I Can’t Hear You Any More! AM Radio’s Big Problem
(You can read the sequel to this blog here.)
Recently the growing crisis concerning man-made noise and AM radio broadcasting has come to the fore and is now provoking much discussion. This is not to imply that AM broadcast interference problems are something new under the sky. This problem has been growing in severity for decades, and it affects more than just AM radio itself.
LBA’s CTO, Dr. Chris Horne, has made some important presentations about this problem, and a summary of his views has recently been published in the LBA Group blog pages. Now the Old RF Curmudgeon has been prodded to stick his beak into the smoke cloud again, and this posting will contain his views and suggestions about the problem.
What Do I Know About Broadcasting and RF Noise? The Curmudgeon has always been interested in broadcasters, the broadcast industry, and broadcast engineering. He has had many friends who were broadcast engineers, but so far he’s successfully managed to avoid actually working in the field. Additionally, he’s been a listener to AM radio since the “Golden Age of Radio” in the 1940s, although much less so now for AM than in earlier years. In general, he agrees closely with Chris Horne’s conclusions and recommendations. The problem of man-made noise that afflicts AM radio broadcasting, both technical and economic, are very real and very current.
But, by means of viewing the worsening noise problem from a different perspective, gained from his experience working in the utility industry, he is able to bring some different insights to the discussion. And that is the purpose of this posting.
We are all more than abundantly aware of the noise contribution from human activities to the MF and HF spectrum. The Curmudgeon’s own home is in the center of a large metropolitan region, surrounded by miles of houses, industrial parks, and businesses. Man-made RF noise of various kinds is a constant limitation and irritation at his house, as it is in most population centers. And it has been a daily problem. Except, that is, for one afternoon a few years ago when a major electrical transmission network fault resulted in the electrical power supply to the entire region failing suddenly, and it was at least twelve hours before power was restored.
The Curmudgeon’s home electronics are floated on auxiliary station batteries under perpetual charging. Thus, as soon as the long-duration failure was identified on that memorable afternoon and after his home was secured, he immediately began listening to the traffic on MF, HF and VHF (both Amateur and commercial) bands. The HF noise level, typically at about S5 to S7 (S9 = measured 50 microvolts at the receiver input terminals), dropped to a level that did not deflect the receiver’s S-meter, even with the natural atmospheric noise remaining. That afternoon a number of stations, both broadcast AM and others, were heard at the home location that had never been heard before.
What Is This AM Noise Problem? The increasing AM radio reception problem is undoubtedly produced by man-made electrical noise. (An excellent primer on such noise is at http://www.arrl.org/power-line-noise). Part of the noise is contributed by the electrical power distribution network and much of the rest by large power-consuming devices. In that the costs to the consumer of electric energy are rising (in most areas of the country), it seems likely that many of the (inefficient) legacy industrial devices are being slowly replaced by newer, more efficient (and lower noise-producing) systems. Here economics should drive the improvement in RF noise reduction, although there is probably not much hard data to show this yet.
The power distribution networks; however, are something that the Curmudgeon can speak to. Dr. Horne calls for much stricter FCC enforcement of the Part 15 noise limits for distribution networks. Setting aside the question of whether the FCC will ever have the resources to do this, the Curmudgeon offers his views about what, through his experience, he thinks the utility industry response to this challenge might be.
First, it is necessary to differentiate among the types of electrical utilities. There are private corporations (investor owned utilities, “IOUs”), local government-owned utilities (“munies”), and independent non-profit cooperatives (“co-ops”). The Curmudgeon can speak most comfortably about the IOUs, for which he twice was a staff engineer.
A sustained, comprehensive FCC Part 15 enforcement action will present an impossible dilemma to IOU executives. On the one hand, their public image in the community as a regulated monopoly is severely threatened by any federal government enforcement action launched against their company. On the other hand, they may not be able to bring their networks into reasonable, not to mention full, compliance. Let’s look at both sides of this.
For historical reasons, electric IOUs typically do not enjoy high public regard among their customers. (Perhaps surprisingly, the natural gas IOUs enjoy much better support with the public than do the electrics.) Any kind of federal enforcement action against an IOU is going to be taken by its customers as some sort of “indication of malfeasance” on the part of the utility. And most of the public doesn’t distinguish between the FCC and FERC; it’s “all the same” to them. Executives who are presented with an FCC-issued Notice of Apparent Liability (NAL) will scramble to comply and thus to keep their company’s name out of the news. But can they actually comply? We’ll get to that question in just a moment.
It’s not clear how the munies would respond to an FCC NAL. The local governments which own them probably would not feel as threatened by it as would the IOUs. The co-ops, on the other hand, would probably be paralyzed by a receipt of an NAL, but would possibly try to respond to it in some manner.
