This is the IBOC Section of
The Broadcast Archive

Maintained by:
Barry Mishkind - The Eclectic Engineer
last updated 12/26/08

2002 appears to be the year IBOC (In Band On Channel) Digital radio made its first "mark."

KROQ-FM (Los Angles) became the first station to "Officially" run IBOC 24/7 on September 29, 2002. KROQ chose the Orban Optimod 8400 with digital options to drive the processing. (Some stations, including one in Seattle had been running more or less consistent IBOC since mid/late 2002, but essentially in an "experimental" mode. Updated information will appear if available.)

The tests conducted in Seattle, along with other cities gave Ibiquity the strength to head toward a nationwide rollout in early 2003. What is IBOC (or IBAC - In Band, Adjacent Channel)?  Let's take a look.

IBOC for AM and for FM.

IBOC impresses digital information on top of the regular analog signal. In general, you could say it "increases the sidebands" of the station, hence some complaints from the DX crowd about making the band "hash."

Among the "pluses" claimed for IBOC:

    1. Reduced multipath on FM
    2. The ability to run more than one program at a time.
    3. The ability to send digital text at the same time.

Phil Alexander writes: "... the history of IBOC is a very ugly chapter that begins in the 1960's with FM stereo. In hindsight, that was the time to move from VHF FM analog to UHF digital, but with the existing FM service mired in a battle for survival, it was a full generation too early even though the techniques and hardware were not unknown in some circles.

Twenty years later, FM had won dominance over AM because the FCC did not act in the '70's to move the medium forward into the stereo era. The FCC induced AM stereo debacle is too well known to waste bandwidth recounting here, so I'll skip that part.

However, the FCC/industry AM stereo failure combined with years of FCC non-enforcement of electronic noise radiation rules have left AM at the low point of its history in many ways. The IBOC conversion was the FCC's effort toward AM band salvation after the broadcast industry turned down the idea of moving to UHF (the same frequencies later allocated for Sirius/XM) possibly using a scheme like Eureka, or Eureka itself. The reason for rejection was this move would have upset the coverage applecart by equalizing the audience coverage of all stations in a transmitter group.

Needless to say, the idea was a nonstarter with the dominant 50 kW owners, so the IBOC rulemaking began with a specific requirement for In Band On Channel proposals that would be evaluated. The intent was a hybrid transition period during which both digital and analog signals would be transmitted together to build receiving sets in the market after which stations could elect to discontinue analog and increase digital power levels. And, by the way, make sure the same system will work for FM (i,e., VHF) so all stations will have technical parity.

One of the entrants was the old, original AT&T Laboratories. Alas, AT&T was split and the part involved in IBOC became a Lucent asset. Lucent DR Operations and a company called USA Digital Radio were the two finalists remaining in the FCC contest when Lucent determined DR Ops did not fit within their future business plan and placed it on the block.

USADR won the FCC battle by buying their only remaining competitor and withdrawing the Lucent entry. At that point they named themselves Ibiquity. Some wags have opined it was more a play on inequity than ubiquity, but whichever it was, the rest, as they say, was history.

The reality is the Ibiquity/USADR system is not well regarded in a large segment of the broadcast engineering community, especially the "AM" part. Because they have not been open with the engineering community and have generally pursued a non-disclosure/trade secrets strategy, Ibiquity, itself, has not won many friends either. The general consensus seem to be one of false promises and under performance, both in engineering and marketing. However, they seem to have excellent lobbyists and have forged relationships with the NAB, their licensed equipment manufacturers and early adopting groups including Clear Channel.

You may wonder how they have managed to maintain a closed strategy with the FCC, however IBOC is optional, not mandatory. In a mandatory situation it appears full disclosure would be inevitable. My own view, which I have publically stated for several years, is that IBOC is a terrible system, but it has been approved by the FCC, thus it is the only one we will get. However, it may be interesting to see if DRM which I believe is superior can gain a significant foothold in the western hemisphere.