Grabbed a $30 100W adhesive-backed pan heater from the local AutoZone.
Slipped it under the dish mounting bracket (it's small, about 2" x 4") & stuck it to the backside of the dish.
Just tested it, cleared the ice & snow off the dish in under 2 minutes.
Can't imagine 100W could hurt the dish, even if left on for hours.
Sure beats reaching up to it with a broom or whatever...