CKOI FM

La Puissance Musicale

According to Wikipedia, CKOI is still "one of North America's highest-powered FM stations". Its signal can be heard within a driving radius over almost 2 hours. CKOI broadcast over Montreal on frequency 96.9 MHz (FM), using a powerful 148,000 watts. And prior to 2019, the station's antenna used a whooping 307kW (since its installation in 1962).

For reference, the maximum strength for FM broadcasting in the U.S. is usually 50,000 in densely populated areas (or 100,000 watts otherwise). CKOI is evidently grandfathered into similar limits in Canada (its predecessor station started airing shortly after the war). Before CKOI's recent conversion, only WBCT in Grand Rapids (Michigan) operated at a higher strength (of 320kW).