In what the FCC is calling a first, the agency is levying fines totaling $40,000 against four broadcasters using a shared transmitter site for violating maximum radio frequency radiation exposure limits. The transmitters at issue are located on Mt. Wilson, in Los Angeles, Calif.

The commission issued Notices of Apparent Liability for $10,000 each to Telemundo, licensee of TV station KWHY-TV; AMFM Radio, licensee of KBIG-FM; Radio One, licensee of KKBT; and Infinity Broadcasting, licensee of KRTH-FM. The commission said that each licensee was transmitting within acceptable power limits, but "the cumulative effect exceeded the limits established by the FCC."

According to the FCC, its rules establish maximum permissible exposure limits for radio frequency radiation. If the limits are exceeded by the cumulative emissions of multiple transmitters, all licensees whose transmitters produce power-density levels exceeding 5 percent of the exposure limit applicable to their particular transmitter share responsibility in reducing the RF radiation level.

FCC agents who inspected the Mt. Wilson transmitter site, which is located about 100 feet from a post office, found RFR levels 60 percent above the limit. Each of the four cited stations were exceeding the 5 percent limit, and failing to prevent public access to the area. However, the stations did take steps to limit public access shortly after the violation was brought to their attention, the FCC said.

The Oct. 29 issue of TV Technology features a story on the Mt. Wilson project.