AM Radio And IBOC

One of the reasons, IBOC was chosen as the optimal digital technology for the US, has to do with the ability to keep stations at the current locations on the FM and AM dial. IBOC will allow broadcasters to keep their current station settings by essentially sandwiching the digital signal within the analog signal. The analog signal, which you hear now on your radio, will act like a host or carrier for the digital signal. Ideally, this signal sandwich will allow for a gradual transition from the current analog signal to a full digital transmission sometime in the future.

In other words, since the digital signal will rely on the analog signal to carry it along, you'll still be able to use your analog radio until your favorite station (or most of the stations you listen to) opt for a fully digital broadcast. How long that will take will depend on several factors, ranging from the ability of FM IBOC to actually give people CD quality sound, and the ability of AM IBOC to provide FM quality reception while still covering the wide range of long-distance AM radio listeners.

Last month, the FCC received comments on FM IBOC (at the end of the article I'll tell you how to find those comments - it wasn't easy). The majority of these comments seemed to confirm that FM IBOC meets its main purpose of providing CD quality, digital sound on the FM band. Still, many questions remained, and I think that if more people were aware of the implications of IBOC, more of those questions will be asked. In the months ahead, the NRSC (National Radio Systems Committee) will submit its report on Ibiquity's AM IBOC to the FCC for evaluation. After that, the FCC will welcome comments from the public and from radio manufacturers on the proposed use of AM IBOC technology. As you might have guessed, C. Crane is following this development very closely. After having talked with millions of AM Radio listeners for the last 25 years, C. Crane is in a rare position to offer insight on how people listen to radio and what sort of requirements would need to be met for AM IBOC to be successful.

We'll follow the developments in AM IBOC, and let you know how AM digital radio might affect your listening habits in the years ahead. As of this writing, Ibiquity's FM IBOC will go into commercial testing in New York, Los Angeles, Chicago, San Francisco, Miami and Seattle. As for AM testing, there arent many public details available at the moment, though it seems that it may initially be limited to daytime hours in order not to interfere with nighttime long-distance AM radio listening.

If you'd like to read the comments that the FCC received on FM IBOC, you should go through the following steps:

  1. Go to
  2. Click on Search for Filings
  3. Enter 99-325 under Proceeding, and hit Enter (or click on Proceeding).
  4. A big list of comments will appear - just click on the comments you'd like to read. Keep in mind that some of them are very large, and take a long, long time to load. Good luck - it is a bit tricky to maneuver that site.

If you would like to find more information about IBOC, you could also visit the following Web sites:

There's a lot to learn about both AM and FM IBOC, and the more we know, the more we'll all be able to respond effectively to this emerging technology. And don't forget to check out their question of the month to learn cool facts that will impress your friends and family.

As always, please contact us with any comments or article suggestions you might have.