Up to what size dish can a standard j-pipe support.Thinking about increasing my
dish size from 24 to 48 '' hoping to avoid problems with heavy rain this football season.
What is a standard "J" pipe? Depending on service and time period the diameters have ranged from 1 5/8" to 2 1/4" and lengths have veried with dish msnufacturers & models. A 48" dish had better come with a large diameter pipe and thick wall thickness on that pipe. I would expect a need for external braces you are increasing the wind load by more than the doubling of dish size.
I assume you currently have a 24" "round" dish aimed at 101. Are you in a marginal signal area that a 24" dish isn't big enough? In most of the US that is adequate upgrade for signal problems.