S3 Ep4: Making the Invisible Visible

MORE ON THE STORIES

Act 1

Andrew Mitchell 

In Act 1, hear Molly Rasbash's conversation with Andrew Mitchell.

Andrew Mitchell is a Research Fellow in urban soundscape modelling at University College London (UCL). His research interests include soundscape analysis and visualisation, machine learning, and human perception of complex sounds. Andrew has been awarded two PhD and one Post-doctoral Enrichment Awards from The Alan Turing Institute and spent a month in early 2022 as a visiting research fellow at Stockholm University. His ongoing projects include the Soundscape Indices (SSID) Horizon 2020 project, Soundscapy, Deep Learning Techniques for noise Annoyance detection (DeLTA), AI for Urban Soundscape Enhancement (AI USE), the Catalogue of Soundscape Interventions (CSI), and the Soundscape Attributes Translation Project (SATP). 

Andrew is also the host of The Rest is Just Noise, a monthly podcast exploring the relationship between sound and our cities. Each episode, Andrew and his co-hosts and colleagues Dr Francesco Aletta and Dr Tin Oberman speak with researchers and experts from a wide range of backgrounds about their work in urban sounds and sound perception. 

Act 2

Ilan Kelman

In Act 2, Maria Bunyun speaks with Prof Ilan Kelman about Antarticness.

Ilan Kelman is a Professor of Disasters and Health at University College London, England and a Professor II at the University of Agder, Kristiansand, Norway. His overall research interest is linking disasters and health, integrating climate change into both. Three main areas are: (i) disaster diplomacy and health diplomacy http://www.disasterdiplomacy.org ; (ii) island sustainability involving safe and healthy communities in isolated locations http://www.islandvulnerability.org ; and (iii) risk education for health and disasters http://www.riskred.org 

You can find Ilan at http://www.ilankelman.org and Twitter/Instagram @ILANKELMAN

Antarticness can also be found on the UCL Press website.

Act 3

Dr Matthew Ritchie

In Act 3, hear Taqwa Sadiq's conversation with Dr Matthew Ritchie about Radio Frequencies.

Dr Matthew Ritchie received an MSci degree in physics from The University of Nottingham, in 2008. Following this, he completed an Eng.D degree at University College London (UCL), in association with Thales U.K., in 2013. He continued at UCL as a postdoctoral research associate focusing on machine learning applied to multi-static radar for micro-Doppler classification. 

In 2017 Dr Ritchie took a Senior Radar Scientist position at the Defence Science and Technology Laboratories (Dstl) which also involved working as the Team Leader for the Radar Sensing group in the Cyber and Information Systems Division. During his time at Dstl he worked on a broad range of cutting-edge RF sensing challenges collaborating with both industry and academia. 

As of 2018 he has now taken a lectureship role at UCL within the Radar Sensing group. Currently, he serves as the Chair of the IEEE Aerospace and System Society (AESS) for the United Kingdom & Ireland, is a Subject Editor-in-Chief for the IET Electronics Letters journal and a Senior Member of the IEEE. He was awarded the 2017 IET RSN best paper award as well as the Bob Hill Award at the 2015 IEEE International Radar Conference 

 

TRANSCRIPT

Cerys Bradley  
Hello and welcome to series three of med at UCL, the podcast. My name is Cerys Bradley and I'm here to share with you UCL's groundbreaking research and its impact on the world. Each month for me that UCL team and I will be exploring a research theme and gathering stories from all over the UCL community to try and understand it. In our fourth episode of this series, we are making the invisible visible, corny, I realise, but there are so much about this world that we don't see so much that if we looked at it just a little differently, brings new discoveries and unexpected conclusions. In each of this month stories. The researchers we interviewed have taken something we all think we understand and said, Well, what if we think about it like this instead, and the results have been astounding, groundbreaking and beautiful. As I record this now I'm in Edinburgh for the Fringe Festival, and performing a stand up show every day to a wide variety of audiences. And it's very easy to get lost in the process. Hyper fixated on the reviews and the ticket sales and making made at UCL is helping to keep me grounded, to remind me that a whole world exists out there, even if I can't see it. This month, the team has spoken to a sound engineer proving that less sound isn't necessarily better sound, a professor of disasters and health his new book is bringing Antarctica to a wider audience. And a radar scientist with a novel solution to a problem I didn't even know existed. In each of these stories and invisible world is made visible in a unique and exciting way. In our first story we hear from Molly Rasbash. A second year Arts and Sciences student as she investigates how to really listen to a city.

