Taking the next step in its ongoing efforts to revitalize the AM broadcast service, the Federal Communications Commission (“FCC”) has authorized AM radio stations to convert to all-digital broadcasting. Making such a switch is expected both to improve the quality of the signal received by listeners and to expand the area in which the audience can receive a listenable signal. Another advantage is that such broadcasts can include metadata, such as song and artist identification, station identification, and the like, plus there is the future possibility of a separate multicast AM channel. The primary downside is that current analog receivers will be unable to pick up the all-digital broadcasts, which means that listeners that currently do not have a digital AM receiver will need to obtain one.

The FCC repeatedly emphasized, however, that any decision to change to all-digital operation is entirely voluntary. The FCC expects that different AM stations will make different decisions, especially at first, based on the availability of digital receivers in a particular market, the make-up of a station’s audience, the format, and the investment required. Because the change to all-digital is voluntary, the FCC is not as worried about transition issues or potential loss of service to existing listeners. Likewise, the likely gradual change will make it easier for the FCC to respond to any interference issues that might unexpectedly surface.

The specific standard authorized is the HD Radio in-band, on-channel (IBOC) mode called MA3. The FCC stated that it chose the HD Radio brand now owned by XPeri Corporation because it is the only feasible technology option in the near term, but it did not rule out considering other technologies in the future should they develop.

The FCC initially authorized hybrid operation for AM stations in 2002, using the HD Radio MA1 standard. Such transmissions include both analog and digital signals, with the analog signal in the center of the frequency and the digital signal on sidebands. In the all-digital MA3, there is no modulated analog carrier signal, which means that the power level of the digital broadcasts is increased. Two configurations of the MA3 signal are possible: a 10 kHz primary carrier-only configuration (“core-only mode”) or a 20 kHz configuration using digital-only sidebands (“enhanced mode”). Such operations have been tested by the NAB Labs and a small group of AM stations over the past few years.

The results have shown a number of advantages of the all-digital operation. These include a clearer and more robust signal which is better able to overcome noise and interference than even hybrid stations can. Additionally, in what may come as a surprise to those familiar with TV’s digital “cliff” effect, weak all-digital AM signals that are at the outer range of coverage can still be received and decoded by digital receivers. Further, the all-digital AM is energy and spectrum efficient, as energy usage is comparable to analog AM stations, but the signal can be received more clearly over a wider area.

The obvious disadvantages that may discourage stations from making an immediate change to all-digital operation are the costs of making the change and the scarcity of digital receivers. Stations must remember to factor into the transition costs possible license fees due to XPeri Corporation. Another possible complication is Emergency Alert System (“EAS”) requirements. If an AM station is a primary station monitored by downstream stations, it must make sure that those downstream stations have the ability to receive any EAS alerts.

Typical requirements for broadcast stations also will continue to apply. For example, if the all-digital operation should cause interference, the station must take remediation steps. Likewise, compliance with operating power and power spectral density requirements is still required. Further, all-digital stations must broadcast at least one free, over-the-air programming stream with audio quality at least equal to analog broadcasts.

If a station does decide to make the switch, the licensee must file a digital notification on the existing FCC Form 335-AM, and must wait at least 30 days after public notice of such notification to begin the new broadcasts. Additionally, such notifications must be filed if a station increases operating power or changes from core-only to enhanced operating mode. Finally, stations must give reasonable notice to listeners of the plan to go all-digital. The FCC has not imposed the detailed and regimented notice requirements applicable to other transitions, but simply expects them to be comparable to other public notices.

Now, it remains to be seen whether digital broadcasting operations will save declining AM stations, or is it just too little, too late.