The National Association of Broadcasters and the Association of Maximum Service Television, Inc. (NAB and MSTV) filed reply comments in the FCC Notice of Inquiry on carrier current systems and broadband over power line (BPL). The comments note that BPL equipment operating in the 1.7 to 80 MHz range "pose serious risk of interference to television Channels 2-5, especially the 11 stations currently transmitting a digital broadcast signal on these channels, as well as several stations who are likely to elect lower VHF channels at the end of the digital television transition." NAB/MSTV said the FCC should limit BPL use to frequencies below 50 MHz.
The reply comments also noted that BPL proponents Ambient and Ameren "did not offer a technical solution to mitigate interference, aside from ceasing transmission once notified by a licensed radio service that interference has occurred." They also point to an acknowledgement by the Information Technology Industry Council that, "The potential interference from transmissions over power lines will be propagated by these extended wireline networks or antenna. In fact, the radiated emissions from these extended networks are likely to propagate throughout entire neighborhoods causing potential interference to many electronic devices and licensed services throughout that service area."
NAB and MSTV dismissed comments by some proponents arguing that they have received no complaints of interference during experimental field trials and that this is evidence that BPL systems will not cause interference generally. "This argument is flawed. It is a well-known fact that although consumers may observe that something is wrong with their reception, they do not recognize it as interference. Even if they do, consumers may be unable to identify the interference source. In the case of over-the-air broadcasting, consumers frequently change the channel or turn off the receiver. The Commission should not use the 'lack of complaints' as a basis to authorize BPL. Instead, the Commission must place the burden on the BPL proponents to demonstrate with relevant scientific measured data that it will not cause interference to licensed radio services. At a minimum, the Commission should settle issues regarding measurement procedures before moving forward in this proceeding. It is vital that all measurements, particularly radiated measurements on Access BPL systems, are uniformly conducted. Moreover, the Commission should require all operating BPL systems to submit actual measured data as a condition of their experimental licenses."
