The introduction of a more majoritarian electoral system is expected to result in the consolidation of a party system as predicted by institutionalists. However, voters must have information on party viability and be able to coordinate with other voters within a constituency for an electoral system reform to have the expected outcome. I argue that the introduction of independent local radio frequencies can promote party consolidation by enabling coordination on viable candidates because of better information that becomes common knowledge. The effective number of parties (ENEP) is expected to be lower in constituencies where a larger proportion of voters listen to local radio. To test this hypothesis, access to television signals is used as an instrument for radio listening behavior to address potential reverse causality. Using 2SLS, I find that an increase in one standard deviation in regular radio listening is associated with a decrease of 0.42 ENEP in Thailand.