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NAB Radio Board Endorses NighttimeAM IBOC Operation
Washington - The NAB Radio Board placed a final piece in the IBOCpuzzle by voting to endorse interim AM IBOC nighttime operation at aJanuary 20 meeting. This endorsement is expected to weaken oppositionto full-time HD Radio AM that had previously come from AM broadcastersconcerned with the loss of AM nighttime fringe analog coverage.
The argument for endorsement came in a statement from the NAB digitalradio committee that suggested that the improved AM HDC codec wouldbring audience and revenue gains sufficient to offset any loss toanalog fringe coverage posed by interference from HD Radio AM's primarysidebands. The board stated that, "in the event that there arereductions in stations' nighttime analog service areas beyond thosepredicted by the studies, the FCC should take steps to address thoseproblems." The board also agreed to recommend that the NRSC shouldpursue "modulation and transmission IBOC standards (for FM and AMIBOC), which include provisions for advanced data applications."
The day vs. nighttime digital operation issue was believed by many tobe a significant stumbling block for AM broadcasters consideringwhether to invest in an HD AM upgrade at their facilities. It is as yetunclear how the FCC will act on the basis of the NAB'srecommendation.
Starling, Bergman & AgnewDiscuss Tomorrow Radio Test Results with Radio Magazine
In a Jan. 16 conference call with Radio magazine EditorChriss Scherer, representatives of the Tomorrow Radio project detailedtheir experiences during the recent testing of supplemental audiochannel transmission via HD Radio. The project wasconceived with an eye to exploring multi-channel broadcastingpossibilities for NPR's approximately 750 member/affiliate stationsacross the United States. The tests, conducted over HD Radio signalsoriginating from NPR affiliate stations KALW-FM, San Francisco,KKJZ-FM, Long Beach, and WETA-FM, Washington, DC, were designed toevaluate 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 ofengineering, Mike Bergman, sr. manager digital broadcast, Kenwood USA,and Dave Agnew, sr. FM applications engineer, Harris Corporation, wereupbeat regarding test outcomes, and had a number of observations toshare. One of the most gratifying discoveries, according to the group,was that acceptable performance coverage in the supplemental audiochannel (SAC) mode was considerably better than anticipated and nearlyimmune from multipath, a distinct departure from today's analog SCAs.Another pleasant surprise was the speed with which the Kenwood-suppliedreceivers were able to switch between the SAC and main programchannels. The KTC-HR100 receivers were essentially production unitswith no physical modifications - only software enhancements wererequired to provide the ability of receivers to detect, displaypresence, and select SAC operation.
Reflecting on the FCC's role in regulating the transition to HDRadio/IBOC, group members suggested that the FCC's current approach ofallowing broadcasters to adopt at their own pace is the best way toprotect both industry and public interest in the new technology. Byassuming a flexible, progressive attitude towards new technology, theysaid, the Commission will accommodate innovation and refinement bypermitting market forces to drive the broadcaster adoption process. Thetrio unanimously expressed confidence that the FCC will continue toallow advances in IBOC implementation under that same philosophy.
The test data summary, compiled by consulting engineers Hammett andEdison, is slated for presentation to the FCC within a matter of weeksfor evaluation and possible rulemaking.
Broadcasters Weigh in on Use ofSeparate Digital/Analog Antennas
In a response to a Dec. 8 Public Notice request for comments by theFCC, a substantial majority of broadcasters appear to favor thepossibility of the Commission permitting FM stations to implement IBOCtransmission using separate, co-located antennas for transmission ofdigital and analog signals. This IBOC/HD Radio configuration, known as"space combining," was suggested by a field test report submitted by anNAB sponsored ad hoc technical group on July 24, 2003.
Among those filing comments in support of a potential rulemaking wereradio groups Infinity, National Public Radio, Cox Broadcasting, GreaterMedia, Susquehanna and Summit Media. Not surprisingly, the NAB, a primemover behind the proposal, along with antenna manufacturers Dielectricand Shively Labs, also favored positive action.
The only opposition voiced was by a few individuals and groups who areopposed to the adoption of IBOC on a general basis. No specifictechnical objections were raised by the opponents.
