100 years ago this December, voices spoken on one side of the Atlantic shot through the atmosphere and materialised on the other side of the ocean. It was a moment of jubilation for those involved and proof of concept that formalised the possibilities of an emergent zone of signalling and communications called radio. It also helped to bring into focus the unrealised potential of this technology as a mechanism for access to, and transference of, signals of all sorts from around the globe.

These first transatlantic voices were carried on wavelengths of around 200 metres. At that time, which was before the creation of the International Telecommunication Union who coordinate the use of various frequency bandwidths on the radio spectrum, the length of the waves sat at the cusp of two bandwidths: the lowest end of medium wave and the highest end of shortwave. Not only had this amateur broadcast achieved new distances over which communication might pass, but it also demonstrated the process of skywave propagation. This method, whereby radio signals are bounced off the ionosphere (the electrically charged upper layer of Earth’s atmosphere), extends the range of transmission of a radio signal considerably.

What made skywave propagation especially interesting was that, as a technique, it was being actively explored by both amateur radio enthusiasts (the so-called ham radio movement) and commercial interests alike. In fact, throughout the 1920s experimental approaches to radio (broadcast and otherwise) were an area of intense interest and research. This attention was aided by booms in broadcast hardware and a growing understanding about how the technology could be deployed to radically reconfigure the ways in which transmission of voice, music and other signals might be achieved over greater and greater distances.

While energy and money were initially poured into all bandwidths, the commercial interests that came to dominate radio placed a particular emphasis on AM (usually operating as medium frequency) and FM (very high frequency). Between these frequencies, though, sits the high frequency bandwidth that plays host to shortwave radio, with wavelengths from 100–10 metres. While shortwave started out strongly, as the 20th century unfolded its relevancy started to decline. But as it began to fall away from popular listenership, it cultivated an intensely dedicated audience of amateur broadcasters, ham radio operators and other interested parties who recognised its capacities to tap into, and perhaps even help influence, various social, political and cultural phenomena. It offered an availability and access that were as powerful as they were compelling.

Shortwave radio however is not always dependable. It is reliant on a variety of favourable technological, geographic and atmospheric factors. As a result, shortwave transmission and reception require a sense of active engagement and investigation from those occupied with it. Scrolling through the bandwidth day or night will almost always expose unexpected transmissions, bounding through the atmosphere, emanating from a place likely far away. From the earliest times, this volatility has encouraged creative investigations and provoked a sense of deep listening into this dynamic sonic environment, one in which the horizon is not flat but curved and eternally in flux.

For myself, shortwave radio has always been a point of fascination and curiosity, and it’s an interest shared with a great many other musicians and artists across the generations. Whether it be in the context of ambient or concrète compositions, or in improvisational situations, shortwave transmissions offer not just a wonderfully dynamic sense of texture, but they also offer a seductive quality of instability. They are transient, haunting and haunted, never allowing you a sense of attachment or a confidence that the connection will be maintained. They fail, and in doing so, they force you to be attentive and in a state of anticipatory listening.

In 2020, as the first lockdown wound on, I found myself the most engaged in the medium I had been in many years. It’s hard to explain how I arrived there, but I found myself listening and recording daily to a variety of devices, whether they be handheld radios or through online portals such as the excellent facility websdr, run out of the Faculty for Electrical Engineering, Mathematics and Computer Science at the University of Twente in The Netherlands. For my own pleasure, and distraction too perhaps, I recorded, cut into, collaged and layered these intercepted signals using a variety of aleatoric methods, ultimately creating a suite of shortwave etudes (as yet unpublished).

Part of the appeal was an echo of that excitement those first amateur radio explorers felt upon hearing voices from a distant location. As the world shrunk during the early days of the pandemic, the shortwave radio spectrum brought with it a realisation that although our freedom of movement may have been constrained, the ideas and expressions we hold dear were still able to propagate and travel. These waves, and others like them, now carried our messages and they therefore carried us.

Shortwave’s history as a musical tool traces a history back into the heart of the 20th century. Pauline Oliveros singled out her childhood experiences with shortwave (and a crystal radio set) as providing some of her first significant sonic encounters. “My father had a shortwave radio,” She told Red Music Bull Academy in an interview. “I enjoyed the sounds of the shortwave turning as well. Those were sounds that I liked”. This passion for the unfamiliar and unresolved voices resonated too for William S Burroughs, who once called shortwave “the most interesting sounds on the air”. This passionate statement was manifest on a number of his cut-up tape works collected in Break Through In Grey Room.

Like the medium itself, some of the characters who exploited its potentials forged histories that are hazy, perhaps even clandestine. One such pioneer is Vera Wyse Munro, who has only very recently been recognised thanks to the championing of a new generation of radiophonic enthusiasts including the radio-devoted project Sisters Akousmatica. Born in New Zealand, Vera Wyse Munro was an avid radio experimentalist creating works of Morse poetry and other novel performances, which often took place without warning so as to evade any potential conviction for unauthorised broadcasts using unsanctioned radio frequencies.

