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The white spaces are the frequency bands between analog television channels in the VHF and UHF range (up to 806mHZ), where over-the-air channels 2-13 (VHF) and 14-69 (UHF) have operated for over half a century. Two huge forces vied for them: a consortium led by Google and Microsoft that wanted to exploit the new space for CE wireless devices, and a collection of interests, spearheaded by national television and radio networks that had been the longtime primary legitimate users of the space, but also by theaters, houses of worship, corporate productions, and other entities that have come to rely on wireless microphones but which operated in a kind of gray area in the FCC regulations. Of particular interest was the 700mHz range, where most professional wireless operates thanks to its optimal frequency propagation, low power-versus-distance characteristics and ability to let RF travel around or through almost all obstacles. The FCC, caught between interests, commissioned a lengthy series of tests to find ways to allow new and existing applications use the space without bumping into each other. Various systems, including a leading contender from Microsoft, that asserted to be able to keep any new white-space consumer devices from interfering with existing wireless users and the new digital TV spectra, underwent months of testing, including a closely watched one that used an NFL game in September as a test bed. (The NFL, also a broadcaster, is one of the parties that opposed to opening the white spaces to consumer applications.) Despite generally negative reviews of the outcomes of the tests, on Nov. 4 FCC chairman Kevin Martin ruled that the white spaces would be open to new media. CE technology companies cheered. Martin’s own words reflected their sentiments: "Opening the white spaces will allow for the creation of a WiFi on steroids. It has the potential to improve wireless broadband connectivity and inspire an ever-widening array of new Internet-based products and services for consumers… in TV white spaces." Wireless users were disappointed and noted the potential economic impact: for instance, Broadway, where shows routinely run as many as 48 channels of wireless microphone a night, took in $939 million during the 2006-2007 season. RF interference from a new generation of wireless devices in the middle of a show could be devastating. And at a time when prerecorded music sales continue to decline, live performances are becoming the bread and butter of the evolving music industry. Of particular concern was the fact that one of the key elements of the order stipulated that wireless users would have to vacate the 700mHz part of the spectrum, where most of the music and theatrical wireless systems operate. But Wait, There’s More
The good news, however, is that there are—on paper, at least—significant allowances and protections as part of the FCC order opening the white spaces. For instance, all new devices will be required to incorporate spectrum sensing—the ability to scan the airwaves to detect and avoid signals in operation. Furthermore, the FCC determined that spectrum sensing alone would not keep devices from interfering with the signal—at least for now. To augment that, the FCC order also stipulates the establishment of an RF database to document what channels are in use in specific areas around the country (though who will compile, maintain, and manage it is still undetermined). All white space devices will need to be able to geolocate (through GPS, for example) and access this database over the Internet. Venues where wireless microphones are in use can be registered in the database, limiting white space devices in those areas (and offering a kind of amnesty for non-broadcast users), making the devices network-dependent: They cannot connect with other devices in the area until they access the Internet and geolocation system. Finally, white-space devices cannot use channels directly adjacent to ones that are being used by a fixed broadcaster, and mobile devices must avoid channels 14 through 20 altogether. Major metropolitan areas have yet another layer of wireless protection. In 13 key media cities, including New York and Los Angeles, where public safety radios utilize channels 14 to 20 (470 to 512mHz), the FCC will block CE devices from an additional two channels between 21 and 51 (512 to 806mHz) in the UHF spectrum. And the FCC doesn't want white space devices operating on VHF channels 3 or 4, in case they might interfere with DVD players and video game consoles that connect to the TV on those channels. Now What?
In the last three decades, wireless has mushroomed into a significant part of the professional audio revenue stream. With most systems operating in the 700-MHz range using frequency modulation (FM), virtually every manufacturer’s products are affected. The strategy at Shure, which as the wireless sector market leader had taken the point position early in the controversy, involves adding more frequency selections to their existing wireless product lines, and the company will enhance their existing frequency-finding software to show more precisely which the best open channels available are for a given time, place and anticipated local white-space device usage. Lectrosonics, another large wireless player, offers a plan by which users of its 700mHz products can have them reset, for a fee, to a usable frequency block in a lower range. Joe Ciaudelli, a consultant at Sennheiser, says the protections built into the FCC rulings could allow professional wireless users to stay in the UHF range successfully with a few tweaks, such as retuning for frequencies below 698mHz and employing tactics such as sharp filtering of antenna systems, distance and power management techniques, zone isolation with enhanced shielding, and time multiplexing (scheduling different frequencies for different times). But, Ciaudelli cautions, that’s still a big if. "If reality matches what the FCC order calls for, great, but there are still a lot of loose ends hanging, such as exactly when we have to vacate the 700mHz range," he says. But he believes that the decision is also an opportunity for the FCC to modernize its regulations. "Churches, casinos, corporations, and theaters all need wireless routinely now. The regulations are decades old and have been outpaced by technology." At Audio-Technica, the strategy is to leave the mHz range behind almost all together. The company began working on its SpectraPulse system six years earlier, in anticipation of a less-predictable white space environment, according to Jackie Green, A-T’s VP of R&D. SpectraPulse is a purely digital system that does not use a carrier like FM or SpreadSpectrum, but rather operates in the 6.35gHz range, far above conventional RF frequencies and actually closer to that of microwaves. Green acknowledges that this stratospheric frequency range is not as straightforward or stable an RF environment as the 700mHz or even the increasingly common 2.4gHz range has been. "That’s why it took six years," she says. "But once you get it right, it’s rock-solid and completely unaffected by white-space issues." Enough so that it was used on the third and final presidential debate broadcast in October. But SpectraPulse's cost—twice that of other high-end professional wireless systems and about 10 times that of the 700mHz ones used by garden-variety rock concerts—means most pro white-space users will have to deal with an often-strange new world for the immediate future, once that Big Switch in the Sky gets flipped for good and the white spaces go from being a quiet-but-chummy little club to a massive CE acropolis where white space and MySpace collide.
Dan Daley (danwriter at aol.com) is an experienced journalist and author, covering the business and technology of the entertainment industry for over 20 years. His work has appeared in numerous publications, both trade and general interest, including Billboard, The New York Daily News, Mix Magazine, GRAMMY Magazine, American Way, Spin, History Channel, TravelHost, International Business, USA Today, ArchiTech, and many others.
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