Simple, Reliable Interconnects At An Outdoor Stadium

by Keith Clark
Editor, Install Sound

Establishing permanent audio (and other) cabling and interconnects at the infield of an outdoor stadium can be tricky business.

This problem can be addressed a number of ways, as a recent Syn-Aud-Con listserve thread on the topic showed. But many of the proposed solutions were countered with drawbacks.

For example, what about a watertight interconnect box mounted flush in the infield ground, linked to the system control position (usually on the press level) via cables buried in sealed conduit?

For football, a snake linked to a watertight box under the grandstand meets all cabling needs; for track, two pedestals meet interconnect needs from the infield.

Good thought. But remember, the box is only watertight as long as the lid is sealed. What if it rains during the event, when the lid is open to accommodate interconnect? Serious threat of water damage... Also, torrential spring downpours can produce standing water both surrounding and maybe even topping the box. And, what about build-up of condensation, dripping into the interconnects?

One idea recently offered by John Looby, system engineer at Eastern Illinois University (EIU), holds a lot of logic. And, it's already been proven to achieve the desired results for the past two years - simply and reliably.

O'Brien Field, an outdoor football and track facility on EIU's Charleston, IL campus, underwent a renovation two years ago. During the planning stage of the renovation, the tech crew was asked to supply an infield interconnect solution.

John picks it up from here:

"Our stadium is used for both football and track. We quickly discovered the solution for one sport may not be the best solution for the other sport. To accommodate each sport, different solutions were needed.

The two removable pedestals, in tandem with a watertight lighting box, provide "above the water line" cable and power interconnects during track season.

"For football, needs are intercom and public address system access. We used a watertight box under the grandstand, near the field, and on game days, a snake runs from this box, across the track, to the infield. A heavy-grade plastic mat protects the snake. At the infield, the snake's interconnect box is placed under a team bench, protected from moisture by a plastic bag covering.

"For track, needs are public address, video, future data, and power. We decided to use an underground lighting box, set in concrete inside the track, as the starting point for this interconnect solution. The square box in the middle of the pedestals contains a variety of cables, including four balanced audio lines, two coaxial cables, a 25-pair telephone cable and one pull wire.

"Our electricians attached elbows to each end of the box, each with threaded 3-inch fittings flush with the concrete. These accommodate two plastic pedestals that can be easily attached (screwed on) and removed.

"The pedestals, about 2.5-feet tall, are painted yellow, a request by the grounds crew for better visibility so they aren't accidentally mowed over. The pedestals are installed each spring and removed after the Illinois High School Association track championship meets in May.

"When installing the pedestals, a 'wet vac' is used to remove water from the underground box, the seals are checked, and the lid is reinstalled just before the spring rains.

"One pedestal is for power, the other includes a covered weatherproof audio panel with two XLR jacks, linked to the audio cables in the box. The next most likely addition to the pedestals will be telephone jack(s), which are in the highest demand.

"After experimenting with a couple of solutions to provide track meet finish results more quickly from the field to the PA announcer's booth, our athletic department settled on using fax machines. Results sheets are faxed via a machine on the field to another machine in the announcer's booth.

"The coaxial lines, for video, were used for the first couple of years but are not currently in use. And, it can't be seen on my photos, but the bottom of the weatherproof audio panel include 1/2-in threaded holes. We've been feeding temporary cables through these holes, and wrapping the connectors in plastic.

"This solution has worked out well for us, meeting the specific needs of two very different applications on the same site. The pedestals have been quite convenient in addition to placing power and the audio interconnects above the threat of water/rains."

(Editor's note: Thanks very much to John for providing these details and photos.)