Looking at RF Noise “On the Ground” - The Curmudgeon is a customer of an IOU that is significantly ahead of much of the rest of the industry in its willingness to try to solve RF problems of its own making. They have a full-time, dedicated RF interference (RFI) troubleshooter with his own company truck, with company-paid training provided by recognized and certified professional organizations, and with professional-grade measurement tools. He accepts customer complaints directly from the public, and he is self-dispatched. In contrast, many other IOUs have no such staff; some contract out this kind of investigative work to non-employee part-timers; others do not respond to noise complaints at all (“until their hardware explodes!”).
Even with Good Equipment, Staff, and Intentions, Can the Utilities Solve the Technical Problems? The Curmudgeon has had a long running electrical arc problem near his house which paralyzes MF/HF reception from time to time. The utility’s troubleshooter (who, by now, is a personal friend!) has come out four different times, and together with his professional tools, we have hunted for the arc. We just can’t pin it down. It’s too complex! Given that the company has hundreds, if not thousands, of miles of overhead distribution lines, and thousands of poles with aging insulators and loose, rusty metal hardware, can the companies even locate all the sources that will contribute to the excessive noise level?
Again, assuming that the utilities accept the challenge of cleaning up their own nests, they cannot possibly do so with their present staffs. Their staffs, both the RF troubleshooters and the field maintenance crews, would have to be greatly expanded. That means there would be an increase in the utility’s operating costs, and these higher “costs of doing business” will be rolled into their rate-making cases presented to their public utility or public service commissions. Ultimately these increased costs will be passed along to the consumer.
And the consumer will promptly revolt against the increased rates. What is he getting for his additional payments? A cleaner RF spectrum? He has no idea what is an “RF spectrum” or why it needs to be cleaned up! Material aid to the AM broadcasters from the rate payers? “Let the broadcasters pay for that!” So, by analogy to the Los Angeles air pollution situation, “the problem will not be seriously attacked until the day when gasoline-fueled motor vehicles in Los Angeles can no longer run using the dirty local air for combustion.” When an important somebody’s ox is sufficiently gored, only then there will be some action.
So, What Are the Engineering Solutions? In the Curmudgeon’s view, there is not a viable long-term solution (technical or economic) for reducing or eliminating power-grid electrical noise generation. Photovoltaic energy-conversion systems with greatly increased photon conversion efficiency would certainly help, but unless on-site energy storage is authorized, the power grid still remains. And it will take perhaps another human lifetime before PV generation becomes a majority energy source. A reasonable alternative might be neighborhood-scale gas turbine electrical generators, fueled by abundant and cheap natural gas. This could result in both the local distribution of power at the 240 volt AC level (minimizing arcing) and the diminishment of the use of the remaining grid. But this is, again, a more than one human lifetime conversion process.
So, the Curmudgeon doesn’t believe that there is an overall long-term solution within the utility industry for the AM broadcast noise problem. The problem is just too vast and too deeply rooted to be attacked in a consistent and ultimately successful manner.
But Dr. Horne also presented some other ideas as well, which ideas are well worth considering. The concept of using synchronous detection and DSP circuits for “modern” AM receivers is very compelling. These are ideas that are fairly simple to implement and are long overdue, but it’s not really clear yet how to “prime the pump” to get this started.
Similarly, the idea of moving AM broadcasting fully into the digital age, even with a resulting slight reduction in theoretical signal coverage range, would also provide some benefit. However, given the current IBOC AM system (that’s “In Band Out of Channel!”), to make a successful transition might well require changing the traditional 10 kHz AM channel raster to 20 kHz spacing, and that might be nearly impossible.
The Curmudgeon certainly does not favor moving to higher authorized AM transmitted power! That will just lead to a “power level arms race,” and he has a gut-level feeling that the RF spectral problems resulting from a power increase would be magnified at an intensity proportional to the square of the (increased) power level! Will Chicago, for example, achieve a net benefit from having half-megawatt AM broadcasters? Or would AM radio there be even worse after the transition?
The industry could consider some sort of “suppressed carrier” transmission system (SSB, DSB, ACSB, or others) in an attempt to push all the available RF energy into the sidebands - Yet another “power increase.”
Who Are the Players with Skin In the game? It’s also necessary to look at the various “players” who have to cooperate in order to solve the problems. There are probably four classes of “players” involved with this problem: FCC, utilities, other industry, and broadcasters. In the Curmudgeon’s view, based on more than thirty years of observation of the FCC, the Commission will not lead the charge for a cleaner spectrum. They don’t have the funding, they are under too much political pressure from high dollar industries (via the Congress), and they have already shown their disregard of the broadcasting industry through their TV spectrum- raiding proposals. Someone such as Commissioner Pai may stick around the office, waving the banner for a “brave and independent (AM) broadcast service,” but the Commission will launch no significant initiatives and the FCC staff will forever “just try to make it through yet another day.”