Molly Rasbash  
Cities are loud. Sound plays a huge role and how you experience in place. Noise.

Andrew Mitchell  
It's the second most impactful environmental health concern behind air.

Molly Rasbash  
But when I'm walking around London, and constantly blocking out the sound with music and podcasts, I was really interested in finding out more about the soundscapes of a city and what they mean. So I spoke to Andrew

Andrew Mitchell  
Mitchell, I'm a research fellow at UCL. And I'm an acoustician. So my background is in physics, specifically actually physics in music. But now my research is focused on soundscape, which is all about all about how people perceive sound, particularly in like real environments. So I focus on urban settings on like urban green spaces, urban parks, streets, every sort of urban public space you can think of. And what we're trying to do is look at how people actually experience and perceive the soundscape in these spaces.

Unknown Speaker  
After working as an acoustic consultant in California, and you became frustrated with the metrics being used to tackle noise in cities, regulation focuses on one measurement - decibels. So all work goes towards limiting volume, hundreds of 1000s of dollars being spent to upgrade buildings to make them quiet inside. Without considering the multitude of factors which contribute to how we experience our environments.

Andrew Mitchell  
The ways that we address noise, just are a little bit myopic, and a bit short sighted and focused on one approach. And on one metric, which is the noise level, which limits us in a lot of different ways.

Molly Rasbash  
Limiting the noise level does not necessarily make a sound environment more pleasurable. This is what a soundscape approach acknowledges in traditional

Andrew Mitchell  
noise control. Typically, what it is is you go out you measure the sound level and then you figure out how do we reduce that noise is a pollutant. And we need to reduce it. Soundscape says sound is a resource. What if we can actually make a space sound better by managing the sound better? Rather than just how do we get rid of negative sounds? What if we introduce positive sounds?

Molly Rasbash  
Let's give you an example. Thinking close to UCL - Russell Square. It's a really nice park, completely surrounded by busy roads with lots of traffic, which makes lots of noise.

Andrew Mitchell  
It has a fountain in the middle. And that fountain when you're sitting there, both because your focus is drawn to it, as opposed to the traffic noise behind you. And just because the sound of the fountain is masking the cars. It sounds much more pleasant when you have the fountain.

Molly Rasbash  
And Andrew has observed that when the fountain is running, people use the park more. From a noise control perspective, this would be an abject failure because all you've added noise, but in practice, using the park is a lot nicer. Andrew is now working in the Bartlett in UCL's Institute for Environmental Design and Engineering. On the soundscape indices. 

Andrew Mitchell  
The goal of the soundscape indices is to create a new more holistic a metric that can hopefully replace decibel, as the new way that we assess the quality of urban public space soundscapes.

Molly Rasbash  
there are so many factors that influence the ways we perceive sound, the visual environment, the expected use of context, for example, the sound of traffic is going to be less annoying next to a road than it would be in a park. Environmental factors like how hot or cold it is, how bright it is, your personal psychological state,

Andrew Mitchell  
so my main role on it, which has gone through my PhD and now into the fellowship is I'm trying to create a computer model that can predict people's perception.

Molly Rasbash  
So how would you even go about doing this? Well, first, you start with data, and lots of it. Andrew and his colleagues would go to different urban locations in London, Venice, Spain, the Netherlands, with partner groups in China doing the same thing.

Andrew Mitchell  
What we do is we stop people as they're coming through. So they're using the space we stop them, Hey, would you mind helping with our research and just filling out this questionnaire on the soundscape? And that questionnaire asked them things like the main one is how do you perceive the sound environment?

