This paper traces strategies used by the Radio Preservation Task Force of the Library of Congress's National Recording Preservation Board to develop a publicly searchable database documenting extant radio materials held by collecting institutions throughout the country. Having aggregated metadata on 2,500 unique collections to date, the project has encountered a series of logistical challenges that are not only technical in nature but also institutional and social, raising critical issues involving organizational structure, political representation, and the ethics of data access. As the project continues to expand and evolve, lessons from its early development offer valuable reminders of the human judgment, hidden labor, and interpersonal relations required for successful big data work.