Antenna placement at the new Denver International Airport is on hold until carriers can convince airport authorities that additional sites won’t cause interference.
“We didn’t spend $8 million building a radio system for this airport to have anyone come in and interfere with the operational safety of this facility,” said Dave Smith, assistant deputy manager for DIA management information systems.
DIA was designed in 1989, before 1900 MHz spectrum became commercially available. Its designated antenna farm is three miles away from the main terminal building. Even 800 MHz cellular carriers, which enjoy greater propagation than 1900 MHz carriers, have found the placement insufficient.
An additional problem may be the green-tinted glass installed throughout the city’s $4.2 billion facility. The glass is loaded with silver oxide, which interferes with radio transmissions.
The city, which owns and operates the airport, isn’t about to make any quick adjustments to its secure environment. An intermodulation study by an independent firm is scheduled to begin April 21.
The DIA radio system operates in the 800 MHz range and was built by Ericsson Inc. The radios are used by the control tower, pilots, baggage handlers, staff loading the planes, snowplows on the runway, and personnel throughout the main terminal and concourses.
The network is the communication heart and soul of the airport and can’t be compromised to solve the problems of commercial wireless carriers, Smith said.
The airport opened in 1995, and three carriers have installed antennas at the farm: AirTouch Communications Inc., AT&T Wireless Services Inc. and Nextel Communications Inc. All systems operate at 800 MHz.
The three PCS operators with Denver licenses are Sprint Spectrum L.P. -which just launched airport-less service in Denver-Western Wireless Corp. and NextWave Telecom Inc.
Sprint and Western have made their plea to airport authorities: with systems at 1900 MHz, they need more sites, in locations other than the designated farm.
“They asked us to let them install the antennas and if there’s a problem, they’ll change it,” Smith said. “I can’t do that. We have to make sure this facility is secure. We can’t have people up on the roofs. We can’t have towers out where a plane could hit them. We can’t have my workers experience an umbrella effect and miss a critical message. That could be catastrophic. We have the higher priority here.”
Smith said DIA acquired all the frequencies for the airport region from the Federal Communications Commission when the airport was being constructed.
Last summer, DIA hired Ericsson to do an intermodulation study. But the Denver carriers were not satisfied with those results, Smith said, possibly because “that’s who we bought the radios from.”
The fully electronic underground train system also uses 800 MHz radio for emergency communications.