Engineering consultant Richard Arsenault says the biggest problem for AM reception during the daytime “is no longer interference between stations”, as it was when the AM service was established decades ago. The former station owner and consulting engineer says the threat is now “interference from electronic devices and power lines”, and it’s steadily getting worse.  Arsenault suggests at least a four-fold increase in power, and possibly as much as a 10-times hike for some stations.

Power line transmission towers may affect AM station coverage
Power line transmission towers may affect AM station coverage

This is separate from his earlier petition, addressing pre-sunrise authorization rules, on which the commission is taking comment.

Arsenault argues that AM service has suffered serious degradation of coverage from interference caused by new technologies. He cites broadband over power lines, computers, appliances like microwave ovens, energy efficient fluorescent lighting with integrated solid-state switching circuitry “and virtually all other electronic devices and services.”

Arsenault said: “The commission established service contours and interference protection ratios at an earlier time when interference from existing electrical equipment was minimal and interference from digital electronics did not exist. At that time, the protected contours and the interference ratios made sense. Unfortunately, they were calculated without available foresight of the future digital technological revolution.”

“What we currently have are AM broadcast stations adequately protecting each other in the AM radio band, but these same stations are not receiving protection from the intense electromagnetic interference from unintentional sources.” LBA offers a lineup of RF shielding solutions and RF shielding services.  He wants the FCC to rethink its protected service contours: “The sources of electromagnetic interference are part of our current lifestyle and will only get worse.”

Increasing power during daytime hours would solidify daytime coverage of participating stations without altering the interference ratios between them. “I recommend that a ten-fold (10 dB) power increase be adopted. If this can not be achieved, alternately, power increases of four-fold (6 dB) could be adopted and still be significant. Ultimately, anything less than a doubling of power (3 dB) would be almost insignificant.”

Arsenault’s proposal would limit the power hike to daytime hours, at least at first, until nighttime interference concerns could be worked out.

He concludes: “AM radio service will further decline without serious intervention to remedy the interference issue as the ratio of the unintentional interference to AM radio will only increase further with the addition of each new technology. The time to get the static out of AM radio is past due.”

Lawrence Behr Associates can also provide intermodulation studies / interference analysis solutions. Contact for more information.

About The Author

LBA Group, Inc. has 60 years of experience in providing RF asset solutions and risk management for industrial and telecommunications infrastructure assets. The group is comprised of LBA Technology, a leading manufacturer and integrator of radio frequency systems, lightning protection and EMC equipment for broadcast, industrial and government users worldwide; the professional consultancy Lawrence Behr Associates and LBA University, providing on-site and online professional training. The companies are based in Greenville, N.C., USA.

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