NPR joined with the proprietor of HD Radio technology, iBiquity Digital Corp., to propose that the FCC quadruple the permitted digital FM power level. In a statement released today they agreed the plan would protect analog FM broadcasts from interference while significantly improving reception of the digital HD Radio signal — especially by receivers indoors, where the digital signal sometimes can’t penetrate.
Last fall, after other broadcasters suggested a ten-fold power boost for the digital signal, NPR field tests found the larger increase would interfere with regular FM broadcasts.
If the FCC takes NPR's and iBiquity's advice, it would authorize a blanket 6 dB increase, from 20 dBc to -14 dBc. Most stations could boost their digital signals by more than 6 dB, they calculated, laying out the option of greater increases where spacing between stations and other criteria would limit interference.