An 80-year-old Edgartown man was rescued Monday morning by the Edgartown Fire Department from a ham radio tower in his yard. William Welch, an electrician and avid amateur radio operator, got his sneaker caught atop a 20-foot-tall backyard antenna after he scaled the structure to secure it ahead of the impending nor’easter, his wife Betty told The Times. Firefighters were dispatched at around 10:45 am to 7 Welch’s Way for a report of a man trapped on a tower.