Molly Rasbash  
There are eight questions asking from one to five how eventful, uneventful, pleasant, annoying, chaotic, monotonous, vibrant, and calm they found the sound environment.

Andrew Mitchell  
So we take a recording while they were filling out the questionnaire. So this means that we have a one to one matchup of exactly what sound they were exposed to. And then exactly what their assessment was in the actual space. And since I have the measurable quantities that people are exposed to, and I have their perceptual outcome, I can feed that into a computer model, and train a model to read in the measurable features and output, predicted perception.

Molly Rasbash  
This model that Andrew had started creating has the potential to allow architects, city planners, designers and consultants, to understand how spaces will actually be experienced without having to do extensive research, like stopping people in the street. Because sometimes you can't stop people in the street. Like during a global pandemic, which hit right in the middle of Andrews PhD.

Andrew Mitchell  
We're right, right at the height of building this database. And suddenly, it's very illegal to stop people on the street and ask them how do you proceed the soundscape.

Molly Rasbash  
Lockdown actually provided a unique opportunity for this type of research. To find out what happened to cities, when you take away most of the sounds

Andrew Mitchell  
At the point that it hit, I had like an initial version that I'd been testing out and trying to develop a bit more, but I wasn't quite happy with it. But then this happened and we kind of had to be like, it's just, it's the best opportunity. It's the best way to look at the data that we've collected. And I was really hoping it would be like a really good demonstration of what this sort of predictive modelling can achieve that older previous soundscape assessment methods can't.

Molly Rasbash  
And the best case scenario for noise control. Less traffic noise and quieter streets didn't necessarily improve people's experiences of these spaces

Andrew Mitchell  
With a reduction of sound level or reduction of traffic noise in a lot of the spaces but also a corresponding reduction in human presence got more monotonous, so they got more unpleasant. So even though the sound level reduced, they actually got less pleasant.

Molly Rasbash  
Another really important part of Andrew's and the soundscape indices work is a visualisation tool to translate a soundscape - people's perception of sound - into something that you can see and compare. You could even say it's making the invisible, visible. And this tool was made to account for the inherent variation in the way that people experience sound.

Andrew Mitchell  
It gives you like a heat map of the distribution of people who perceived it in a certain way. That then gives you a shape. That is the soundscape perception. That's the shape of that particular soundscape.

Molly Rasbash  
The model Andrew has created has the potential to transform the way we think about look at and listen to cities. The model can be used as an assessment tool to understand how sound is impacting people's lives, and a design tool that will guide interventions and improve the cities we live in. This is so important because

Andrew Mitchell  
cities are for people right? And society is getting more and more urbanised. More and more people will be living in cities.

Molly Rasbash  
But sound doesn't affect us all equally. It's important to recognise that sound and noise control techniques disproportionately impact certain communities within the population

Andrew Mitchell  
noise control. It has a history of being used against underrepresented communities as like a weapon like Robert Moses creating highways through black neighbourhoods in New York.

Molly Rasbash  
And we see that now with the UK common policing bill, criminalising protests because they sound too annoying, it seems obvious to me now, the integral role sounds plays in cities. I never used to think about it. But after speaking with Andrew, I find myself listening all the time. Sound underpins so much of how we experience a place, as well as our quality of life and health. The tools Andrew and UCL sound indices are developing or helping us move towards a city where sound is placed in the centre of its design. If you want to hear more about Andrew's work and other work on sound and cities

Andrew Mitchell  
Podcast with my colleagues at UCL called The Rest is Just Noise. And you can find us wherever you find podcasts.

Molly Rasbash  
I really recommend listening to the rest of just noise and also listening to sound environments around you. Maybe take off your headphones for a while. After this episode, of course.

Cerys Bradley  
We're going to move now from something very close to something quite far away from the city of London where this podcast is being recorded to Antarctica, a place so few of us able to go to Maria Bunyun who was sitting for MSci in Psychology has been exploring the concept of Antarctic kness.

