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Sonic Continuum
EUMETSAT images of A-68A from December 2020 – February 2021. Courtesy of John Tellick via EUMETCast.


A-68A calved from the Larsen C ice shelf in Antarctica in 2017. A chunk of ice more than twice the size of Luxembourg, the iceberg drifted slowly through the Weddell Sea before emerging into the open ocean of the South Atlantic. By late November 2020, satellite images suggested A-68A was on a collision course with the island of South Georgia. Mirroring the island in both shape and size, the iceberg threatened to ground in the waters off the coast, forming a colossal obstacle to the migration of penguins and other sea life.

Over the months of November and December 2020, I watched A-68A approach South Georgia through daily satellite image captures circulated by the Group for Earth Observation (GEO), a network of radio amateurs and Earth data enthusiasts using DIY satellite reception equipment to gather information from space. Whether by tapping into the European Union’s ‘EUMETCast’ transmissions using backyard parabolic dish antennas, or decoding the broadcasts of US owned geostationary satellites using a mix of hardware and software, these Earth-watchers meticulously tracked a large chunk of Antarctic ice through a vast ocean. Though located primarily in North America and Europe, GEO members ‘saw’ the iceberg on the opposite side of the planet through radio signals transmitted by satellites. ‘It’s great we still can see through the thin clouds which are nearly always present’ one GEO member wrote. Another added: ‘Some nice herringbone clouds on today’s image’.

In GEO’s forum posts and email threads, A-68A became something held in common, a shared ‘matter of concern’.[1] Perhaps A-68A also presented a necessary diversion during an unfolding series of medical, economic, ecological, and social crises. At the same time, the sharing of information within the group – information gained through the use of specialist radio technology – reflected particular kinds of access, asymmetries in time and leisure, and far-from-neutral epistemologies.

EUMETSAT image of A-68A on January 23, 2021. Courtesy of John Tellick via EUMETCast.

The images of A-68A manifested something else too: an indisputable, visual regime in remote sensing. Images – rather than other embodiments or features of the iceberg – were the currency of information in GEO. Yet, the history of remote sensing is also a history of sounding.[2] It is a history in which sound, born on the electromagnetic continuum of the radio spectrum, became a carrier of data, voice, lyric, and time as part of the expansive forms of signalling and communication that envelop our planet. These radio-borne sounds hold important clues for the ethics and politics of remote sensing practices. They also trouble the visual optics of remote sensing, enlarging other experiments in planetary observation. Using DIY and amateur technologies for listening to radio-borne sounds, this essay explores a sonic politics of remote sensing and suggests what a more equitable electromagnetic commons might sound like.[3]


Early one morning in January 2021, I tune to 5505 Khz using a mini-whip antenna at the University of Twente, Netherlands. I am listening to what this antenna is receiving using a web-based interface called WebSDR.[4] As I do so, an American woman’s voice punctuates the airwaves. Though strangely lyrical, it is unmistakably the voice of a machine. The robotic vocalisation, transmitted from a station at Shannon International Airport, Ireland, broadcasts weather information to pilots flying over the North Atlantic. This is the voice of ‘VOLMET’, a worldwide network of radio stations used for communicating meteorological information to aircrafts.[5]  Established in 1936 to communicate with flying boats between the UK and Newfoundland, Canada, VOLMET is integral to the distribution of weather-knowledge to aero-mobile bodies.

Listen: 5505 kHz – Shannon VOLMET

This is Shannon VOLMET, Shannon VOLMET. Santa Maria SIGNET number 3, XX 2 1 2 2 0 Zulu. Santa Maria SIGNET SIR embedded thunderstorms forecast X to 8 00 North 037 00 West 3130 North 040 00 West 3730 North 040 00 West 36 30 North 03630 West 33 30 North 034 00 West to 8 00 North 037 00 West XX light level Rain Niner 0 Northern west Northwest to 5 knots No 2. Forecast Copenhagen Kastrup Forecast Copenhagen Kastrup…

VOLMET transmissions occur in the ‘shortwave’ zone of the radio spectrum, spanning frequencies between 3 and 30 Mhz. The radio waves in this specific zone have the unique capacity to travel long distances due to their ability to bounce off the layer of charged ions in the atmosphere known as the ionosphere. Rather than traveling in straight lines, these frequencies ‘skip’ and ‘propagate’ from ground to sky and back again. Any information encoded in shortwave frequencies reaches across continents and oceans in a continuum of skywave signalling.

