Second career as an avionics technician
This answer assumes you live in the United States. You should consider attending a Part 147 program at an Aviation Maintenance Technician School approved by the FAA. Some avionics technicians also get themselves an Airframe mechanic's rating from the FAA because a good percentage of what a line avionics technician does has to do with components of the airframe. (As a side note, military experience as a line avionics tech is considered sufficient to qualify to take the tests for the Airframe mechanic rating). You can also become certified through a repair station, but that may only qualify you to perform specific work. You should definitely also get the FCC radio-telephone operator certification or Aircraft Electronics Technician (AET) certification from the National Center for Aerospace and Transportation Technologies.