Maria Bunyun  
Antarctica, close your eyes and what do you see? Ice penguins and CEOs. Ilan Kelman, Professor of Disaster and Health at UCL told me that Antarctica is so much more than snow, whales and explorers. He thinks that Antarctica is a place with an ideology. And he calls this ideology Antarcticness. He explores this theme in his book, which discusses Antarctica in relation to the arts, humanities and sciences. I sat down with Ilan to ask him more about Antarcticness and how he conducts his research.

Ilan Kelman  
There are so many ways to frame science. And one way is by location, we can pick a house, we can pick a country, we can pick a continent, or this region or a group of people to find however we wish and do science on that place. But it's really saying, what do we know? What can we think about how can we connect a place of people, the environments together? When we think about these places, some of them are magical, some of them are inspirational. Some of them are mythical. One of the places which may sort of combine all of them, to some extent, is actually what they call the seventh continent, or the southern continent, or the white continent, or then accessible content or the coldest content or the driest continent. There's so many, this is Antarctica. It becomes more than place. It becomes an idea.

Maria Bunyun  
It's an idea because it exists physically, but the world's interaction with it depends so heavily on how we imagined and conceptualise it. Our understanding also relies heavily on how the continent is governed, approached and studied. This is what the book Antarcticness explores - how Antarctica is far more than ice and penguins.

Ilan Kelman  
It's all about the history, the culture, the people, the words and meanings, even something as straightforward as the Antarctic compared to Antarctica, which sounds a bit academic, but we are academics. So we ask these sorts of questions.

Maria Bunyun  
And these themes are explored through the book in a variety of ways through essays, prose, poems, photo essays, and paintings from a variety of authors. Through the many chapters Elon brings to life, the exciting scientific endeavours from Volcanology and Seismology, to the beauty of wilderness and wildlife and its meaning to mankind through to the complicated and evolving History and Sociology of exploration in Antarctica. And to me, this is the beauty of Ilan's work in science, he brings together work and ideas across a range of areas to form a version of Antarcticness. A concept that's evolving, needs nurturing, and is exciting and educational.

It's great to see you how Ilan has put his own stamp on science, and how he really pushes ideas and pushes the limits.

Ilan Kelman  
Science is a generation of knowledge. But what I want to do is not knowledge for knowledge's sake, not explanations for explanation's sake, knowledge and explanations to do better with ourselves. Science for society, knowledge for improvement, explanations to do better. This means bringing people together. This means jumping out of silos. This means recognising that no matter what your background, no matter what your discipline or lack of discipline, no matter what your methods or how you approach your science or your knowledge is we need to work together. So I've always been looking for mechanisms to bring together physical sciences social sciences professions, such as law engineering, social work, medicine humanities, including history, and then all forms of art And having a concept, having a place is one way of doing that.

Maria Bunyun  
I was inspired by this project because it made me think, again about what I've learned and what may cause teachers and what research I've done. More work could be done to be interdisciplinary. It just takes a strong vision. So I asked Ilan, what his process is.

Ilan Kelman  
I go with what I call the ABCs of science, ABC Action, Boldness, Curiosity. If we're not acting, and acting for the betterment of humanity, if we're not bold, through ambition through interdisciplinary, non disciplinary, cross disciplinary transdisciplinary, you know, whatever word you want to use, I tend to use non disciplinary and all disciplinary but I'm happy with the other ones. If we're not bold in that sense, and if we're not driven by our minds, by what we see are not driven by curiosity. What are we doing?

Maria Bunyun  
Landsberg demonstrates the beauty of much of the research happening in Antarctica today. The camaraderie and culture of its work is admirable, as well as international cooperation. However, it hasn't always been this way.

Ilan Kelman  
It started out as people conquering nature, we are going out to explore and yeah, we might die, but that's just the way it is. And literally man, because most of them were men, man against man, the race for the South Pole who's going to win. This is nation versus nation, man against nature because of the harshness that lethality, the exceptionality of that environment. But now, it is governed by the Antarctic Treaty System. It is meant to be a model for international cooperation. It's about everyone working together to recognise that what we do anywhere in the world affects the Antarctic. 

