FCC Cites Detroit System For Signal Interference

Washington-MediaOne of Metropolitan Detroit Inc.'s cable signal spilled onto an emergency frequency last summer, threatening aircraft communications, the Federal Communications Commission determined last week in fining the operator $55,000.

The interference constituted a "serious threat to the public safety," the FCC said. It assessed the maximum allowable fine.

The 121.5-megahertz band is reserved for emergency beacons. The Air Force Search and Rescue Satellite-Aided Tracking (SARSAT) system picks up distress signals on that frequency and relays them to the U.S. Air Force Rescue Coordination Center, which responds to flight difficulties.

"A non-distress beacon-or signal interference on the aviation emergency frequencies-can mask or overpower an actual distress beacon by the SARSAT system," said Air Force Lt. Col. Bryan Holt. False signals have diverted search-and-rescue personnel from emergency situations, he noted.

Broadcast signals intrude on emergency channels about once a decade, noted FCC spokeswoman Michelle Russo.

The FCC Compliance and Information Bureau determined MediaOne's signal was leaking on the emergency frequency at 1,416 microvolts per meter on Aug. 9, 1999. Commission rules prohibit cable systems from operating in excess of 20 microvolts per meter at three or more meters from the cable.

Rich Ruggiero, a MediaOne Midwest region spokesman, said the leakage was caused by the closing of old channels in Oak Park, Mich., as new ones were inserted.

"Amplifiers sensed low signals because two channels were still up," Ruggiero said. "The amplifiers boosted the signal, [turning] a tiny leak into a good sized one."

MediaOne shut down the interfering channels before the FCC issued a stop order, Ruggiero said.

The FCC noted that MediaOne complied with the agency's orders. "We have revised [our] approach to wrecking out old cable plants so this kind of thing won't happen again," said Ruggiero.

The Air Force satellite system first picked up the interference on Aug. 5, 1999. Once Media One corrected the leaks, the system detected no interruptions.

MediaOne has 30 days to pay the fine, appeal it or claim financial inability. Ruggiero said company attorneys are reviewing the FCC decision.

States News Service