I did this Mod a while ago but I used chain as the ramp support instead of cable. I decided to go with cable and corrected that today... Chain was a good Idea because you could just jump a link to keep things even but I did not like the way it looked.
Upper eye let is 3/8" stud drilled through the steel frame.
At the bottom I use a Turnbuckle for adjustment
Future plans are to get a patio room....