Maria Bunyun  
The themes of sexism, colonialism, heroism, and conquering are explored in the book and authors demonstrate the complete ideological shift that has come about. It's fascinating and informative to read about the wide variety of themes in relation to a single place, Antarctica. Talking with Ilan made me realise how little I knew about Antarctica. Never had I learned about the seventh continent in this way. And I'm sure it's the same for most people. This is why Ilan's book is so important because it portrays the importance of Antarctica. He explained how important it is to educate ourselves, especially for the people who have the power and resources to make changes. On a slightly different level, Ilan is keen to inspire future generations of researchers so they can build on his work.

Ilan Kelman  
As shocking as it may be, I don't know everything. And amazingly, I make mistakes. So get inspired, point out where I've gone wrong, and improve, do better.

Maria Bunyun  
Ilan strikes a perfect balance between academic and inspirational. Talking with him, I could sense his excitement for the future, and how people can follow on from his work, but also how real the future is and how important it is. And whilst this land might seem so far away, and out of reach, it may just be getting ever closer. Not only do our actions have impacts in Antarctica, as seen and ice caps melting and increasing the FOSS rate, and therefore sea level rising felt here at home. We record this episode in the midst of a heatwave and extreme weather warnings. And the cool of Antarctica takes on a whole new meaning. And this is what makes Antarctica even more interesting to me. Will Antarctica ever become livable?

Ilan Kelman  
If human caused climate change continues its current trajectory, then an article will be eminently livable. That will probably be three, four or five centuries in the future, if not more, but it's going to be there. If we do stop human caused climate change, or if there are there are other global changes which keep Antarctica as the highest, driest, coldest, windiest, most remote continent, then again, give ourselves three, four or 500 years and living there will be exciting will be fun. What trajectory are we going to choose? Can we use Antartica as an inspiration to choose a trajectory in which we do not hurt ourselves, the environment or the earth?

Maria Bunyun  
Not only should we consider Antarctica and our future trajectory on Earth. Interestingly, we can think about our findings from Antarctica for further endeavours, namely, Mars. Antarctica is vital for our future, because it tells us so much about humanity and no other area on Earth is governed or treated like Antarctica, and therefore Antarctica can be used to understand how we go about life on Mars.

Ilan Kelman  
Anything we think about penguins and whales in the wild. Why couldn't they be Martians? They're so different from us. But there's also so many similarities- in terms of communication socialisation, other aspects of the lifecycle. So this is where remote does not necessarily need to mean alien

Maria Bunyun  
And so this is what I took away from Ilan, his visionary ideas, his holistic approach and his creativity and education. And so now I want to bring you some sounds of Antarctica all the way from the Australian Antarctic Division.

If you've enjoyed learning about Antarctica as much as I have, then I would recommend checking out elands, book, Antarcticness, inspirations and imaginaries there is a link in the show notes and the PDF is free to download on UCL press. Whilst Antarctica has a wide range of sounds from animal cause to human research to international governance. So far, my sound of Antarctica is Elon and my conversation with him. So I will leave you with one last sound.

Cerys Bradley  
This is Antarctica. And for our final story this week, let's talk about something really invisible, not just far away, let's talk about the part of the light spectrum we cannot see here is Taqwa Sadiq, an MA student in ethnographic and documentary film with a story about the future of radio waves.

Taqwa Sadiq  
Right now, wherever you are, if you are listening to this podcast, that means that you are surrounded by an invisible world, one that we all move through all the time probably without noticing. Even if we don't realise it, it's a word that we are constantly making use of and interacting with. It's what allows my voice to reach your ears in this moment. It's what facilitates every Google search every WhatsApp message, everything we do online, really, this invisible world is the world of radio waves. Or signals being bounced about between different devices.

A lot of us might have learned that at school, but every so often I catch myself thinking, What does that even mean? Where are all of these radio waves flying around? Someone who knows the answer to that question is Dr. Matthew Ritchie lecturer in the electrical engineering department here at UCL. I'm actually looking forward to talking to you about this subject because I was really rubbish at physics at school, fascinated by it just always blows my mind that I can AirDrop something from my phone to my computer and it just pops up. 

