Among processes towards democratisation, it has been asserted that alternative radio has a central role in the citizen making of the poor. However, it is important to analyse in detail what possibilities an alternative or citizens' radio has to strengthen ideas of citizenship and transform the public space into a critical and deliberative public in urban sites. I focus on one local Catholic radio station in Huaycan, a shantytown in the outskirts of Lima, Peru. I describe the radios' journalistic work, showing examples of how they mobilise local leaders and monitor democratic processes, such as municipal elections and the district's participatory budget. In addition, I show how the public uses the radio to channel their claims. I also identify the factors that prevent the radio from fully empowering the public and transforming public space into a more critical and democratic one.