The Demise of Real World AM Radio
A Commentary by Ralph E. Evans
Topic: What is the Approximate Cost Associated
with Typical
Distance Education Networks Today?
At the risk of adding to the bedlam regarding the AM NPRM, I would like to voice a couple of observations from my perspective of 40 years in the broadcast business. We at Evans Associates are versed in both the management issues and the engineering issues which are raised whenever a major change is contemplated in the regulatory environment.
There has always been an unfortunate schism which runs through the professional engineering community, dividing the "desk" engineers from the "field" engineers. There are a few broadcast consultants and station engineering departments with feet firmly planted in both camps, but these tend to be the minority. Some of us view the field end of the business as a lesser-skilled vocation, existing primarily to support the designs and implementation strategies which have been predetermined by theory and well-tried practice. This is rather akin to the French view of wine making, whereby the central authority knows everything there is to know about making wine (gathered over 150 years), and dictates to the vintners every detail of growing, blending, and labeling. With this model, there is no room for field verification and experimentation in light of technology improvements. As a result, all the wine innovation is done in other countries, such as California and Australia.
Complicating this schism is another triage which divides the "specifiers" from the "functionalists". The specifiers, which tend to be the theorists, believe that by writing enough regulations and formulas, infrastructure can be built without extensively verifying the performance of the final system. The specifier is therefore removed one step from the creation process. He or she relies on faith that the specifications will not stifle innovation, and that unknown factors will not render the assumptions invalid. Generally, changing the specifications to reflect new innovations and discoveries is impossible or at least difficult. On the other hand, the functionalist believes that the basic mission of industry regulation and professional standards is to reach a verifiable end result, by whatever means and using whatever materials are apropos at the time.
An example will illustrate this point. Many of us who are automobile buffs wondered why American cars continued to have round headlights long after other countries had benefited from the styling and functional superiority of rectangular reflectors. The answer had lain in a trap set by a government specifier, who long ago chiseled into granite the fact that automobile headlights will have a DIAMETER no smaller than five inches. The intent was to specify a particular light output, which could have been done by insisting on a particular lumen profile (requiring field measurements). Since bureaucrats could not figure out what the diameter of a rectangle was, the new lights were not allowed in this country until the massive and unwieldy machinery of specification could be activated to change one word in the Code of Federal Regulations.
Many of us do not "close the loop" by using valuable field data to verify and improve our models. We dismiss nonconforming field and proof data as the product of inexpert or disordered technique. We do not inform our professional organizations or the FCC when real-world data casts doubt upon existing paradigms for fear of "rocking the boat", or "derailing the process". Besides, who would pay for such an effort (remember digital television - why O why did we retain the 6 MHz. channelization for DTV, an artifact of the analog world, when field data showed a marked weakness in this approach).
Obviously, the MTV-generation solution for troublesome field data is to eliminate the field data, or more precisely, eliminate the knowledge of what is happening in the field. Out of sight, out of mind. Nada. Zero. While it is true that complete exclusion of field measurements is not contemplated by the NPRM before us, the trend is clear, and it does not strain credibility to envision a time in the near future when "reduction" becomes "eradication". Eliminating real-world information as a feedback path would, indeed, reduce the incidence of headaches to engineers, managers, and regulators, but it is doubtful whether such changes would maintain the legacy process of steady improvement to our robust, vibrant, and technologically sound broadcast infrastructure. And speaking of zero, I am old enough to remember when the "zero null" advocates of the 50s and 60s were crushed under the weight of massive field data showing zero nulls could not be achieved (even if it was possible, how would you measure it?). Now that really made a lot of heads hurt; the price of progress appears to be a hurt head, just as eternal vigilance is the price of liberty and all that.
When field measurement expertise is a lost art, and field meters are no longer economically manufactured, how are improvements or impairments to be verified (try building an array with 60 degree towers and 50 degree tower spacing and tell me how it works)? We as engineers tend to speak to the arcane matters of interference contours and skywave calculations, while ignoring the broader implications engendered by these shifts in policy. I am speaking to the loss of a stable process which has served us well to date, the absence of which represents a slippery slope to a European broadcast model of shrill, unimaginative archaic old fossils dotting the landscape like so many broken windmills (broadcast stations and/or broadcast engineers - take your pick). Our professional role would then be reduced to jockeying for position in a race where the horse is specified, the pace is regulated, and the result is fixed. But wait - is this not exactly the point? Isn't AM broadcasting dead? Who cares anyway?