Matthew Ritchie  
Yeah, but I think your fascination is certainly something that I always promote over sometimes the know how of the maths and the physics. That desire to learn more is is always the key thing. Dr.

Taqwa Sadiq  
He explained that the technical term for this invisible world of radio waves zooming around all about us is called the radio frequency spectrum.

Matthew Ritchie  
The RF spectrum is very much like say the colour spectrum of the rainbow, which is literally also a spectrum, a different frequency wavelengths produce different colours in visible light. It's take that example of the rainbow and expand it to colours, we can't see - the invisible spectrum that surrounds us as well. And that includes the radiofrequency element of it. And that's the RF spectrum. This is utilised by everyday devices that maybe you just don't typically think about - your phone, your Wi Fi router in your house, the key fob that opens up your car send and receive signals and utilise the RF spectrum.

Taqwa Sadiq  
So radio waves are being used for so much more than just listening to radio on air or walkie talkies. And Dr. Ritchie is working on one particular use of radio waves that has pretty massive opportunity to revolutionise how our devices work, which is radar

Matthew Ritchie  
a radar, which is what I work on uses radio waves. There's a real biological example of a radar type system, and that's a bat. So bats have evolved over millions of years with this capability to sense without their eyes. And they do that by screaming these ultrasonic signals, and then listening with their two ears, and they can then catch their prey successfully with this ability to sense using acoustic So that sound waves, not radiofrequency waves, my field is RF sensing. So sensing is sending a signal often the signal you create, it hits a target or an object that you're trying to detect, and it reflects back and then you you do some processing in order to work out, where is that target? And how fast is it moving, for example,

Taqwa Sadiq  
but what is sending a signal and measuring how it bounces back from a target mean for how we use our devices,

Matthew Ritchie  
Google has a radar product called SOLI. S O L I Google's getting into the radar business. That's, that's fascinating. You know, seeing a massive company, so famous as them to be working on an area that I research in was, was kind of fascinating to me to see what they will do with it. And the amazing thing, or the really interesting thing I found with Google's radar is a small chip was embedded inside the phone with an antenna, and that was in sending and receiving its own signals to sense movements above the phone. Currently, the way we interact with phones is touching their screen, the radar that Google put into their Pixel 4 phone, which was the first phone with a radar built in, aim to recognise hand gestures, you can move very fine gestures of your hand floating above the phone, moving your index finger across your thumb to scroll, we're just rotating your hand very slightly. And this radar was sensitive enough to pick up those signals and interpret them and allow you to control the phone in a new way. So imagine swiping left in the air to skip a track. This is a new type of control that you could do with miniature, or micro or nano radars, maybe within phones. But yeah, they're creating their own signals, and receiving their own signals compared to the communication to the phone, which comes from a broadcast tower down to your phone, and then your phone sends back up to the broadcast tower.

Taqwa Sadiq  
That sounds really futuristic, like this other thing that you would see in the movie. Yeah, yeah,

Matthew Ritchie  
it's very minority report, you know, looking at a screen and swiping your hands left and right in just floating in the air,

Taqwa Sadiq  
all these uses of radars in brilliant. But there is a catch. The RF spectrum where all these radio waves sit

Matthew Ritchie  
it's a finite resource. It's limited, everybody has to share it. The spectrum is finite in a way that light waves travel with a given frequency or defined frequency RF spectra have a range of frequency that might run from from wavelengths that are metres or 10s of metres or hundreds of metres long to wavelengths that are down into perhaps millimetres. Pretty big range then, but still, it's not infinite, they can't produce more of this spectrum is a good analogy to have it as, say real estate or if you have an an island and there's only so big an island, you'd have to carve it up in terms of who uses what sections perhaps. But once those fences are built, perhaps someone wants to extend their property. They might do it unofficially and start encroaching on someone else's land or encroaching on someone else's frequency space. And that can cause serious issues. There was a issue in the US recently where altimeters, radio altimeters, which are devices that look down from planes and tell you how high up they are they encroached slightly on the same frequency bands as 5g. And then this got to a certain point where actually flights were grounded and flights weren't going to fly. When these 5g base stations were turned on.

