In USA AM broadcasting, presunrise authorization (PSRA) and postsunset authorization (PSSA) are permission from the Federal Communications Commission to broadcast in AM on mediumwave using a power level higher than what would normally be permitted prior to sunrise/after sunset, or in the latter case, provide Class D stations with service into the evening where they would otherwise be required to sign off. Sunrise and sunset times are provided on the licensee's basic instrument of authorization.
The power level for both PSRA and PSSA service cannot exceed 500 watts. Power calculations are based on co-channel stations.