With respect to the formulas referenced in § 1.1406(d)(1) and (d)(2) , the space occupied by an attachment is presumed to be one foot. The amount of usable space is presumed to be 13.5 feet. The amount of unusable space is presumed to be 24 feet. The pole height is presumed to be 37.5 feet. These presumptions may be rebutted by either party.
47 C.F.R. §1.1410