Ok, I get that "RF hash" is some sort of slang for "RF interference" (think CB), but does it refer to a particular type or source of interference? Do tell.
When I think of "RF Hash" I think of a constant "sparky" sort of interference, like an insulator arcing, or RF noise from an electric motor or some gas discharge lamps or lamp dimmers. Compared to, say, lightning (non-repetitive) or white noise (not "sparky".) Whether that's the CBers definition or not, I don't know.