As has been widely reported in other places, the NAB (National Association of Broadcasters) has completed its study of AM Radio and recommendations to improve the service. The NAB has taken a cautious, if the not somewhat paternalistic approach of holding the report while they review their options. It seems that the technical nature of such a document would not be understood by us mere mortals.
Some of the AM improvement options that have been bantered about in the past include:
Moving AM stations to the vacant frequencies of TV Channels 5 and 6, see this.
Reducing the number of AM stations on the band, see this.
Increasing transmission power of AM stations, see this.
Converting AM stations to all digital modulation, see this.
There may be a few other options considered also.
It does not take too much analytical prowess to deduce where the NAB’s proposal is going. My prediction is that they will be promoting an all-digital “solution” to the AM broadcasting issue using iBquity’s HD Radio product. I base this prediction on the fact that all of the major radio members of the NAB (Clear Channel, Cumulus, CBS, et al) are heavily invested in the iBquity product. For this reason, the NAB will find (or has found) that digital broadcasting in the medium wave band will solve all of the currently perceived problems with AM and everyone should embrace the technology.
A few numbers to note:
iBiquity and the FCC data base reports that there are currently either 270 or 299 AM stations licensed to operate with HD Radio. Other sources note that several of these stations have been turned off and the actual number using HD Radio is 215.
Currently, HD Radio is transmitted 4-6% of the AM stations in the country.
It costs $25,000 US to license a single HD Radio station through iBiquity. They are, however, discounting that to between $11,500 and 13,500 and have a convenient payment plan (limited time offer, expires December 31, 2012, FCC license fees are extra).
It costs between $75,000 and $150,000 to equip and or modify a single AM station with HD Radio gear.
Unless iBiquity drops all patent claims and licensing fees to use its product, an FCC mandate for AM stations to install HD Radio would be skating dangerously close to corporate fascism (AKA Mussolini Fascism or Corporatism) as one corporate entity would then control broadcast radio by licensing its modulation scheme. And no, the patent is not going to expire.
Digital modulation schemes used in the medium wave band have their own set of technical issues. HD Radio is not the panacea for AM broadcasting’s self inflicted woes.
There has been lots of hand wringing and ink spilled regarding the sorry state of affairs in the senior service. AM is plagued with problems; interference, poor bandwidth, etc. To that end, the NAB has launched studies and initiatives and hired all sorts of pricey consultants to consult with. Here is my own AM improvement plan and it is rather simple:
Clean up the transmitter site.
Get rid of AM HD radio.
Variable IF bandwidth receivers.
Improve Programming.
How many of us have seen AM transmitter site dumps? Deferred maintenance, malfunctioning directional arrays, trees growing up on the ground system, flooded buildings and ATU’s, rusty towers, transmitters not a full power, ground system deteriorated or missing all together, just to list a few problems. Many AM transmitter sites are technical disasters. Think that these things have no bearing on the AM station’s signal? Think again.
Differed maintenance, AM transmitter site (there is a tower in there somewhere)
Trees growing around the tower base can attenuate the signal by 30%. A comment from a well known engineering firm:
…Recently XXX field engineers had occasion to measure an AM station at XXXX kHz before and after removing vegetation in the vicinity. The station had a quarter-wave tower. The base area had grown up in brush and hardwood trees to a height of perhaps 30 feet (9m) and this extended from near the base across the entire ground system. After clearing (cutting, no ground system disturbance), the signal measured at some 16 locations on four radials went up a uniform amount of about 15% or 1.2 DB. That’s about a 30% increase in radiated power…
That is an inexpensive power boost and they didn’t even have to file with the FCC! A 1 – 2 dB power gain is pretty nice and can mean the difference between a listenable signal and static. How many times have I heard the lament that AM band is full of noise and not listenable. Certainly, there are major challenges in the urban listening environment. Putting forth a better signal will overcome some of this electrical noise.
There is a reason why engineering standards were developed for the physical plant; they work.
There is no cure for the noise that AM HD Radio puts out into the adjacent channels. This self interference benefits none, not even the station transmitting AM HD Radio. This dubious technology has proved itself a non-starter and should be discontinued. For smaller station owners, the cost of implementing AM HD Radio is prohibitive. Licensing of a proprietary modulation scheme, new transmitting equipment, specialized exciters plus any needed bandwidth improvements to AM antenna arrays can easily exceed $100,000.00. Unfortunately, it is often the small AM radio operators that are making a good showing, and serving their community of license and making money. These are the very stations that are hurt the most by adjacent channel AM HD Radio interference.
Receiver design over the last twenty to thirty years has been the greater issue with perceived low AM broadcast quality. AM receivers have an average bandwidth of just 3-4 KHz, which is slightly better than telephone quality. AM broadcasting has gotten a bad wrap because of this and there are many comments about how AM is “inferior quality” to FM. With a quality older receiver, AM can sound very good. Of course, the receiver manufactures all point adjacent channel interference as their rational for reducing IF bandwidth. Why not leave it in the hands of the user? The GE Superradio had this feature with a “wide” and “narrow” setting for AM reception. They worked remarkably well. A receiver could also be designed to automatically increase IF bandwidth at higher received signal strengths.
Finally, as the saying goes; Garbage in, Garbage out (GIGO). This holds true for many things including radio programming. Expecting that mediocre satellite syndicated news talk will garner great ratings and huge revenues is silly. For years and years, station owners have put minimal effort into AM radio and expected big returns. It is not working. AM stations that go against that trend; those with unique formats (Gasp! Music, on AM?), local content, and community oriented programming can and do succeed. They are fighting an up hill battle in both directions. With all of the business pressures from larger broadcast groups, interference issues and negative viewpoint on the viability of the AM band, one wonders how long they can last.
