Every morning, radio operators in rural communities in northeastern Congo check in with one another for word about the activities of the rebel Lord's Resistance Army. Run by NGOS, this network of high frequency radios keeps the entire region informed about threats of violence and facilitates civilian, humanitarian, and military responses. Drawing on themes of protection and security, this research project investigates the infrastructures and technologies—material ones such as the radio and roads as well as social relations of reciprocity and responsibility—that make the early warning network possible. Grounded in ethnographic observations and archival research, my research traces the history, politics, and ethics of radio as a technology of protection in the Congolese hinterland. I follow the radio network from NGO offices to rural communities, explore the colonial and missionary histories of high frequency radio in the region, and identify the social relations that are required and produced by the early warning network. In studying the actors and materials that maintain this humanitarian infrastructure, I also reveal competing understandings of security and insecurity, complex networks of obligation, and emerging political responses to instability. My research brings together the scholarship on humanitarianism, ethics, technology, and infrastructure by focusing on how older forms of communication are reconfigured as technologies of protection and emphasizing how infrastructures enable and preclude certain forms of humanitarian action, politics, and ethics.