IBOC Update - Jan 28, 2004

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NAB Radio Board Endorses Nighttime AM IBOC Operation

Washington - The NAB Radio Board placed a final piece in the IBOC puzzle by voting to endorse interim AM IBOC nighttime operation at a January 20 meeting. This endorsement is expected to weaken opposition to full-time HD Radio AM that had previously come from AM broadcasters concerned with the loss of AM nighttime fringe analog coverage.

The argument for endorsement came in a statement from the NAB digital radio committee that suggested that the improved AM HDC codec would bring audience and revenue gains sufficient to offset any loss to analog fringe coverage posed by interference from HD Radio AM's primary sidebands. The board stated that, "in the event that there are reductions in stations' nighttime analog service areas beyond those predicted by the studies, the FCC should take steps to address those problems." The board also agreed to recommend that the NRSC should pursue "modulation and transmission IBOC standards (for FM and AM IBOC), which include provisions for advanced data applications."

The day vs. nighttime digital operation issue was believed by many to be a significant stumbling block for AM broadcasters considering whether to invest in an HD AM upgrade at their facilities. It is as yet unclear how the FCC will act on the basis of the NAB's recommendation.

Starling, Bergman & Agnew Discuss Tomorrow Radio Test Results with Radio Magazine

In a Jan. 16 conference call with Radio magazine Editor Chriss Scherer, representatives of the Tomorrow Radio project detailed their experiences during the recent testing of supplemental audio channel transmission via HD Radio. The project was conceived with an eye to exploring multi-channel broadcasting possibilities for NPR's approximately 750 member/affiliate stations across the United States. The tests, conducted over HD Radio signals originating from NPR affiliate stations KALW-FM, San Francisco, KKJZ-FM, Long Beach, and WETA-FM, Washington, DC, were designed to evaluate the viability of transmitting supplemental audio channels (SAC) along with a main audio program channel.

Tomorrow Radio's tech trio, consisting of Mike Starling, NPR's VP of engineering, Mike Bergman, sr. manager digital broadcast, Kenwood USA, and Dave Agnew, sr. FM applications engineer, Harris Corporation, were upbeat regarding test outcomes, and had a number of observations to share. One of the most gratifying discoveries, according to the group, was that acceptable performance coverage in the supplemental audio channel (SAC) mode was considerably better than anticipated and nearly immune from multipath, a distinct departure from today's analog SCAs. Another pleasant surprise was the speed with which the Kenwood-supplied receivers were able to switch between the SAC and main program channels. The KTC-HR100 receivers were essentially production units with no physical modifications - only software enhancements were required to provide the ability of receivers to detect, display presence, and select SAC operation.

Reflecting on the FCC's role in regulating the transition to HD Radio/IBOC, group members suggested that the FCC's current approach of allowing broadcasters to adopt at their own pace is the best way to protect both industry and public interest in the new technology. By assuming a flexible, progressive attitude towards new technology, they said, the Commission will accommodate innovation and refinement by permitting market forces to drive the broadcaster adoption process. The trio unanimously expressed confidence that the FCC will continue to allow advances in IBOC implementation under that same philosophy.

The test data summary, compiled by consulting engineers Hammett and Edison, is slated for presentation to the FCC within a matter of weeks for evaluation and possible rulemaking.

FCC Update

Broadcasters Weigh in on Use of Separate Digital/Analog Antennas

In a response to a Dec. 8 Public Notice request for comments by the FCC, a substantial majority of broadcasters appear to favor the possibility of the Commission permitting FM stations to implement IBOC transmission using separate, co-located antennas for transmission of digital and analog signals. This IBOC/HD Radio configuration, known as "space combining," was suggested by a field test report submitted by an NAB sponsored ad hoc technical group on July 24, 2003.

Among those filing comments in support of a potential rulemaking were radio groups Infinity, National Public Radio, Cox Broadcasting, Greater Media, Susquehanna and Summit Media. Not surprisingly, the NAB, a prime mover behind the proposal, along with antenna manufacturers Dielectric and Shively Labs, also favored positive action.

The only opposition voiced was by a few individuals and groups who are opposed to the adoption of IBOC on a general basis. No specific technical objections were raised by the opponents.

Representing the perspective of a large radio group was Infinity Broadcasting, stating that "Infinity agrees with the NAB's view that the Commission should authorize broadcasters to implement the separate antenna approach, for both financial and operational reasons…a reduction in the implementation cost should allow for a more expeditious rollout of IBOC transmissions and the attendant improved service that over-the-air digital radio will provide."

