That's why Temecula, California-based Jeff Dykhouse of WorshipMIX, an AV design and production house, had one of his most recent existential moments when he was approached about designing and implementing a 24-channel wireless system for the school auditorium. Slated for use with the school's theatrical presentations and other events, the system was designed to exist, quite literally, in the eye of a very serious RF storm.
"There are more than 20 TV and radio stations broadcasting from the top of Mt. Wilson at ranges of up to 166,000 watts," says Dykhouse, who chose Shure UHF-R wireless transmitters and receivers for his assignment. "Using Shure's Wireless Workbench on my Mac, I turned on my receivers and let the software randomly assign frequencies for my 24 channels. More than two-thirds of the channel meters were pegged from interference, and I hadn't even powered up a single transmitter of my own."
Working with Jeff Suchy of Apex Audio in Huntington Beach, Dykhouse chose Shure UHF-R in part because of an inherent design that enables users to place transmitter frequencies in close proximity to one another, a vital consideration given the crowded nature of the RF environment.
"We also gave additional value to the Shure product based on its auto frequency locator, which seeks out open space in the spectrum based on information gathered from a central database as well as what it finds in the environment itself," Dykhouse explains. "I tried it both ways and still couldn't find a home for all of our transmitters; there was still interference. One of the biggest problems was that some of the interference wasn't continuous."
In Dykhouse's Plan B of attack, he called on another Wireless Workbench feature that enabled him to scan over long periods of time. Letting the software analyze the environment for four hours, he used the collected data to go back in and close the gaps.
"The last hour or so didn't reveal anything new in terms of interference, so I manually placed my transmitters in the only available spaces and things began working," he says. "Jeff Suchy chose two bandwidths of operation. When you see them mapped out on Wireless Workbench, they look like the craziest choices available - open spaces were few and far between.
"There was method to his madness, however. We designed the system prior to the DTV transition on 12 June. Once analogue TV broadcasts were suspended, the blueprint took on a clearer face. In the meantime, pre-transition, the school put on a presentation of Sweeney Todd using 20 of the 24 UR1 bodypacks we provided, and the play navigated its entire run without so much as a hiccup."
(Jim Evans)
