Noise Is the Big Problem for AM, SBE Argues
It’s time to get tough on ambient noise in the AM broadcast band
and on medium-frequency bands in general.
So says the Society
of Broadcast Engineers. SBE is urging the Federal Communications Commission to
launch an interference management plan for the AM band, “based on rules that
limit RF noise before it becomes an issue, not after the fact, and those rules
have to be enforced.”
Filing comments in the FCC’s AM
revitalization further notice of proposed rulemaking, the society also said the
FCC should study current ambient noise in the MF band, with an eye toward
updating older studies on the subject.
“This will permit
a reasoned analysis of the commission’s Part 15 and Part 18 rules and thus
contribute to a controlled RF environment over time,” it wrote in a summary. The SBE has suggested
that AM broadcasting will never get better in the worsening RF noise
environment in the bands below 30 MHz without some regulatory relief.
Here is the text of the SBE summary, and a link to the complete filing is at the end:
SBE Files FCC Comments on AM Improvement
Society of Broadcast Engineers filed comments in response to the Federal
Communications Commission’s further notice of proposed rulemaking and the
combined notice of inquiry in the AM Improvement Docket, 13-249. Its comments
focused on a single issue first raised in the SBE’s comments filed in the
proceeding in 2014, but not addressed by the FCC in its October 21, 2015, first
report and order: that of ambient noise in the AM broadcast band specifically,
and in the Medium Frequency bands generally. The SBE’s comments note that the
Commission has made, and is currently examining additional short-term
improvements in AM broadcasting in this proceeding. Although those short-term
initiatives may be necessary to help the serious economic conditions for AM
broadcasters, they are not going to lead to any meaningful, long-term
improvement in MF AM broadcasting. To do that, the SBE asserts, the Commission
is going to have to be willing to implement some difficult regulatory reforms
that it has not addressed to date. It must develop and commit to a regulatory
plan that, over time, will reduce the levels of man-made noise in the MF bands,
and more broadly in the bands below 30MHz.
The FCC noted
earlier in the docket that “AM radio is particularly susceptible to
interference from electronic devices of all types, including such ubiquitous
items as TV sets, vehicle engines, fluorescent lighting, computers, and power
lines. The noise on the AM band that is caused by those sources is only
expected to increase as electronic devices continue to proliferate.” The SBE
suggested that this increase in noise is not inevitable. However, it is a
serious and worsening problem. Citing the aggregate effects of Part 15 and Part
18 unlicensed devices, the SBE notes that the FCC does not have any practical
ability to address the interference potential of unlicensed devices past the
point of sale. Reductions in field staff available to conduct spectrum
enforcement have made enforcement in interference cases involving unlicensed
devices unavailable in the future. The only source of regulatory reform that
has a meaningful chance to positively affect the noise floor over time are the
regulations that create obligations on manufacturers and importers and dealers,
prior to the point that the consumer deploys it.
a study by the LBA Group, AM reception is dependent on the desired signal being
typically some 26 dB above the ambient noise level. The AM band is subject to
AM coverage distortion, increasing noise threats, and interference from the
proliferation of wireless systems, electronic devices and low-frequency
radiators that distort AM signals more now than as recently as 10 years ago.
The electric power grid has expanded, bringing noise contributions from corona,
arcing, and other modes. AM stations have increased power to raise their
signal-to-noise ratio in an attempt to preserve their coverage areas, often
interfering with other stations. But there is a limit to power increases, both
economically and technically, and those limits are now reached in many cases.
The SBE argues that AM listeners have media options, and that
RF noise will make them exercise those options. When an RF lighting device or a
Part 15 intentional radiator causes interference to their receivers, AM
listeners receive interference. They will not suffer it; they will simply
utilize different media. The SBE urges the Commission to commence an
interference management plan for the AM band, based on rules that limit RF
noise before it becomes an issue, not after the fact, and those rules have to
be enforced. The FCC should also study current ambient noise in the MF band,
with an eye toward updating older studies on the subject. This will permit a
reasoned analysis of the Commission’s Part 15 and Part 18 rules and thus
contribute to a controlled RF environment over time. The SBE suggested that AM
broadcasting will never get better in the worsening RF noise environment in the
bands below 30MHz without some regulatory relief.
Read the SBE filing in full (PDF).
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