Thinking with sound invites us to move past the content of VOLMET transmissions to investigate the qualities of the VOLMET voice. The voice of VOLMET is generated by text-to-speech synthesis, with each VOLMET station sounding slightly different.[6] VOLMET’s vocal expression has changed over time. For much of the twentieth century, the voice of VOLMET was coded male. Indeed, most text-to-speech synthesis at the time featured male voices, thought to convey ‘competence’ over ‘likeability’.[7] In 1990, the late Ann Syrdal, working at AT&T Bell Laboratories, created a female voice for text-to-speech synthesis.[8] In doing so, she laid the groundwork for the many voices of VOLMET, as well as the celebrity voices of Alexa and Siri.[9]

As Anja Kanngieser has explored, there is a politics to synthetic voices: their pitch, intonation, accent, and frequency register along axes of class, race, gender, education, and sexuality.[10] Indeed, an entire thread in an online forum for pilots centres on the question ‘Who is Mrs Volmet?’ with questions like ‘What does she look like, then and now?’.[11] Several comments agree that the voice of VOLMET is surely better than the real thing “On meeting her, you could see why they kept her in the ‘tower’”.[12] As I tune the dial away from 5505 kHz I am struck by an image of Cassandra, the Trojan priestess forever cursed to utter prophecies, whatever the consequence and no matter who is listening.

Listen: 1933 kHz – The Rusty Toolbox

I mean I found you know that very thin saw! Well, I never put it where it was! I never would have done! Oh no no no. She put it in the toolbox. Which, the toolbox goes outside in one of the green bins. But I wouldn’t put that out there because obviously you know it can go rusty!

The question ‘Who is Mrs VOLMET?’ should be understood in the wider context of radio-borne voices, especially on shortwave frequencies. Listening to amateur radio⁠ – specific frequencies or ‘bands’ in the shortwave spectrum where licensed amateurs can experiment and communicate ⁠– reveals a vast overrepresentation of male-presenting voices. As Anne Gessler has written, this is no accident: throughout the twentieth century, ‘government, commercial and cultural pressure on amateur radio to justify its existence forced the predominantly male hobby to police its borders against female incursions’.[13] Today, female-presenting voices on shortwave amateur bands are so rare that they often cause a ‘pile-up’: a phenomenon during which multiple amateurs attempt to make a ‘QSO’ or contact with a single female-sounding voice.

Late one night in 2019, from a backyard in Brixton, London, I listen to the 160-metre amateur radio band using a portable Super MP1C antenna and some free software called SDR#. I am a newly licensed radio amateur: my callsign is M6IOR or ‘Mike Six India Oscar Romeo’. The 160-metre-band, also known informally as the ‘Gentleman’s band’ among hobbyists, is the oldest amateur radio band and was the staple of reliable communication in the earliest days of radio. As I listen to two radio amateurs discussing a rusty tool box, I feel like I am eavesdropping on a conversation in a pub. This is not the rapid-fire exchange of callsigns and signal strengths I had expected from amateur radio: it is a deeply gendered scolding of a woman who had misplaced some tools (presumably belonging to her husband). As I listen, astounded, I think about how far this conversation is travelling on a frequency where the length of one wave is 160 metres. Did it circle the Earth? How many times?


In November 2020, a new sound work called Receive-Transmit-Receive composed of shortwave frequencies and amateur radio selections, was aired in the Radiophrenia Sound Arts Festival. The sound work, created by a group of women and non-binary persons known as the Shortwave Collective, featured shipping forecasts, long-wave AM radio, radio beacons, VOLMET weather reports, number stations, and the staccato sounds of morse code. They listened to specific shortwave frequencies and documented their characteristics, then pieced the fragments together in the mode of ‘exquisite corpse’.  Audible refrains of radio-borne sound including amateur radio conversations, international broadcasts, medium wave AM, and the sounds of different kinds of data.

