I think what I'll do is dig the holes 45". Then I'll ad 3" of pea
gravel to the bottom of each hole. This should give me 6 1/2' of post
above ground to fasten the cable. I'll bring my concrete up above
ground level and dome it for water run off. Then I will seal the area
all around where the post meets the concrete with silicon caulk.
Hopefully this will work out for me and the posts will give me at least
ten years of use.

Rich