Likewise, small-market operator Summit Media commented that "small companies with…limited growth potential in a rural area will find it difficult to justify the hefty expense of a combiner system for analog and digital transmissions…we therefore encourage the FCC to adopt this separate antenna system for IBOC so that smaller companies in rural areas will have a better opportunity to afford this upgrade."

With the window for comments and replies now closed, the FCC will deliberate the issue before taking any further action. Both comments and replies pertaining to the issue can be viewed at
www.fcc.gov/cgb/ecfs by searching the database for comments or replies pertaining to MM Docket # 99-325.

HD Radio Terminology

An introduction to the new language surrounding HD Radio

primary sidebands

: The AM HD digital modulation components that exist between frequencies approx. 10kHz and 15kHz distant from the AM carrier frequency. These sidebands partially occupy a given AM station's first adjacent channel.

secondary sidebands: The AM HD Radio digital modulation components that exist between frequencies approximately 5kHz to 10kHz distant from the AM carrier frequency. These sidebands partially occupy a given AM station's first adjacent channel.

tertiary sidebands: The AM HD Radio digital modulation components that exist between frequencies approximately 5kHz distant from the AM carrier frequency and the carrier itself.

Technology and Applications

Digital DA and Router Permit Flexible Workarounds at HD Radio-Equipped Transmission Facilities

For broadcasters planning the installation of HD Radio FM transmitters, the ability to respond to equipment failures on a timely basis depends on installing hardware to provide alternate digital signal routing. According to a white paper, entitled HD Radio Checklist authored by Omnia Audio's Frank Foti, installing an HD Radio exciter without taking redundancy into account may invoke the old adage that "you can't go home again." The problem, Foti explains, is that any failure of the digital exciter may preempt both analog and digital transmissions, owing to the fact that the current generation of digital exciter designs also perform the time aligning of the analog audio stream required to assure seamless analog to digital transition in a listener's receiver. Thus, if the digital exciter fails, there is no longer a program audio stream available for the analog exciter.

Foti goes on to suggest a flexible and cost effective work-around for this problem. By installing an AES/EBU digital DA at the output of the station's audio processor, combined with a digital router at the AES input of the station's analog exciter, a parallel stream of the main digital program signal can be routed directly into the analog exciter in the event the digital exciter fails. Because HD Radio receivers automatically default to analog in the absence of a digital signal, this is an arrangement that can be a ratings and revenue saver.

Beyond their utility in emergencies, the AES digital DA and router offer other possibilities, such as flexible monitoring and the ability to feed an auxiliary air chain. In every instance, the author suggests, thoughtful planning is the key.

Foti's white paper can be viewed in its entirety at

Eye on IBOC

WXGI First IBOC AM in Virginia

Richmond, VA - On Jan. 26 Richmond's WXGI-AM 950 was officially inaugurated its full time digital operation. In fact, WXGI actually made its first digital broadcast in the fall of 2003, but at that time, there were no HD Radio receivers available to the public. Since then, the station has been busy making final technical preparations and improvements while awaiting the first shipments of HD receivers to consumer electronic retailers.

Arrival of those receivers became a reality with the first sale of an HD Radio in Cedar Rapids, IA, on Jan. 7, coinciding with the premiere of HD Radio units by several major radio manufacturers at the Consumer Electronics Show in Las Vegas, Nevada.

"It's an exciting time in the broadcast industry," said Howard Keller, WXGI's director of operations and marketing. "In this period of mega mergers and radio conglomerates, it's especially rewarding to lead the pack as radio begins industry wide conversion to digital."

Howard University Launches Commercial HD Radio FM

Washington, DC - On Jan. 21, America's leadership received an official invitation to participate in the digital radio revolution as WHUR-FM 96.3, owned and operated by historic Howard University, formally commenced HD Radio operations. In a press conference held at the station's transmitter site in the DC area, Jim Watkins, general manager, noted that WHUR was the first commercial station in the nation's capital to use the new technology. "The digital conversion is a very exciting move for us" said Watkins in an earlier press release, "with HD Radio we will not only be able to offer our listeners superior CD-quality sound, [IBOC] will also give us the capability of transmitting important information, such as breaking news, AMBER Alerts, and customized weather and traffic. Most importantly, it will be an invaluable training resource for the University's students."

WHUR-FM features programming in an adult contemporary format and, since its inception on Dec. 10, 1971, has received numerous public service awards, including the Crystal Award from the National Association of Broadcasters and a March of Dimes Achievement in Radio awards.

Howard University, founded in 1867, also owns WHUT, the only African-American owned public broadcasting station in the U.S.

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