Because Hey! It’s digital, therefore it must be better!
I found this faulted HD Radio exciter on my weekly site visit for WFAS-FM. I have no idea how long it was in the fault condition. The radio station received zero calls about the HD Radio being off. When I looked at the fault log, it stated that it was unable to ping something or another. However, the reason for the exciter shutting down was… wait for it… the fault log was full.
I rebooted the unit, it came up without problems and there appears to be no lingering communications issues.
At least these things weren’t terribly expensive… Oh no, wait, they were.
Well, at least people are getting enjoyment from their wonderful sounding digital radio, except, no: People don’t seem to know about it, or care.
So, the radio stations must be making tons of money on this thing, right? What? No?
Perhaps it is a good time to pose a few questions regarding the future of radio broadcasting and digital radio in particular. For this article, I will assume that everyone understands that digital radio is a type of modulation using data transmitted at high speeds, which is reassembled in the receiver to generate audio for the listener.
Why is digital radio needed?
What are the benefits of transitioning to digital radio?
Who would benefit most?
Who would benefit the least?
What are the alternatives to digital radio?
Why or why not proceed with the transition already started?
To answer the first question, we need to understand the current consumer marketplace and the all-pervasive notion of disruptive (aka destructive) innovation. That is to say, a new technology that builds on existing technology or knowledge, while eventually replacing or destroying its predecessor. Think; horse and buggy vs. automobile, microwave network vs. fiber optic network, wired telephone network vs. cellular phones or film photography vs digital photography. In other words, the older technology becomes obsolete and is abandoned in view of the improvements brought on by innovations.
Disruptive Technology
No one can argue that innovations have not greatly improved our lifestyle and productivity in the last one hundred years. Few would opt to permanently return to an era of no electricity, no electronic communications, and no cars. In order for the destructive innovation argument to succeed, however, the technology in question must be improved in a way that benefits the greater society.
Digital modulation methods have been under development since ATT started using T-carriers to transmit telephone calls over long-distance circuits. Over the years, several different methods were developed including Phase (or Frequency) Shift Keying (PSK), Multiple Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), and Orthogonal Frequency Division Multiplexing (ODFM).
For various purposes, these digital modulation methods offer distinct advantages over analog modulation methods.
Thus, the proponents of digital radio broadcasting postulate the advantages of transitioning to digital radio are:
Improved sound quality, often using terms like “CD Quality,” etc
Improved spectrum efficiency, more broadcasting channels for the same amount of frequency allotted.
Improved coverage area, less interference, out-of-band noise, etc
Value-added accessories, such as data services (song title and artist), album art, Electronic Programming Guide, H. 264 video, etc
Keep up with evolving technology
Thus, the question of why digital radio is needed is answered by listing the possible benefits of such a transition. By the list of benefits above, most consumers would find improvements in digital radio broadcasting as would most broadcasters. In theory, it is not a bad idea.
In the real world, theory, and application are often radically different. Innovation is most often, although not always, driven by a profit motive. Digital radio technology is no different. The proponents of digital radio are attempting to move technology forward while making a profit. There is nothing wrong with that, provided the consumer sees the value in the new technology and embraces it. That is a key part of the current digital radio puzzle which is missing; the consumer.
Unfortunately for digital radio broadcasting, several of the above benefits have not been fully realized in the first iteration of the technology. In several countries, digital radio has taken the form of IBOC via either DRM or HD Radio®. Others choose to do DAB via Eureka 147. In almost every case, the average consumer has not embraced the new technology for several reasons:
Coincidentally with the rollout of IBOC, the mobile internet has become pervasive through the use of things like smartphones, tablets, and similar devices. Via 3G and 4G mobile networks, consumers can access almost an unlimited number of programming choices from across the world.
Programming offerings on digital radio differ only slightly from those available on analog radio. Consumers are left with no compelling reason to purchase or install a digital radio.
The technical advantages of digital radio are not consistent enough or significant enough to make a difference in the listening experience.
The availability of other competing entertainment mediums such as MP3 players, satellite radio (XM/Sirius), internet streaming, etc.
Many point out that internet-type services require an internet service provider (ISP), mobile data plans, or some other type of paid service. Further; 3G, 4G, and or WiFi services are not universally available. All of that may be true, however, mobile data networks are rolling out far faster than IBOC. Consumers appear to be willing to pay for internet service for a variety of reasons, including mobile listening.
The major flaw of internet technology is the capability of ISPs to cut off service at the request of the government for any reason. There is also the ability to block access to certain websites, countries, search results, or services. There are several bills currently under consideration in Congress to codify this, which is an ominous development. Eventually, one of these bills will make it through and become law, creating some form of censorship on the internet. In light of the potential issues with the internet, free, over-the-air broadcasting is necessary, if not vital, to democracy provided the ownership is dispersed and diverse.
There are distinct advantages to digital radio broadcasting which may be realized with different systems that are developed in the future. It may require a re-think of what it means to be a broadcaster and how to make digital radio broadcasting more like IP-based interactive web streaming, available for free using different frequencies than what is in use currently. The general public has shown, by their lack of interest, that digital radio broadcasting as is being carried out today is not necessary. While digital modulation has been around for quite some time, the politics and bureaucracy involved with creating a digital radio broadcasting service has stunted development, making the technology almost irrelevant.
