The following lines were added (+) and removed (-):
When frequency is high enough it penetrates the E region it then may be reflected back by the F1 region, the first part of the F region of the ionosphere. When frequency is high enough it penetrates the E region it then may be reflected back by the F1 region, the first part of the F region of the ionosphere. Then with higher frequency F1 is penetrated and F2 is reflective. With each increase the next layer provides greater distance DX. The maximum skip distance for the E region is around 1550 miles and 3100 miles for the F2 region.