I believe we should care, because if AM dies, it will be at least the third time for this particular phoenix bird. It is my opinion that any owner who can't find suitable programming for their AM station today is suffering more from a lack of imagination than from market abuse. Rather than reduce or eliminate the field data, how about if we (AFCCE, FCC, SBA, et al) create a North American Data Bank which actually makes field information available for use by design engineers and paradigm shifters? Why don't we improve the feedback path instead of crippling or breaking it? Why don't we use this data to improve all AM stations so they can keep up with changing technology?
While important, such tangential concerns beg the question. Should we continue with extensive field monitoring of AM facilities or should we not? Field work is expensive and boring, and requires that we get off of our chair and get out of the office. Frequently, it has been known to interfere with poker club and golf. The next time we are filling an inside straight or putting for an eagle, let us be very clear as to what the lack of field verification would mean.
The e-mails and the letters to the editors in this matter with mixed emotions, the most prominent of which is nostalgia for the days when broadcasters really CARED about their real-world service area. One person was occupied with a theoretical justification concerning high angle radiation suppression for a parasitic radiator (used by a cell-phone company) which had been "detuned". Although this question has an answer, such theoretical concerns represent a minor consideration if the performance of the array is not adequately monitored. This particular preoccupation does illustrate my point however, since we have found that very few parasitic radiators are properly detuned. This is especially true of broad-based towers, and - surprise - only field measurements can ferret the truth. The literature clearly documents that two sets of current distribution measurements are required to determine the effectiveness of the detuning apparatus, which requires climbing the tower with an actual non-virtual field meter. It is also current practice to stop the skirt wires well short of any antennas mounted on parasitic towers, justified by some "rule of thumb" the genesis of which has been lost in the dusty engineering tomes of time. I have seen numerous cases where this truncated detuning practice causes the skirt to actually "drive" the short tower section above it, the antithesis of the desired result (while O by the way blowing off the high-angle suppression). Such ineffective detuning is difficult or impossible to diagnose with near-field measurements, because of incremental contributions to the RSS field along the length of the tower. More of these stories are available from the Evans archives ... but I digress.
Of course, without the requirement for periodic monitoring, the associated AM station will never know there is a problem. Even if the FCC places conditions in construction permits for new potentially re-radiating towers, this does not address power lines, illegal towers (I just know there are none of these), buildings, church steeples (I have a really good example from Chicago), water towers and etcetera etcetera.
Before any of us comes down on either or any side of the desk/field/specify/functional schisms, I would submit that he/she review the case history of WNYR (now WDCZ) in Rochester, New York, which operated on a U.S. Clear channel for many decades. Recently, over the course of two years, WNYR documented a steady erosion of its service area due to interference from a co-channel station in Toronto, Ontario. Field research showed that the Toronto station's signal was being reflected from a massive nearby building, which was being gradually built in phases. Ultimately, the 2 mv/m contour from Canada invaded the State of New York, causing a DAYTIME 40 mv/m limit for WNYR. As a first reaction, the Canadian Communications authorities insisted that theory did not allow such interference to exist (Hah - remember the War of 1812, Yankee). Ultimately, armed with extensive field data and the North American Regional Broadcasting Agreement, the problem was recognized and solved with the assistance of the U.S. State Department and the FCC International Branch by moving WNYR to 990 kHz., a Canadian Clear Channel. With the soon-to-be instituted "open ended" reduced verification model, this problem would have had no solution, since the NARBA tends to follow domestic proclivities.
As an old fossil in this business, my stakes are limited, so I have no intention of getting off of my chair and penning an urgent and impassioned response to the FCC's notices.
But a word to you kids out there -- beware ... reality DOES matter, and sometimes it takes a major war to sort things out after perception and prevarication replace verification and responsibility.
"All that is necessary for deskism to succeed is for good field men to do nothing" -- Anon
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