Text has been updated to clarify that the comments were submitted on behalf of NEMA Lighting Systems division member companies, not necessarily those that make electric motors or other industrial products.
NEMA included diagrams such as this one detailing natural and man-made noise emissions. This is from a 2003 study “Man Made Noise Measurement Program” published through Ofcom, the communications regulations agency for the United Kingdom. U.S. broadcasters often complain about noise on the dial from lighting fixtures, electric motors, and various consumer and industrial products. But what do people who make some of those devices say?
Lighting system member companies of the National Electrical Manufacturers Association don’t think the noise issue is so clear-cut. They want to see a careful study of the question.
NEMA represents about 400 electrical and medical imaging manufacturers, including members that make industrial lighting systems. It filed comments to the Federal Communications Commission advisory group in the technical inquiry about spectrum noise that we’ve been telling you about.
Its position can be summarized in its opening paragraph: “Is there a noise problem? This is a controversial question.”
The association acknowledged that the level of man-made noise from consumer electronics is unprecedented. Yet it also said interference is a regular design consideration for manufacturers, and that digital electronic devices use less energy and tend to be covered under federal EMI regulation as digital devices.
“The digitalization of consumer electronics, the transformation of the TV broadcasting from analog to digital, and United Sates Department of Energy minimum energy conservation standards imposing significantly lower power consumption limits on consumer electronic goods may have resulted in lower man-made noise levels for some products,” it told the advisory group. “This seems supported by … findings from several researchers indicating that consumer electrical environment noise has been reduced.”
It pointed to a 2001 report published by the United States Department of Commerce Assistant Secretary for Communications and Information, reporting a decreased noise floor level in residential environments and no change in the noise floor level for the commercial environment over 25 years. It analyzed man-made noise power measurements at VHF and UHF frequencies.
NEMA also said questions about interference and proximity can be hard to answer because of the many possible scenarios. A consumer might place a small TV set on the top of a microwave oven and experience harmful interference, “but the problem may be quickly solved by placing the TV set a few feet away from the microwave oven, rather than through more stringent emissions standards. Similarly, AM radio reception will always have additional noise for a consumer living close to a power distribution line.”
Further, older reports often referenced interference from analog TV services that don’t exist anymore. And some studies are from outside the United States, where electrical and construction codes differ, so it’s unclear how findings may relate to the U.S. electromagnetic environment.
But, NEMA continued, “We cannot ignore concerns from other professional interest groups. Whereas average noise figures describes noise present at least half of the time in half of the examined locations, it is unclear if this figure addresses the concerns of a specific location and a specific time of day. Additionally, digital consumer electronic devices produce limited emissions; thus frequencies that were silent in the 1960s or 1970s may not be silent anymore.”
It feels that because data are contradictory and there’s a lack of relevant U.S.-based research, “It is important that a research study be implemented to identify if a noise floor increase has occurred and, if so, what the magnitude is for different environments and frequency ranges.”
The association said the frequencies of most interest are probably 450 kHz to 1 GHz to start, but that the FCC should extend the survey up to 1 THz to “include all modern communications.” It also laid out thoughts on whether to rely on traditional metrics such as White Gaussian Noise (WGN) and Impulsive Noise (IN).
What does NEMA think about the possibility of stricter emission standards for products? Its filing didn’t explore that, but the opinion of its members might be guessed from another answer. If incidental radiators are indeed found to be a concern, NEMA wrote, government can contribute through research to understand the phenomena and address specific industry sector concerns. “Industry and civil society could engage in training and education for consumers to better understand what man-made noise is, how specific consumer devices mitigate noise, and to further spread best installation practices concurrent with the National Electrical Code.”
Broadcasters though would likely be unsatisfied with more research and consumer education alone. The National Association of Broadcasters wants the commission at least to conduct a “comprehensive review” of current limits, to set emission limits for devices operating on the AM band and to clarify the kinds of good engineering practices that should be followed by makers of electronics that cause so much noise. NAB said failure to take aggressive action “risks devaluing licensed spectrum and drowning licensed users in a sea of noise.”