom length from the center of the mast of the antenna is [**B**] = 15 feet.

The longest element length is 24 feet, so use half of that length which makes [**L**] = 12 feet

The hypotenuse [**R**] of the right triangle (**which is the Turning Radius**) would be: 19.209 feet.

(Be safe and round it up to 19.5 feet).