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Think Big: Consultant Proposes AM Daytime Power Hike

04.27.2010




Broadcast radio consultant Richard Arsenault has a bold idea to offset electrical interference to the reception of AM radio in the United States.

He is petitioning the Federal Communications Commission to allow virtually all AM stations, if they wish, to increase daytime power 10-fold or, if that's not possible, at least four-fold.

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

Arsenault argues that the 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." In his eyes reception of AM radio is almost useless in many areas.

"Typically, co-channel and adjacent channel interference are no longer the limiting factors to interference-free reception during daytime hours," he told Radio World in a summary of his new petition. "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."

Arsenault says few radios are capable of satisfactory reception under the protected daytime service areas out to the 0.5 mV/m contour that applies to most AMs. "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." 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 suggests that the FCC allow the increases during a five-year window. He also suggests a grace period to allow stations that elect to participate the time to install upgrades. Stations would need only to send a letter to the FCC specifying the degree of power increase and date of implementation. "All future interference calculations could be made utilizing the previous lower power levels of all stations, simplifying future allocation issues."

As to border areas and those where "a salt-water interference path to foreign stations exists," stations could use directional antennas or a partial power increase.

Arsenault 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."

Comment to Radio World at radioworld@nbmedia.com. Contact Arsenault via his website.


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COMMENTS (10)
Anonymous - 05/03/2010
MW has far better coverage than VHF for the same cost. In mountainous areas, an AM station won't want to move to High-HF (with poor night coverage) or to line-of-sight VHF using 10 booster sites (that all have to be maintained) when these restraints can be overcome by using a legacy 575ft tower and 50 kW AM rig with stereo-HD. Also, DRM on HF won't serve listeners as well as properly DSP'ed AM Stereo or iBOC because (apparently) the DRM standard for MW and SW is incapable of stereo. Therefore, high-frequency replacements for AM would not benefit stations or listeners, and the focus of the issue SHOULD be on: -Electronics manufacturers that sell A. Devices which increasingly emit high RF noise levels, and B. AM receivers having crappy sensitivity, no signal processing, and bad audio quality (it's the Year 2010, not 1930, but most AM receivers are deaf to signal, monaural, and muddy-sounding). -Power companies that ignore defective powerlines creating electrical noise, and that overlook buzz-saw style pulse noise entering the power grid from switching power supplies (a blatant violation of Pt-15 when the WHOLE AM band is obliterated 1/4 mile around the lines). Increasing AM transmitter powers may help, but the benefit would be small unless the noise-floor issue was fixed and the FCC did some (terribly-needed) channel reallocations. It would ALSO help if the FCC required the more USELESS talk-syndicators that simply parrot satellite feeds that can be heard on multiple AM channels across the daytime band at any given locale to either A. Provide original programming, or B. Leave the AM dial altogether and give other stations more bandwidth. If AM program content were more diverse, original, and enjoyable (i.e. music and real information) instead of snake-oil ads, sports-talk and right-wing propaganda, far more attention would be paid to AM reception, receiver quality, and interference resolution. In some respect, AM stations have themselves to blame in th

James Johnson - 04/29/2010
If the power companies would comply with Part 15 rules then the noisy power lines would not cause so much trouble. I have considered the idea of using 26.96 to 27.41 MHz for night transmissions of "AM" stations but I think that a VHF Digital band with DRM would be better. Less Power, More Coverage. VHF Digital.

Anonymous - 04/28/2010
Good idea. Let's just allow station groups of seven(7) or fewer AM stations to implement this on their seven(7), or fewer stations. It's about time that the FCC do something beneficial to the public that listens to AM.

Mike Vanhooser - 04/28/2010
Let the well established legacy stations increase power, and let the lower powered, local stations move to a new band at 26MHz (or thereabouts) DRM. Then begin integration of new chips into all new radio receivers which can decode DRM and on a date certain in the future all current stations on the AM band switch to DRM, as happened with TV. That is a transition which makes sense, will work flawlessly but unfortunately doesn't feed the pockets of Ibiquity and their parasites. This is the only workable way to bring digital to the MW band. Otherwise, we might as well as abandon the band, as AM must be transitioned to digital to deal with all the noise.

Anonymous - 04/28/2010
What???? "Let us not forget, as the FCC Commissioner reminded us at the NAB, "All these radio licenses belong to the government"; they are on loan for us to use." Let us not forget we citizens put the government in place and therefor we the citizens (should) own the Government and therefore the licenses - lest you forget.

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