Taqwa Sadiq  
In the UK, the RF spectrum is regulated by Ofcom, so that different uses of the spectrum are clear which frequencies or what real estate on the radio frequency island they can use. But

Matthew Ritchie  
mobile communication is becoming hungrier and hungrier for wider and wider sections of these bands. So the government itself made a lot of money auctioning off this spectrum selling sections of it so companies can own a part and they get free rein of what to do with that section of the spectrum. But you can't re-auction the spectrum once you've sold it. And it comes back to this finite resource element. So 4g made a lot of lot of money. And then 5g also is made money for the government to sell off the spectrum. But going forward, I think there's going to have to be perhaps a paradigm shift where spectrum is shared. In the future, we're going to butt up against each other more and more when we get these conflicts of multiple devices trying to use the same space that we can operate in same range of frequencies.

Taqwa Sadiq  
So it's not enough to just be clear about who gets to use which parts of the spectrum. What we need to work on now is how to maximise this finite resource.

Matthew Ritchie  
And some of my research that I work on is how can we best do multiple tasks with this limited resource and how can we use it flexibly?

Taqwa Sadiq  
Dr. Ritchie's research is developing a specific piece of hardware to be more efficient and smarter in the way we make use of the spectrum.

Matthew Ritchie  
We're kind of coining it as a Swiss army knife, RF tool, RF meaning radio frequency, because what we want to do is programme it up. So it's super flexible and can do lots of different jobs, which would traditionally be done by very individual and very separate devices. But by making a single device that can do multiple roles,

Taqwa Sadiq  
you can be a lot more efficient with how you use the RF spectrum. Now, this swiss army knife RF tool is pretty complicated. And as the name suggests, it can do a lot of different things. But one of the most attractive features is how it uses passive radar.

Matthew Ritchie  
So a passive radar uses someone else's signal to detect targets might be the Wi Fi router in your house that allows your laptops and your phones to get emails and stream Netflix. But the fact that it's sending a signal, it's an RF signal or radio frequency signal. And it's kind of illuminating your room like a lighthouse really, with these signals. And radar engineers have kind of pondered, well, there's a signal there, I don't have to make my signal because someone else has created it for me. So why don't I try and use that signal that's already there. And now we can detect people walking around, just with the Wi Fi signals that come out from your own router. And it can almost be considered as a green radar that's not contributing to a more congested RF environment, because it's it's reusing signals that are already there.

It sounds really cool. And then I'm still just stuck on that all of this is happening because of waves. It's amazing. Before speaking to Dr. Ritchie, I assume that whatever is literally in the ether, that allows my wireless keyboard or my phone to communicate was just infinite. I kind of took it for granted that there'd always be space for all these signals to be flying around. I had no idea that this the RF spectrum is limited, finite, that it can become congested, or parts of it can be sold or owned. And as Dr. Ritchie explained, we need to be more sustainable in how we design our devices going forward to be more efficient and creative, in order to maximise this invisible world that powers so much of our lives every day.

Cerys Bradley  
It's a big world out there. It exists beyond the city that we live in and the world that we can see and we can learn a lot about it if we can learn to look and listen a little differently. Thank you for listening to the fourth episode of season three. We'll be back next month with more stories from the UCL community. In the meantime, if you want further information on any of the projects featured in today's episode, you can check out the show notes for links, pictures and more. You've been listening to me at UCL the podcast to listen to previous episodes or find out more about life at UCL visit www.ucl.ac.uk forward slash made dash app dash UCL or subscribe wherever you listen to this podcast. This episode was presented by myself Cerys Bradley with storage from Molly Rasbash, Maria Bunyun and Taqwa Sadiq. It was produced by Halle McCarthy with support from UCL and featured theme music from the blue dot sessions. For a full list of audio credits, please see the show notes. Special thanks to Andrew, Ilan and Matt, for sharing their research with us. This podcast is brought to you by UCL Minds, bringing together UCL knowledge, insights and expertise through events, digital content and activities that are open to everyone. See you next month.