WNNZ (640 AM) is a Class B regional radio station licensed to WESTFIELD, MA. Operating with 50 kW daytime power using a directional (different day/night patterns) antenna system with 3 towers. At night it operates at 1 kW. After sunset, skywave propagation can extend the signal across much of the surrounding region. The station is owned by University of Massachusetts Amherst. It broadcasts a Public radio format.