The Board of Appeals will hold a public hearing Wednesday on a request from Sprint Spectrum to upgrade communication technology equipment at 51 Melrose St. The project includes the removal and replacement of three antennas. Other public hearings will be held on requests for home improvement projects: installation of a third-floor dormer at 15 Faxon St.; construction of a 2½-story addition to a home at 85 Richardson Road; and expansion of an existing deck and construction of two paved parking spaces at 54 Upham St. The hearings will be held at 7:45 p .m. in the aldermen’s chamber at City Hall.