Around the same time as these artists were experimenting with broadcast, John Cage was beginning his explorations into the ideas of reception, and specifically the alien qualities of radio without a focused source. These explorations became the basis of Imaginary Landscape No 4. While the composition has gone on to become more a celebration of Cage’s preoccupation with chance operation, its earliest presentation which he orchestrated in 1951 resulted in something rather like a minimal noise collage. As the piece was presented late in the evening, many stations had stopped broadcasting, so the sonics presented in those moments reflected more the unsteady tones, hisses and crackles traditionally existing within the shortwave spectrum than the random intercutting of music and voice that the composition has come to be associated with.

Whilst Cage’s engagement with the medium might have been somewhat fleeting (he did expand it in 1966 with Variations VII), and others like Angus MacLise dabbled with shortwave across the 1960s and 70s, some artists have dedicated many years of their creative practices to shortwave. Tod Dockstader is one such example. His Aerial series, which is a reduction of over 90 hours of recordings, captures an unabated obsession with the eerie textures and ghost frequencies that appear and vanish moment to moment. Across three editions published in 2005 by Sub Rosa, Dockstader staked out a significant territory of radio-based composition that expanded outward from his more electronic works of the 20th century. The Aerial pieces are deeply tonal and at times share the same lush timbres of William Basinski’s evocative Shortwavemusic album (recorded in the early 1980s and then finally released in the late 90s) and Stephan Mathieu’s magical Radioland. Others too have utilised shortwave extensively as a dedicated sound source including Michael Snow, Alan Licht, Scanner and John Duncan, who also happens to be responsible for an artist multiple, Black Moon, which includes a custom-made shortwave radio, antenna and Morse key.

The Conet Project, completed by Akin Fernandez, is another exhaustive shortwave study. If there was an example of a documentary style field recording project dedicated to radio then this might qualify as the prime illustration. Originally released in 1997, the five CD set documents numbers stations (stations that broadcast numbers, repeated elements and occasionally break into esoteric phrases and sequences) which emerged during the Cold War and function as code transmission facilities through which international spies could be given instructions by their controlling agencies. The stations have acquired great names over the years including The Buzzer (UVB-76), The Gong Station, and the Lincolnshire Poacher, which stopped broadcasting in 2008.

Today, there is a nascent generation of artists who are primarily focused on the radio spectrum. Amongst the more established of these practitioners is New Zealand artist Sally Ann McIntyre. For almost a decade, she has created live performances and recorded works that expand the approaches to shortwave radio and FM. As Radio Cegeste, she has released atmospheric shortwave recordings that typify her interests in the textures of static, as a kind of unsettled palette from which sonic waves fields coalesce into pools of noise and crackle.

Orbiting these more creatively based considerations of shortwave are other pursuits that celebrate the spectral resonance of radio, including those of the occult and paranormal such as electronic voice phenomena (EVP). Shortwave radio static has been a favourite territory for those seeking to bring forth the voices of the dead through EVP. In essence, EVP asks the receiver to listen into the so-called white noise and fizz of the radio spectrum and from that, seek out voices that lie between the sonic detritus. It traces a linage back into the pre-history of shortwave, and links into the development of the telegraph and other early communication technologies. Artists such as Michael Esposito (often in collaboration with others such as Carl Michael Von Hausswolff and Leif Elggren) has worked extensively with this approach and there are tapes from the 1980s of Genesis Breyer P-Orridge, Peter Christopherson and William S Burroughs also experimenting with EVP.

In many respects, EVP is a form of immaterial anthropology, a reaching out towards that which is not readily understandable, perceptible, or perhaps even not able to be received. This unsteady anthropology of the incorporeal is further developed by characters such as Dr Jennifer Walshe’s invented Irish radio experimentalist Róisín Madigan O’Reilly whose imaginary dreams of static and noise that filled the radio spectrum have recently manifested a series of radio based performances in a variety of contexts.

Like EVP, O’Reilly’s daydreams and imagined narratives have descended from ‘thin air’ and been received as signals; Walshe’s creation somehow finding listeners in other far-off places. It is an example of a practice that acts as an apt metaphor for how many artists choose to engage with shortwave radio more broadly, by allowing it to lead, to suggest and to unfold. All the while being carefully examined with a heightened sense of auditory attentiveness.

Our special Radio Activity feature can be found in The Wire 499. Subscribers can read the feature at our online archive, where you can also find Jah Wobble’s Epiphanies column in praise of shortwave. You can find out more about Room40 and Lawrence English's work at their website.