The issue of interference involving digital radio broadcasting on the AM band using the IBOC protocol has made it into the corporate media. The Wall Street Journal ran a piece earlier this month on the problem. However, smoothes it over as an “unexpected consequence,” which is false: the interference is due in part to the very design of the HD Radio system. Digital-related interference also affects FM transmissions, though not nearly as severely.
The article does note that Leonard Kahn, inventor of the CAM-D AM digital broadcasting protocol, has filed suit against iBiquity on antitrust grounds. As iBiquity’s backers are essentially the major broadcasters and consumer electronics manufacturers, Kahn accuses the “cartel” of imposing a proprietary digital radio standard on the country before the FCC’s had a chance to evaluate competitor technologies like his.
The problem is Kahn hasn’t yet released any substantive technical information about the CAM-D system – just a recording of a station purported to be testing CAM-D, which gives the FCC nothing to evaluate.
Meanwhile, 721 of the nation’s 13,000+ radio stations are now broadcasting hybrid analog/digital signals, and of those less than 200 have taken advantage of IBOC’s multicast capability to add new content. National Public Radio runs webcasters as “filler” on many of its multicast channels. iBiquity blames Detroit for the slow rollout: you can get satellite radio receivers in new vehicles but there’s been no real commitment to add HD-compatible gear to the dash.
I found an interesting webcast the other day: a 16-hour online version of the NAB’s “HD Radio Workshop,” as conducted over the course of its radio convention in 2004. The range of material covered looks impressive. It’s a shame the NAB wants $50 to watch it.
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