KDIA (1640 kHz) is a commercial AM radio station licensed to Vallejo, California, and serving the San Francisco Bay Area. It is owned by the Salem Media Group and broadcasts a Christian talk and teaching radio format. Salem also owns KFAX 1100 AM which airs a separate schedule of Christian programming. The radio studios and offices are on Liberty Street in Fremont. KDIA transmits 10,000 watts. By day, it is non-directional, using one of the KKSF 910 AM towers in Richmond on San Francisco Bay. At night, it is directional, using a four-tower array on Noble Road in Vallejo.