Wi-Fi is an integral part of modern connectivity, enabling wireless data transmission in homes, workplaces, and public spaces. Operating in the microwave range of the electromagnetic spectrum, it typically functions at frequencies of 2.4 GHz or 5 GHz. Despite its importance for internet access, Wi-Fi signals remain invisible to the human eye because they lie outside the visible light spectrum, requiring specialized equipment to detect.
The XJ9 radio telescope, created by Justin Atkin from The Thought Emporium YouTube channel, addresses this limitation by capturing and visualizing Wi-Fi signals. Using a software-defined radio (SDR) and a movable antenna system, the XJ9 measures Wi-Fi signal strength at different points. Justin's setup utilizes a HackRF for signal detection. These measurements are then transformed into visual representations, resembling heatmaps, to display the strength and distribution of Wi-Fi signals in a given area. Built with geared stepper motors, a swappable antenna head, and precision components, the XJ9 offers a robust and scalable platform for analyzing electromagnetic radiation within the Wi-Fi spectrum.
Inspired by radio astronomy, where massive deep-space telescopes map cosmic phenomena through microwave frequencies, the XJ9 applies similar methods to local environments. It provides detailed spatial mapping and signal analysis of Wi-Fi networks, adapting techniques from space exploration for practical, everyday use.
This project showcases the potential for better understanding electromagnetic environments and demonstrates how advanced scientific principles can be applied to common technological challenges. More information is available in Justin’s YouTube video, which includes links to the open-source 3D files for building the XJ9 on GitHub.