03/22/2016

The Society of Broadcast Engineers (SBE[1]) has told the FCC that the regulatory agency needs to take another tack in its efforts to tackle AM revitalization. If the FCC takes the SBE's advice, the result could be less noise in the MF and HF Amateur Radio bands. In comments[2] the SBE filed in response to an FCC Further Notice of Proposed Rulemaking and Notice of Inquiry (MB 13-249) proposing ways to enhance the viability of the AM broadcast service, the SBE said the Commission must "commit to a regulatory plan which, over time, will reduce the levels of man-made noise in the MF bands, and more broadly in the bands below 30 MHz." In comments it filed earlier in the proceeding, the SBE pointed out that "AM radio in particular is susceptible to interference from electronic devices of all types," and that ambient noise on the AM band is only bound to get worse with further proliferation of noise-generating electronic devices, including certain lighting devices regulated under FCC Part 15 and Part 18 rules.

"[T]he only source of regulatory reform that has a meaningful chance to positively affect the noise floor over time are regulations that create obligations on manufacturers and importers and dealers, prior to the point that the consumer or user of the device or system comes into possession of it, and before it is deployed," the SBE said. The SBE said that while the FCC has strongly supported unlicensed low-power RF devices over the years, it "apparently does not have a clear understanding of the aggregate effects" of these devices on the MF noise environment. In addition, the power grid has expanded, imposing its own family of electrical noises on the radio spectrum.

"Much unintentional interference is local in nature, but the cumulative impact can be extensive," the SBE told the FCC. "In the case of power line interference, the impact is extreme on automobile radios, whose travel path often parallels electric distribution and transmission lines." The SBE referenced a consulting engineering firm'sÿinvestigation showing that the signal of one 50 kW station was unlistenable just 4 miles from the transmitter on a car radio.

"The Commission does not now have, and has never had, a complete understanding of ambient RF noise levels and trends over time," the SBE said. "Furthermore, the Commission has uneven regulations and policies governing noise-generating intentional, incidental, and unintentional radiators; and its enforcement efforts in this context have been, and are, both impractical and insufficient."

The SBE urged the FCC to better enforce some existing regulations and develop new ones to address ambient noise in the existing AM band. "It is obvious that any interference management plan?has to be based on rules which limit RF noise before it becomes an issue, not post hoc, and those rules have to be enforced," the SBE said.

As a start, the SBE suggested, the FCC might consider establishing limits on the amount of noise that Part 15 unintentional radiators, such as plasma televisions, can radiate directly. Only conducted emission limits now exist. The SBE also cited "substantial numbers" of harmful interference complaints from Amateur Radio stations, stemming from various lighting devices. Some big box stores, the SBE pointed out, have been selling commercial lighting ballasts to residential consumers. The FCC also should "substantially increase" its enforcement in power line interference cases.

"There are literally dozens of complaints from Amateur Radio operators of severe interference from power line noise annually," the SBE said. "Power line radiation in the HF and MF amateur allocations will, in most cases, directly translate to preclusive noise in the AM broadcast band."ÿ


[1] http://www.sbe.org/
[2] http://sbe.org/sections/documents/FNPRM_AM_Improvement_13-249_20160321.pdf

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