Representing the perspective of a large radio group was InfinityBroadcasting, stating that "Infinity agrees with the NAB's view thatthe Commission should authorize broadcasters to implement the separateantenna approach, for both financial and operational reasons…areduction in the implementation cost should allow for a moreexpeditious rollout of IBOC transmissions and the attendant improvedservice that over-the-air digital radio will provide."
Likewise, small-market operator Summit Media commented that "smallcompanies with…limited growth potential in a rural area will findit difficult to justify the hefty expense of a combiner system foranalog and digital transmissions…we therefore encourage the FCCto adopt this separate antenna system for IBOC so that smallercompanies in rural areas will have a better opportunity to afford thisupgrade."
With the window for comments and replies now closed, the FCC willdeliberate the issue before taking any further action. Both commentsand replies pertaining to the issue can be viewed at www.fcc.gov/cgb/ecfs by searching the database forcomments or replies pertaining to MM Docket # 99-325.
An introduction to the new language surrounding HD Radio
: The AM HD digital modulation components that exist betweenfrequencies approx. 10kHz and 15kHz distant from the AM carrierfrequency. These sidebands partially occupy a given AM station's firstadjacent channel.
secondary sidebands: The AM HD Radio digital modulationcomponents that exist between frequencies approximately 5kHz to 10kHzdistant from the AM carrier frequency. These sidebands partially occupya given AM station's first adjacent channel.
tertiary sidebands: The AM HD Radio digital modulationcomponents that exist between frequencies approximately 5kHz distantfrom the AM carrier frequency and the carrier itself.
Digital DA and Router PermitFlexible Workarounds at HD Radio-Equipped Transmission Facilities
For broadcasters planning the installation of HD Radio FMtransmitters, the ability to respond to equipment failures on a timelybasis depends on installing hardware to provide alternate digitalsignal routing. According to a white paper, entitled HD RadioChecklist authored by Omnia Audio's Frank Foti, installing an HDRadio exciter without taking redundancy into account may invoke the oldadage that "you can't go home again." The problem, Foti explains, isthat any failure of the digital exciter may preempt both analog anddigital transmissions, owing to the fact that the current generation ofdigital exciter designs also perform the time aligning of the analogaudio stream required to assure seamless analog to digital transitionin a listener's receiver. Thus, if the digital exciter fails, there isno longer a program audio stream available for the analogexciter.
Foti goes on to suggest a flexible and cost effective work-around forthis problem. By installing an AES/EBU digital DA at the output of thestation's audio processor, combined with a digital router at the AESinput of the station's analog exciter, a parallel stream of the maindigital program signal can be routed directly into the analog exciterin the event the digital exciter fails. Because HD Radio receiversautomatically 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 routeroffer other possibilities, such as flexible monitoring and the abilityto 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 www.omniaaudio.com/tech/HDChecklist.htm.
WXGI First IBOC AM in Virginia
Richmond, VA - On Jan. 26 Richmond's WXGI-AM 950 was officiallyinaugurated its full time digital operation. In fact, WXGI actuallymade 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 andimprovements while awaiting the first shipments of HD receivers toconsumer electronic retailers.
Arrival of those receivers became a reality with the first sale of anHD Radio in Cedar Rapids, IA, on Jan. 7, coinciding with the premiereof HD Radio units by several major radio manufacturers at the ConsumerElectronics 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 megamergers and radio conglomerates, it's especially rewarding to lead thepack as radio begins industry wide conversion to digital."
Howard University Launches CommercialHD Radio FM
Washington, DC - On Jan. 21, America's leadership received anofficial invitation to participate in the digital radio revolution asWHUR-FM 96.3, owned and operated by historic Howard University,formally commenced HD Radio operations. In a press conference held atthe station's transmitter site in the DC area, Jim Watkins, generalmanager, noted that WHUR was the first commercial station in thenation's capital to use the new technology. "The digital conversion isa 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 superiorCD-quality sound, [IBOC] will also give us the capability oftransmitting important information, such as breaking news, AMBERAlerts, and customized weather and traffic. Most importantly, it willbe an invaluable training resource for the University'sstudents."
WHUR-FM features programming in an adult contemporary format and, sinceits inception on Dec. 10, 1971, has received numerous public serviceawards, including the Crystal Award from the National Association ofBroadcasters and a March of Dimes Achievement in Radio awards.
Howard University, founded in 1867, also owns WHUT, the onlyAfrican-American owned public broadcasting station in the U.S.