LOS ANGELES—As broadcasters experiment with new methods of video backhaul to the station from their ENG crews—including bonded cellular and wireless public networks—the means by which audio is captured on remotes remains, so far, largely unchanged. Meanwhile, FCC rulings over the last several years, and planned for the near future, are altering the usable RF spectrum.
Wireless microphone technology for ENG is still typically based on an analog platform and UHF frequencies. “We view UHF television spectrum as being the best suited for ENG applications,” commented Karl Kussmaul, senior product manager for Sony Electronics. “We wouldn’t promote the use of 2.4 GHz systems, like our new DWZ, for that purpose.”
FEATURE, FREQUENCY OPTIONS
UHF offers advantages for broadcasting, where there is zero tolerance for unreliable operation, he continued, including its abilities to pass through structures, distance capabilities, and reliability.
That said, there have been some recent advances. “Sony is unique in that we’re using digital modulation for transmission,” said Kussmaul. “In our latest ENG product offerings we offer both analog and digital.”
Sennheiser’s ew 100 ENG G3 system Sony’s professional entry-level product, the analog UWP system, has a street price of about $500, he noted. “In digital we have our DWX series ENG wireless,” which covers an RF bandwidth of 72 MHz or a dozen TV channels.
As a manufacturer of more than just audio products, Sony is also uniquely able to integrate its DWX system into its XDCAM cameras. “Our slot-in receiver can be installed inside the camera in such a way that there is no exterior cabling and allows for an intelligent user interface,” Kussmaul said. “The video shooter, while looking through the viewfinder, can manipulate the control settings of his wireless system.”
Shure offers three products suitable for ENG, the UR5 portable receiver, the UR3 plug-on transmitter, and the UR1H, a 250mW transmitter that offers long distance coverage. Broadcasters need frequency options, and these analog UHF products support 2,400 selectable frequencies across a 60 MHz bandwidth.
“It is one of the few products we make that is available in the 944-952 MHz band,” said Chris Lyons, technical & educational communications for the Niles, Ill.-based company. Although narrow, that band is set aside exclusively for radio station studio-to-transmitter links.
“Any broadcast engineer in a particular town either knows, or could find out, who is using which frequencies for STLs,” Lyons continued. “Those are usually pretty high powered, 10 or 20 Watt, and normally very directional. So the chance of interfering on the ground with a low power wireless mic is pretty remote.”
Azden Corp.’s top of the line broadcast mic system in the U.S. is its 1201 Series, according to Lewis Gerr, western regional sales manager for the Franklin Square, NY-based company.
Azden’s analog UHF system is popular for teleproduction and ENG. “I would say 90 percent of systems out there are used by newsgathering organizations and other field teleproduction. They want something high quality but they don’t want to spend a fortune, and they want something reliable that’s beefy, too,” he said.
A major flagship TV station in Los Angeles is the largest customer of Azden’s 1201, Gerr added. “They looked at it and said, ‘It works for us, why should we spend three times the amount of money to get the same results?’”
Sennheiser’s ew 100 ENG G3 system, which includes bodypack transmitter, handheld transmitter, plug-on transmitter and camera receiver components, operates across 1,680 frequencies and a 42 MHz bandwidth. The ew 100 ENG G3 system has been shipping since mid-2009.
In addition to banks of presets, the system includes a provision for the user to freely program in 25 kHz steps. In the U.S., where wireless systems may operate from 470-698 MHz, or TV channels 14 through 51, the system is offered in three frequency ranges: A (516-558 MHz), G (566-608 MHz), and B (626-668 MHz).
LOW-END UHF BAND
Kussmaul believes there is a trend for broadcasters to focus on the low end of the UHF spectrum, from channel 14 through 20. “That spectrum is desirable because it offers them protection from consumer devices that will be utilizing the UHF TV spectrum,” he said. “The consumer devices that will be rolling out will be operating from Channel 21 up to and including Channel 51, treating that entire spectrum as white space.”
The 900 MHz unlicensed band and 2.4 GHz band are all well and good, but products operating in those ranges typically support limited RF systems. “The 900 MHz product that we sell, for instance, lets you use five systems; the 2.4 GHz system, the GLX-D, is limited to five,” said Lyons.
“Our ULX-D systems can do up to 17 in one TV channel in normal mode, and up to 47 channels in the high density mode,” he added. Being relatively new systems, it remains to be seen if they will be widely adopted for broadcast, Lyons said.
In addition to spectrum in the 900 MHz band, Kussmaul observed that there are other bands available for the operation of wireless audio equipment: “There’s now a new system in place whereby the first free unoccupied channels below UHF Channel 37 and the first unoccupied channel above 37 are, in major metropolitan areas, exclusively reserved for wireless microphone use.”
FCC policy has established databases administered by Spectrum Bridge and Telcordia that enable wireless mic users to register and protect their equipment from interference from unlicensed TV band devices. “You can type in your address and see what are the two channels that are exclusively reserved for wireless microphone use in your area, as well as other unoccupied TV channels that are available to use,” said Kussmaul.
Consumer TVBDs, slated to begin rolling out this year (there are a couple of one-off scientific devices already in operation), could potentially start crowding the available spectrum. With that in mind, said Kussmaul, “Moving forward, a desirable aspect of a wireless system is being able to select from a larger number of frequencies,” offering the user more choice and flexibility.
