Eric Acuña
L-Band Dreamcatcher
This project began with a simple collision of ideas: dreamcatchers and satellite radio.
I wanted to build an antenna that wasn't only a functional object, but also carried a metaphor. A dreamcatcher is traditionally associated with filtering and catching dreams. I wondered what would happen if that idea were translated into an antenna — an object designed to catch something invisible, but very real.
So I began building.
fig 1. experimentations for the copper dreamcatcher field.
The dish became the first part of the experiment. Copper wire, normally hidden away inside cables and electronics, became part of the visible structure. I began weaving and spooling it into a form inspired by a dreamcatcher, while adapting the geometry for receiving L-band signals.
From there, the project became a rabbit hole into satellite communications, feeds, radio hardware, software-defined radio, and the many things that can be received from above.
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Satellite communications and orbital feeds
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Radio hardware and fabrication
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Software-Defined Radio (SDR) and data decoding
fig 2. Creation of the 9 turn helix feed using 8mm copper, a wooden recorder, some telescope components, and console tape
One of the technical starting points was The Bald Geek's L-Band antenna work, which helped me understand the feed horn, helix, reflector, and some of the practical fabrication involved in building an L-band receiving system.
Another path led me to Outernet / Othernet, where the idea of receiving information broadcast from satellites opened up an entirely different direction for the project. I'm still learning how that system works and what I ultimately want to do with it. That's intentional. This isn't a finished antenna, but more of a learning instrument. A physical experiment in turning invisible signals into something I can see, hear, understand, and eventually perhaps build upon.
The Deployment Strategy: Designing a Collapsible Reflector
An L-band satellite antenna needs a significant surface area to catch weak signals, but a rigid, full-sized metallic dish can be bulky, heavy, and difficult to transport. To keep this project agile, portable, and experimental, I wanted a reflector that could deploy in seconds and fold down into a backpack when not in use. The solution came from combining an ordinary umbrella skeleton with high-performance Faraday fabric.
fig 3. Collapsible reflector made from umbrella skeleton and Faraday fabric
It feels counterintuitive to point a piece of cloth at space and expect it to bounce radio waves, but electromagnetic physics works in our favor here.
To a high-frequency satellite transmission, your fabric doesn't look like cloth at all—it looks like a solid sheet of pure metal.
1. Overcoming the Grid Size (The Mesh Rule)
For a material to successfully reflect a radio wave, it doesn’t need to be completely solid. It just needs a grid structure with openings that are significantly smaller than the signal's wavelength.
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The L-Band Wavelength: An L-band satellite signal operating around 1.5 GHz has a physical wavelength of roughly 20 centimeters.
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The Shielding Metric: The micro-fine conductive grid woven into Faraday fabric has openings measured in fractions of a millimeter. Because 20 centimeters is vastly larger than the microscopic weave of the cloth, the fabric acts as a near-perfect electromagnetic mirror, reflecting almost 100% of the radio energy.
When the umbrella frame is pushed open, the fabric is pulled into a curved surface. When parallel radio waves streaming down from an orbital satellite hit this metallic dish, they don't bounce straight back up. Instead, the curve redirects them inward, focusing all that scattered energy onto a single hot-spot along the umbrella's central mast.
3. Tuning the Feed Mount
While the umbrella skeleton proved the concept of a lightweight, deployable shape, it lacked structural rigidity and the precise, smooth curve necessary to maximize signal collection. To push the boundaries of both the aesthetic and the engineering, I moved away from the umbrella shaft entirely and designed a dedicated DIY parabolic dish with an integrated, custom-built feed mast.
fig 3. Collapsible reflector made from umbrella skeleton and Faraday fabric
Replacing the umbrella shaft with this hybrid structure introduces several key engineering improvements while preserving the core metaphor of the project.
1. True Parabolic Focus vs. Segmented Fabric
The umbrella fabric formed rough, flat triangles between its metal ribs, creating an imperfect reflector. Replacing it with a smooth, solid metallic dish creates a true parabolic curve. This ensures that every radio wave striking the surface is focused with near-perfect geometric accuracy toward the center axis, drastically improving the signal gain.
2. The Weave as an Electromagnetic Ground Plane
By anchoring the copper wire web directly to the dish, the web effectively becomes part of the reflector's surface area. The metal dish and the woven wire work in unison as an electromagnetic boundary layer, reflecting the 20-centimeter waves back toward the helix feed.
3. The Wooden Recorder as a Low-Interference Mast
Using a wooden recorder as the boom is a functional choice. In radio design, metal structures placed directly in the signal path can warp or block the incoming waves, creating unwanted reflections and noise.
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RF Transparency: Wood is an organic, non-conductive material. At L-band frequencies, it acts as a dielectric that is relatively transparent to radio waves.
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The Helical Core: The straight, rigid cylindrical body of the recorder provides a perfect structural core to wind the copper helix at a precise, consistent pitch. This ensures the antenna maintains its polarization and matches the specific rotational path of the satellite signals descending from space.
4. The Complete Instrument
By mounting the entire assembly onto a base equipped with a dedicated viewing screen, the project shifts from a loose pile of hardware to a cohesive, unified laboratory instrument. The signals caught by the wire web are focused by the dish, captured by the helix wound around the wooden recorder, and sent down to the internal receiver to be translated immediately into visible data.
fig 4. image of the galactic plane over Gardner State Park
The Next Steps: Iteration and Field Research
To push the L-Band Dreamcatcher to its full potential, my current focus is divided into two main areas:
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Prototyping Varied Geometries: I am currently designing and constructing several distinct prototypes. Each version will experiment with different dish depths, variations in the copper wire weaving density, and alternative pitches for the recorder-mounted helix feed to see how physical adjustments alter the reception quality.
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Establishing a Field Testing Environment: Because local structures, indoor electronics, and urban environments create significant radio frequency (RF) noise, true testing requires open skies. I am planning a series of field research trips to remote locations. Testing the prototypes in these electromagnetically quiet environments will allow me to capture raw, uncorrupted satellite data streams.
By taking these prototypes out into nature, the goal remains the same: to find out exactly what these invisible signals look like when they are finally caught in the web.