Public opposition to the siting of telecommunications masts tends to focus on perceived health risks, yet scientific evidence suggests that mobile handsets may constitute more of a risk. This paradox is usually explained in terms of cognitive or communication deficit models that contain an implicit thesis of protest actor irrationality. Recent authors (e.g. Burgess, 2002, 2004;Taverne, 2005) have, however, been more explicit in arguing that such protests are an irrational reaction to media constructed fears and state mismanagement of techno-infrastructure modernization. Together these approaches form what we call the ‘New Irrational Actor Model’. Drawing on insights from social movements theory and data from a 12-month case study of the campaign against Terrestrial Trunked Radio (TETRA) telecommunications masts in north-east Fife, we argue that contrary to the ‘New Irrational Actor Model’, the anti-mast protesters utilize multi-form modes of substantive and instrumental rational action.