Listen: Various Shortwave Frequencies, Shortwave Collective: Receive Transmit Receive

A sonic archive of the radio-borne sounds that propagate around the Earth, Receive-Transmit-Receive illustrates once again the uneven representation of bodies and actors in shortwave radio. In the work, radio amateurs from the UK to Brazil jokingly compare signal strengths. Transmissions of the BBC and classic rock songs echo through static. Yet, by treating these radio-borne sounds as materials to be mixed, hacked, distorted, and enmeshed, and by making space for the emergence of refrains, the Shortwave Collective brings focus to the politics of shortwave radio frequencies. This is a politics of enclosure, in which particular bands are reserved for certain kinds of activities and users. It is a politics of the vestigial remains of the early days of radio communication, during which powerful organisations staked claims to ‘useful’ frequencies. While radio has long been heralded for its community-building capacities and wide listener base, shortwave radio frequencies belie a politics of access, where those with privileged training and elite social positions can transmit, explore, and intervene in the electromagnetic landscape.

Listen: 14.073 MHz – Adriana Knouf, Exomio Fragmissions

What might an alternative electromagnetic commons sound like? For Adriana Knouf, a xenologist, artist-scientist, writer, designer, and engineer, the question of what sorts of signals envelop the Earth via the frequencies of shortwave radio is not only a scientific or physical question relating to the ways in which radio waves may or may not impact human bodies; it is also a deeply philosophical and aesthetic one.[14] As Knouf discusses, it is both troubling and alarming that the electromagnetic and sonic continuum of the radio spectrum is so often employed for exclusionary, misogynist, and racist purposes in well documented ways.[15]

In an artwork titled Exomio Fragmissions, commissioned for Shu Lea Cheang’s Lab Kill Lab programme, Knouf ‘coated the globe radiophonically with transgender genetic variants’.[16] From an apartment in Ljubljana, Slovenia, the artist assembled a portable multiband antenna and linked this antenna to a USB interface, which allowed the use of a software called WSJT-X to transmit fragments of genetic code into the shortwave radio spectrum on the 20-metre amateur radio band. To transmit and translate the code, Knouf used FT8, one of several modes that enable the transmission of digital information in short intervals or sonic bursts of only fifteen seconds. In this way, the 14 Mhz frequency became a carrier for the genetic signatures of trans bodies. Passing through atmospheric layers, landscapes, and cities along the way, the code ‘infected’ an unknown number of bodies, assemblages, and entities.[17] Born on the continuum of the radio spectrum it might have circled the earth before diffracting into land, sea or air.


In West London
I feel the metal staircase beneath my feet,
cold and textured.
Being barefoot enhances the satellite image,
changing the gain of my turnstile antenna,
altering its frequency response.

I have set up a satellite ground station in my flat.
Its component parts are a laptop, free software (prone to glitching),
and a turnstile antenna that I assemble before each satellite pass.[18]

If the making of Receive-Transmit-Receive and Exomio Fragmissions involved remotely sensing and transmitting ‘skywave’ signals in order to intervene in the politics of shortwave radio, another set of experiments more closely reflects the work of GEO by engaging the radio-borne sounds transmitted by satellites. National Oceanic and Atmospheric Administration (NOAA) satellites transmit data through sound that is encoded into a 137 Mhz carrier wave. The sound contains information derived from six primary sensors on the satellite, and it has a characteristic ‘tick-tock’ quality over a high-pitched ringing tone. In order to ‘see what the satellite sees’, one must first extract this rhythmic sound from its radio-borne transmission.

