Thursday, March 22, 2007

Nighttime AM IBOC approved - final IBOC rules adopted

The Radio Ink online news site reports the FCC has this morning approved final rules for digital terrestrial radio in the US.

Read the link for more details. A few highlights:


  • No prior FCC approval is necessary to begin digital operation.

  • AM stations, previously limited to daytime-only digital operation, will be allowed to run their digital signals at night.

  • Stations must offer at least one free-to-air program stream, simulcasting their analog signal. Additional program streams may be broadcast, either free or subscription. (FM only; AM IBOC lacks the technical ability to multicast)

  • Content rules - EAS, legal IDs, etc. - will be applied to all streams of the IBOC signal.

  • Digital-only stations will not be allowed at this time. (apparently this will stymie the plans of North Carolina stations WHDX and WHDZ which had reportedly planned to sign on as digital-only operations) IBOC stations must maintain their analog operations.

  • No deadline has been set for shutting down analog radio and going digital-only.


  • The FCC has not yet released a Public Notice on this. (keep an eye on the FCC website.) Usually, this kind of proceeding takes effect 30 days after publication in the Federal Register; said publication will take between a few days and a week. So one might expect AM stations to begin operating in digital mode at night in about 5 weeks, around the beginning of May. I would not rule out the possibility of stations that are already operating IBOC during the day receiving Special Temporary Authority to engage in nighttime digital operation before the new rules go into effect. Indeed, I would not rule out blanket Special Temporary Authority to cover all IBOC stations.

    Many of the 50kw clear-channel stations are already equipped for IBOC and will likely begin operating at night as soon as the rules go into effect. The likely result will be massive interference in the 640-1220 and 1500-1580KHz bands. I don't see the new rules spurring many stations to add IBOC though, if they aren't already running it. IBOC is not particularly popular among the smaller stations in 540-630, 1230-1490, or above 1580KHz and I don't think it will become so particularly quickly.

    I guess time will tell.

    edit:
    More links:
    FCC News Release


    Commissioner statements:
    Kevin Martin
    Michael Copps
    Jonathan Adelstein
    Deborah Taylor Tate
    Robert McDowell


    Radio World article
    another Radio World article

    2 comments:

    Anonymous said...

    The night time AM DXing will really be a mess. To bad!
    I used to enjoy that hobby.

    Since digital is "in band and on channel", why would a shut down of the analog be proposed and,
    eventually, required?

    Doug Smith said...

    I'm not at all convinced we'll see a lot more AM IBOC than we're already seeing. It was already pretty easy, from a regulatory standpoint, to adopt IBOC; I don't think the rules changes will spur many stations that weren't already IBOC to add it.

    Of course, the stations that are already authorized could make a pretty big mess out of 640-1220KHz. There are relatively few IBOC stations in 540-630 and 1230-1490 so I think these bands will continue to be relatively DXable.

    And it is very possible AM IBOC will fail in the marketplace, making it a non-issue as far as DXing is concerned. (some engineers fear IBOC could kill the AM service in the U.S. altogether! - ironically making DXing of foreign stations *easier*...)

    For an individual station, shutting down the analog would allow a greater data payload and a power increase for the digital signal. Audio quality could be improved, reception reliability improved, it might even be possible to "multicast" more programs.

    For the radio service in general, the digital signal could, in fact, become "on-channel" - if the analog was gone, the digital could be fit into the space previously occupied by the analog. The interference issues raised by IBOC would go away. (such a move would however be inconsistent with increasing the data payload)

    I think mostly, in light of the transition process for TV, radio stations simply expected the FCC to establish a policy.