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 exact wording of the rule states: For example, if the instrument of authorization states sunrise as being at 5:30am local standard time in April, the station does not require PSRA operation since sunrise time is prior to the 6:00am rule.
PSSA operation allows the station to remain on the air an additional two hours at reduced power level determined by several factors: There are no specific provisions related to daylight saving time within PSSA operation.
The first presunrise authorizations came from a proposed rulemaking in 1967 (Operation by Standard Broadcast Stations, 8 FCC 2d 698 (1967)).