47 CFR §73.1705

1. (a)Commercial and noncommercial educational TV and commercial FM stations will be licensed for unlimited time operation. Application may be made for voluntary share-time operation.
2. (b)Noncommercial educational FM stations will be licensed for unlimited and share time operation according to the provisions of § 73.561.
3. (c)AM stations in the 535-1705 kHz band will be licensed for unlimited time. In the 535-1605 kHz band, stations that apply for share time and specified hours operations may also be licensed. AM stations licensed to operate daytime-only and limited-time may continue to do so; however, no new such stations will be authorized, except for fulltime stations that reduce operating hours to daytime-only for interference reduction purposes.