Listen: 137 MHz – Listening Space, NOAA-15 24082020

The project Listening Space by Afroditi Psarra and Audrey Briot investigates ‘the ecologies of transmission that comprise the Radio Spectrum, [and] are no doubt the ultimate expression of the Anthropocene, as they permit the operation of human life as we know it […] and shape our understanding of the planet’.[19] Over three days, Psarra and Briot observed and recorded five NOAA satellite passes and decoded the satellites’ sounds into images. The images, which feature ghostly patterns of clouds and land masses, were then knitted into a series of textile artworks called ‘Satellite Ikats’. In the movement from radio wave to sound to image to textile, information is decoded and re-encoded multiple times. The artists describe how the ‘Satellite Ikats’ ‘encapsulate the information of the system in which they are created – the SDR radio, the error-prone nature of the handmade antennas we used, and the encoded information of the NOAA transmissions of Earth from space’.[20] In this process the goal is not to isolate a satellite image from the technical system in which it is produced, but rather to record the operations of the system in a form of ‘textile memory’.[21] For these artists, then, remote sensing is about listening to a technical system and recording its memories in loops of sound and yarn.

Listen: 137 Mhz – Open Work, Second Body

We: the antenna I hold,
my body,
and the staircase beneath my feet
re-distribute energy,
produce interference patterns,
create new images.

We are more than a set of “global connections”.
Tuned to 137 MHz we are a more-than-human antenna,
a radiant body.
The satellite image:
a “work in movement” (Eco, 12).[18]

To engage in remote sensing is to participate in the (re)distribution of enormous amounts of power. Can different modes of listening trouble the ‘view from nowhere’? In open-weather a project led by myself and researcher-activist Sophie Dyer, the radio-borne sounds of NOAA satellites become a raw material through which to probe the porous boundaries between bodies, atmospheres, and weather systems using amateur radio, open data, and intersectional feminist principles.[22] For the global sound arts festival ‘Reveil 2020’, Sophie and I streamed ourselves decoding the same NOAA-18 satellite transmission from our balconies in Northwest and Southeast London. In the midst of the UK’s first COVID-19 lockdown, we used the constraints of our apartments and our radio environments to explore the relations between our bodies and trans-scalar weather systems, where ‘weather’ might include the meteorological dimensions of the atmosphere as well as the sociopolitical pressures that condition life.[23] We experimented with our bodies as antennas, standing barefoot to access the widest possible electromagnetic field. The resulting image and sonic performance was an ‘open work’ composed of holes, gaps, noise, and interference; as such, it critiqued both the disembodied gaze of the satellite and the visual aesthetics of remote sensing.

Planetary Radio

Like many other media and mediatic infrastructures, radio is not neutral. It is a carrier, a commons, a host for different exclusionary and asymmetrical practices. This politics of access and exclusion meets the politics of the planetary when we consider how far, and on which frequencies, radio waves travel. A significant portion of these radio waves circle the planet, bouncing between the ground and the sky. To tune to these long-distance signals is to consider how they touch landscapes, bodies, architectures, and atmospheres. It is to listen to radio-borne sounds that have travelled vast distances from their places of origin: from the resonant bodies that vibrated air particles near microphones, or the computers that translated code into sonic scales.

What do such radio-borne sounds offer for the politics of remote sensing and Earth observation? Perhaps they provide radiophonic lures for planetary ethics: a series of invitations to rework and rethink how a narrow set of voices and broadcasts are amplified by electromagnetic waves at the scale of the planet. Gayatri Spivak writes of the ‘imperative to re-imagine the planet’ where ‘planetary imaginings locate the imperative in a galactic and para-galactic alterity’ and ‘cannot be reasoned into […] self-interest’.[24] The sense of alterity we encounter at the level of the planet, Spivak writes, ‘is mysterious and discontinuous – an experience of the impossible’.[25]

For Spivak and others, planetary alterity, or ‘planetarity’ is thus an invitation to reach beyond ideas of the ‘globe’ and the ‘global’ that have positioned humans as powerful agents on an earthly stage.[26] Listening to the uncanny radio-borne sounds of VOLMET or the tick-tock tone of a weather satellite does not necessarily lead to a romantic notion of the ‘global village’ or an affirmation of the Apollonian eye. Rather, listening to the sonic signatures of planetary radio enlarges a politics of difference while simultaneously invoking a collective responsibility. Taking up the invitation of the artists cited in this essay: if planetary radio could sound otherwise, could we be otherwise?