Broadcast Technology

Stations Testing IBOC (In-Band
On-Channel) Broadcasting

The implementation of In-Band On-Channel (IBOC) digital radio broadcasting is moving forward in the United States despite mixed reviews. IBOC received the endorsement of the National Radio Systems Committee for fulltime use on FM, but only daytime use on AM because of nighttime skywave interference issues. Daytime tests were completed at 1500 WTOP Washington DC last March, and nighttime AM radio tests are being evaluated at 700 WLW Cincinnati and 710 WOR New York

A press release from WOR engineering provides a pretty good overview:

Buckley Broadcasting/WOR has entered into an agreement with iBiquity Digital Corporation that will once again make WOR a pioneer in the broadcast industry. WOR will be a test station for IBOC Digital AM radio. IBOC Digital will offer AM stations FM stereo audio quality.

WOR will be the first AM station in New York City to broadcast a digital signal. The average listener will not notice any difference in WOR’s (analog) signal. WOR’s participation in the testing of IBOC transmission will be instrumental to the commercial launch of the technology.
For the past 10 years, there has been a movement afoot to have AM and FM broadcasters begin a transition to a digital transmission method. Various methods have been proposed. The IBOC system for FM stations has been approved for use on FM, and it has been recommended that the FCC add rules to start implementation of FM IBOC and AM IBOC, but during daytime only for AM stations. AM stations have different issues regarding transmission than FM stations do. This is where WOR will come in.

AM signals bounce off the atmosphere at night. This is one reason WOR employs a directional transmitting antenna. There are questions as to how Digital AM will perform with skywave interference. There also are questions as to how the digital portion of an AM signal will react in the ‘concrete canyons’ of New York City (and other major cities, as well). WOR will be instrumental in helping iBiquity identify these issues.

Thomas R. Ray, III, Corporate Director of Engineering for Buckley Broadcasting/WOR states,

I take great pride in having our radio station be part of the development of one of the biggest technical advancements in radio broadcasting since FM stereo in the 1960s. WOR has been a pioneer since being one of the only radio stations on the air in the U.S. in 1922. We have been part of the development of the profanity delay, were pioneers in the development of the AM directional transmitting antenna, and were one of the major players during radio’s ‘golden era’ by forming the Mutual Radio Network. I’m proud of being given the opportunity to pilot WOR through another technical pioneering phase.

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