July 23, 2024

Prime Electrolite

Transforming Health

The Health and Future of AM Broadcasting?

This one is emotional, of course. After all, AM radio is one of the very oldest uses of the radio spectrum (beginning ~1919), as evidenced in part by the Medium Frequency band on which it began and still operates. There isn’t much other remaining on-air activity that predates it on the spectrum, perhaps just the Maritime Service, a few Public Coastal stations (overseas telegrams), and the Amateurs. AM broadcasting is one of Mother Spectrum’s first children, and it will be sad to see it go.

But it should go. It’s been operating essentially unchanged through a turbulent period in the advance of technology and telecommunications, and it just doesn’t fit well any longer. As a medium it can’t compete effectively, its audience is growing smaller, the economics are poor, and in the long run it’s probably best just to close it down, with appreciation and admiration, and to move forward. The Curmudgeon will try to make that case.

By FCC mandate, for decades now the U.S. has been supplied with dual band AM-FM consumer radios. Everyone in the US has access to the broadcast FM band; everyone appreciates the inherent quality advantage that FM (stereo) possesses. AM’s declining market share and limited variety of programming amply indicate that fact.

There was once a time when broadcast AM radio signals reached far across the sparsely-populated countryside, bringing news and entertainment to isolated rural communities. The existence of a dozen or so “clear channel” nighttime AM station assignments in those days ensured that everyplace in America could be “connected” to the major population centers in a way never before possible.

But not anymore. The clear channel AM station assignments have long since passed into history. Just about every burgh now has its own FM station, or can receive service from a nearby city. Satellite radio can rain signals down onto almost every location in the continental US, bringing more programming and diversity on one carrier than exists on the entire AM broadcast band. The Internet can provide world-wide radio programming in dizzying abundance.

So what is the current state of AM? Let’s look at the engineering side first. There have been no major improvements in the basic transmission system for perhaps seventy-five years. Its old technical limitations still remain: restricted audio frequency bandwidth, no inherent noise immunity for reception, and an engineering nightmare in spectrum management because of the nighttime ionospheric propagation. The VHF broadcast FM band has none of these.

And there’s not much hope for future AM improvement either. Well, there is AM HD transmission (i.e., IBOC). True, it does help close some of the performance gap with FM. But IBOC, as it is currently practiced, really requires 20 kHz (occupied bandwidth) channels; just look at a spectrum analyzer to see for yourself. So, if you want to “rescue” the AM band with IBOC, then plan to re-engineer the entire band on a 20 kHz channel raster.

From an economic viewpoint, AM cannot compete with FM in musical programming, which comprises the majority of the radio broadcast arena. All AM programming now provides (typically) is news/sports/talk. And all of these formats certainly would fit into FM just as well. There really is nothing in AM programming that is unique any longer. Amos and Andy, along with the great networks, are now long gone.

It’s come to this: we just don’t need AM broadcasting any longer! We can move forward quite well with terrestrial FM/satellite/Internet radio. So, with many a tear bouncing off his desktop, the Curmudgeon says: Let’s just “sunset” it! Let’s pick a date, perhaps fifteen to twenty years in the future, on which, with great nostalgia and fanfare, we will just turn it off. The same way we should handle the future cessation of terrestrial television broadcasting.

And many of the same planning points will apply to the sunseting of AM radio as apply to terrestrial television. The present broadcasters should receive accelerated depreciation tax credits for their transmission plants and the value of their licenses. They also can expect handsome windfalls from the eventual sale of their transmitter sites, around which communities have grown. These are now very valuable parcels of land!

But what about continuance of their programming, post sunseting? Aha, technology to the rescue! Their programming, the news/sports/talk channels, will fit quite nicely on the HD-2, HD-3 channels, etc., of city-of-license VHF-FM stations. In fact, at least one major metropolitan all-news AM station has already begun simulcasting its entire main program stream on the HD-2 channel of a company-owned FM station in the same city. Indeed, everything worth saving can be fit into FM HD.

Finally, once we will have “liberated” over one Megahertz of Medium Frequency spectrum, what in the world can we then do with it? That question took some thinking on the part of the Old Curmudgeon, but at least one clear answer did finally emerge.

With the wide land coverage area inherent in MF transmission, the “AM Megahertz” would be ideal for a broadband regional data distribution service for the Public Safety community! What a wonderful asset it might become: the ability to push maps, photographs, drawings, and text messages out simultaneously to first responders everywhere, engaged in major disasters and emergencies! And to do so in a way that no VHF/UHF/microwave system could do. That alone is worth “the price of admission.” Re-using the band for this purpose is almost “poetic:” after all, Public Safety one-way voice dispatch began, in the 1930s and 1940s, with the use of AM transmitters on channels just above the top end of the conventional AM broadcast band!

So let’s bid a sad farewell to AM broadcasting, with all the echoes of its past greatness. We love you, we’ll remember you, but we’re moving forward now.