 Previously, in 1998, the FCC rejected an ARRL petition for LF allocations at 135.7–137.8 kHz and 160–190 kHz.In 2002, indications from the FCC had been that 136 kHz privileges would be authorized soon.On 14 May 2003, however, the FCC declined to grant these privileges citing concerns over potential interference with power line communications (PLC) systems operating unlicensed under Part 15 which are used by electrical utilities to send control through the power grid.