The power utilities will not, absent overwhelming counter-force, do much toward cleaning up the RF spectrum. The economic costs of doing a “best engineering practice” job of this kind are hugely beyond what the industry can afford, either from its own capital funds or through increased energy costs for the consumer. Unless there is a direct, sustained, and overwhelming regulatory initiative directed at them, we probably are currently at about the best level of mitigation by them that is feasible.
There is a glimmer of hope in the “other industry” area. Lighting, home appliances, and digital devices are areas where improvement is possible. In the overall scheme of things, this won’t improve RF pollution all that much, but at least there is a possibility for doing something.
However, especially in the area of digital devices, the enforcement needs to be greatly stepped up. There are far too many instances of manufacturers “hand constructing” a few prototype samples to send to the independent Part 15 testing and certification labs, receiving their certificates, and then stripping out the shielding and bypassing before launching the Asian production lines. The HF background spectrum today sounds nothing like what it was 30 - 40 years ago!
The AM broadcasters are, largely but with exceptions, low-budget operators with no enthusiasm or cash to renovate either their physical plants or their programming. The Curmudgeon once asked the RF engineering supervisor for a local network-affiliated TV/AM/FM combo whether their (first tier) AM station made any money for them. His answer was “depends upon whether or not we carry the radio broadcasts of the local pro football team. In the years that we have football, the AM station turns a profit.”
From the few station owners that the Curmudgeon has spoken with, and from reading about the misadventures of Clear Channel, the Curmudgeon believes that many station owners are nearly broke, dispirited, unimaginative, and highly adverse to change. “We just want to keep doing the same things, in the same way as we’ve always done them, and we hope to turn a small profit.”
That’s truly unfortunate because, in his view, their only hope is to change! Today’s AM broadcasting isn’t working — for a majority of the stations. Clearly something new has to be tried. By basting the current plethora of noise problems with the sauce of owner intransigence, a sure and certain process is created for catalyzing the swift demise and burial of AM broadcasting!
What, There Are Other Problems? The Curmudgeon believes, as noted above, that most of Dr. Horne’s proposals are good ones, and that they will help to the extent that they can be implemented. But, regrettably, they do not solve all, or even a majority, of the problems facing traditional AM broadcasting. And we’ll note here two such additional problems that Chris didn’t deal with, in addition to the third problem already noted above about insufficient transmission bandwidth for a new digital broadcast service.
1. The proposals as described do not address the mess that has historically resulted from a lax, piecewise geographical allocation of frequencies and power levels. There is a huge inefficiency in the way that the allocations have been historically made, compared to a rational, one-time, a priori re-allocation that could and should be done. Under a rational allocation system, there should be very little need for the “six tower DA array” kind of license.
But the present AM broadcasters will scream, “Doing a nationwide re-allocation will cost a bloody fortune! We don’t have that kind of money!” Perhaps true, but consider the converse: continued deterioration of the Service under present conditions, followed by cascading bankruptcies. The owners have to do something; the present course isn’t tenable.
2. The other problem is not addressed at all by the Horne proposals: the “nighttime MF extended propagation problem!” The nightly disappearance of the ionospheric D-layer presents an insoluble problem for AM broadcasters. Fundamentally, the Service can never reach its full potential as long as it remains on its historical founding band! There is no technological or regulatory solution for this.
And this, after all the verbiage, takes us to the Curmudgeon’s original restructuring proposal presented in a previous blog post: let the present AM broadcasters grab some low VHF spectrum while it is still available, go digital on the new spectrum, and abandon the intractable MF band. If the present AM outlets should eventually morph into being the operational equivalents of today’s FM radio stations, that’s OK too.
To stay on the MF band is to continue the slow march toward oblivion. The MF band, in the founding years of the 1920s, was an historical necessity. Today it is a major liability. Evolve or die!
The Old RF Curmudgeon Signing Off! What we have here, it should be clear, is a major societal-level problem. The means are available to work our way past it, and the biggest uncertainty remains whether we have the drive and the fortitude just to do the work. The Curmudgeon certainly hopes so, for he was “Raised on Radio” in the days prior to the invasion of the Boob Tube. A warm spot for radio remains from those days, and he is still an avid consumer of broadcast radio.
But nobody will take on this project solely to please a few old men. There is a vitally important and relevant reason to do it, however. And this reason hasn’t changed or diminished one bit over the decades:
“When the chips are down and ‘push’ has arrived at ‘shove’........when the brush and forest fires are roaring, and the tornadoes are spinning, and the floods are rolling across the land.......and when the Wi-Fi “hot spots” turn cold, and the Web isn’t reachable, and all the little belt-clip devices’ screens don’t display anything ......... BROADCAST RADIO WILL STILL GET THROUGH!”
It always has!
It always will!
What do you think?
“Let’s save the universe for RF!”
The Old RF Curmudgeon