There may be an endowment fund that this type of expense might already qualify under, they can help you identify if any such monies exist.
If not, try reaching out to alumni, but DO NOT DO THIS ON YOUR OWN. Work with your school's Alumni Relations group. Alumni Relations likely won't agree to start cold-calling random alumni for your pet project. So propose that Alumni Relations cross-references their alumni list with the Ham Radio callbook. Should be an easy database join (match by name and address). You'll get highly qualified hits that should result in excellent yields. And you can have meaningful conversations with Alumni that should help build/rebuild the alumni's connection with the school, even if they don't give.