Publication of the FCC's Second Report and Order in the Federal Register on Aug. 16 means that the long-awaited IBOC digital radio rule changes will become the law of the land on Sept. 14.

Among the most controversial new provisions will be the green light for 24-hour HD Radio hybrid operation on AM. Critics of Ibiquity's implementation of AM IBOC digital transmission have charged that many stations currently serving a significant audience within secondary nighttime coverage areas will lose that service area to digitally generated adjacent-channel interference. In a separate but related move announced just this week, the FCC appears to be addressing AM owner coverage anxieties by tendering an NPRM that would grant new FM repeater privileges to eligible AM licensees.

Among other key provisions set to go into effect include the right for FMs to commence HD Radio multicasting without experimental authority grants and use of separate FM antennas for HD Radio hybrid operation without STAs.

Other matters, such as specific public service requirements, limitations on and regulatory fee assessments for digital subscription services, and what role multicasting will play in any new ownership equation remain to be addressed by future rulemaking.