Welcome to Free World Blues. In this recording, I’ll be investigating incidents of “meowing” and other animal-noise broadcasts on the International Aeronautical Distress Frequency, and using open-source data to track down the meowlefactors.
I. The Meowings:
First, a bit of background on what’s happening: Back in 1886 – that is, 140 years ago as of the date of this recording – Heinrich Rudolf Hertz demonstrated the use of radio waves for communication at a distance. It quickly became clear that emergency communications were an excellent use case for this then-new technology. The first emergency transponders were morse code beacons carried by ships and hot air ballons starting in 1901; there were no transponders aboard “aircraft” in the modern sense at the time, because heavier-than-air flying machines were yet to be invented. However, after the Wright Brother’s first flight in 1903, these beacons were quickly adapted to powered, heavier-than-air craft. This is one of many examples of how aviation takes after seafaring: both ships and aircraft have “pilots” who control lateral motion with “rudders”; ships transit between “ports” while aircraft use “airports”; etc. From the standpoint of emergency preparadness and response, there are also similarities: both seacraft and aircraft have a tendency to become lost while operating far from Civilization; both maritime navigation and flight can be endangered by poor weather, and especially by poor visibility; both types of vehicles can find themselves in emergencies due to fuel exhaustion; and airplane-airplane collisions and ship-ship collisions are a major cause of fatalaties in both cases. One could even say that “running aground” is the nautical equivalent of “controlled flight into terrain” (indeed, the Titanic was sunk by “controlled sailing into an iceberg”). The fact that aircraft and ships are both closed environments also means that they are subject to hijacking, and that onboard fires pose extreme hazards. Since both types of vehicles are typically quite valuable, both in a financial and strategic sense, they are of great interest to military planners, and significant loss of life has occured when civilian aircraft and seacraft have been attacked, either accidentally or intentionally; compare the 1917 sinking of RMS Lusitania with the 2014 shootdown of Malaysia Airlines Flight 17.
One legacy of this complex relationship between maritime and air operations is that aircraft have “inherited” the nautical practice of using certain radio frequencies for emergency communication. I won’t be discussing every emergency frequency used by every aircraft and seacraft in every country over the century-and-a-half during which this practice has been commonplace, but the frequency 121.5 Megahertz, in the VHF band, or Very High Frequency band, is currently the international standard as a “least common denominator” for both airborne and seaborne distress calls. Some might even say that 121.5 is the “Intenational…AERO-NAUTICAL…distress frequency”, and I’m among the some whom’st would say that, because its true. Numerous other emergency frequencies are used, including harmonics of 121.5 MHz (such as 243 MHz), and there is an effort to separate nautical from maritime emergency frequencies, as well as to develop specific frequencies for military distress calls and for locator beacons. Radio technology has greatly evolved over the past 140 years, and there is no such thing as a “perfect” emergency frequency: lower frequencies tend to have longer range, reflect better off terrain and the ionosphere, and are attenuated less by conductive materials – this last point is an important consideration for sending distress calls through water (such as from a submarine) or through snow (such as from a rescue beacon carried by an unlucky heliskier who has been buried under an avalanche). Shorter frequencies provide better audio quality (and can transmit data at higher bandwidth generally), can be broadcast and recieved with smaller antennæ, and can be located more precisely. Combine these considerations with the need to account for existing radio technology (and upgrade costs), current spectrum use, interference from man-made and natural sources, and the need to coordinate among 195 countries, and you can see why the situation is complicated. That said, I will mainly focus on 121.5 MHz in this recording. Note that, in aeronautical contexts, this frequency is often read as “one-twenty-one-DECIMAL-five”. In the United States, pilots typically refer to this frequency as “guard”, for two reasons: First, it is reserved, or “guarded”, for emergency use, i.e., it other uses are prohibited. Second, under most circumstances, pilots of commercial aircraft are legally required to keep at least one radio tuned to 121.5 unless there is a compelling reason to do otherwise. Of course, if an electrical fault develops in a pilot’s radio and smoke starts pouring out of it, he is perfectly justified in pulling the associated circuit breaker, but aside from these rare situations, failure to listen on 121.5 isn’t merely a mistake – it’s a crime. Thus, it’s customary to keep a radio tuned to 121.5 and “guard” the frequency settings – “don’t touch that dial”, one could say. If you are using Russian or Soviet radio equiptment, be aware that, because the Russian words for million (миллон) and billion (миллард) both start with the same letter, Russian will sometimes repeat the letter “к” (their abbreviation for кило, or “thousand”) in order to indicate multiples of one thousand. This usage denotes implied multiplication. For example, just as “a = xy” implies “A equals X times Y”, a Russian might write: