When I signed up for Directv in May, 1995, an 18" round dish was installed. I was getting a little too much rain fade so I had it changed out for a 24" dish. Things improved. Now thirteen years later I am thinking of upgrading to a slimline dish and HD service. Will the slimline dish pick up as much signal as the 24" round dish that I currently have? If not, is there a larger slimline dish that would do as well or better at knocking out rain fade than my 24" round dish?