Intercom Trends: Spectrum Consolidation Moves Solutions Into WiFi Range

The White Spaces issue consuming much of the wireless world’s attention for the past two years is ostensibly about allocating more spectrum to consumer wireless devices. But the collateral effects for sports broadcasting have been significant. With less overall spectrum available for use, the critical intercom sector is affected: the communications channels that are used by coaches, players, and broadcasters and create an invisible and complex web around every match in the major leagues, NCAA sports, and, increasingly, mid-level college and high school sports.

Andy Cocallas, owner of Game Time Communications, an RTS/Telex dealer and wireless-intercom consultant, has worked on intercoms at all 32 NFL stadiums, including regularly for his hometown Chicago Bears. He notes that the amount of available spectrum for intercoms has been cut by at least half as a result of recent FCC reallocations.

“Let’s say we use about 250 frequencies in the course of an NFL game — maybe 50 for coach-to-coach and coach-to-quarterback communications and so on,” he says. “Before the recent FCC changes for HDTV and national security, we could operate above 698 MHz. Today, we’re limited to below that. There’s been a lot of shrinkage of the [spectrum] field.”

Cocallas also notes that a large chunk of the UHF range — specifically the 700 MHz range — has been reallocated to national-security applications, truncating the frequency band that most users consider the best-sounding and most reliable. “UHF definitely gives you the clearest audio and has superior ability to deal with crowded RF environments,” he says, “so you’re more likely to find clear channels.”

That’s propelling a cautious transition to WiFi-based wireless intercoms using the 802.11n standard. That standard does present challenges, including an increase in signal dropouts and the fact that consumer devices also heavily use it. It’s also been widely reported that WiFi has particular issues with domed stadiums, due to multipathing problems caused by proximity to large numbers of other WiFi devices and cellphones in the same venue.

But Cocallas points out that WiFi is also less location-dependent than UHF and is considerably less expensive than UHF systems, allowing it to move deeper into college and regional sports markets.

In smaller stadiums that don’t have Chicago’s RF challenges, such as most high schools and NCAA lower-division colleges, he has found that a high-quality WiFi system often works fine. “A big part of what I do in those situations involves the Telex Legacy system,” which uses 802.11 wireless LAN technology and is encrypted with 64-bit DES, he says. “It’s a good little out-of-the-box, inexpensive, easy-setup system for up to seven wireless coaches, and you can easily add a few extra coaches in the booth with some inexpensive Telex cable splitters to make a great nine-coach high school system.”

John Kruman, sales manager for government and mobile productions for Germany-based Riedel Communications in the U.S., predicts that, despite its limitations, wireless intercom operation is going to become more common in sports broadcasting. He points out the use of Riedel’s Acrobat system at the Minnesota Twins’ Target Field and other sports venues and events.

However, because of spectrum reallocation, anything wireless will have a higher uncertainty factor, thanks to ongoing and less-than-predictable spectrum sell-offs by the FCC. Thus, he says, more far-reaching solutions will have to include other types of technologies, such as the Audio Video Bridging (AVB) set of technical standards, which provide the specifications that allow time-synchronized low-latency streaming services through IEEE 802 networks. Riedel has joined a growing number of audio companies in AVB trade group the AVnu Alliance, recently introduced its first AVB product, and is emphasizing that its intercom system has 100%-digital operation.

“The fact is,” he states, “while wireless has its challenges, the changes in spectrum that are creating uncertainty in wireless intercom operation are also creating huge opportunities.”

Vinnie Macri, product marketing manager at Clear Com, also sees increased interest in his company’s 900 MHz and 2.4 GHz wireless intercom products. He acknowledges WiFi’s problems but says there are solutions, such as built-in frequency-hopping that moves the signal every 200 ms within the 1.5-MHz-wide slice of spectrum in which it operates.

There’s still resistance to upper-spectrum WiFi intercom solutions, however. Macri says Clear Com has been doing seminars on the topic at trade shows, trying to lay the format out to potential sports-broadcast users and others. In some ways, the changes to the spectrum and the responses of both manufacturers and users — the former’s development and marketing of more upper-frequency wireless solutions, the latter’s growing awareness that alternatives are needed as UHF spectrum disappears — are creating a scenario not unlike what console manufacturers have experienced in recent years: technology changes move an industry sector further into the digital domain and, as a result, open the sector to more competition and innovation, as well as uncertainty.

“In the end, that’s a good thing,” he says. “But it’s going to take time.”

The next generation of wireless intercoms may take a matrixed approach, not unlike the move to multipoint routers in remote trucks. Cocallas says that, although adoption of that is a few years away, it will bring with it more granular level of control over systems, such as the ability to create larger networks and allow individual control over the volume level of every point on the network.

It’s also possible that intercoms will become a completely IP-based proposition at some point, which would help put spectrum issues further behind it. And all of these challenges underscore just how critical the invisible intercom network is to sports broadcasting.