- Russia is building a large antenna array near Poland in Kaliningrad for signal interception
- The site, identified in 2023, features concentric circles and radial roads inside a fenced perimeter
- The Circularly Disposed Antenna Array (CDAA) aids in detecting and tracking radio signals
Russia is building what appears to be one of Europe's largest antenna arrays, a system capable of intercepting signals across the continent and beyond.
The site, 25 km from Poland's border, is believed to be somewhere in the forests of Kaliningrad. It has several concentric circles, radial roads, and a central area, all inside a fenced perimeter.
Researchers first identified the site in 2023 using satellite imagery. The Russian open-source intelligence research group Tochnyi first highlighted the site.
Open-Source Intelligence (OSINT) analysts, including Radio and Nukes1 and Planes and Stuff2, also examined the site and shared findings online. They pointed out its size, shape, and location as signs it could have a military purpose.
The site appears to be a Circularly Disposed Antenna Array (CDAA). These systems detect radio signals and determine their direction. Militaries used Circularly Disposed Antenna Arrays during the Cold War for submarine communication, surveillance, and signal tracking. Each array has rings of vertical antennas, and the spacing and size of the rings control which frequencies it can receive.
Construction started over two years ago. Satellite images show that by mid-2025, Russia has finished the perimeter walls, built radial roads, and prepared areas for antennas. Analysts estimate the Kaliningrad array may reach 1,600 metres across, which is larger than most other arrays in the world.
Kaliningrad hosts the Baltic Fleet, S-400 surface-to-air missile defence systems, and nuclear-capable Iskander ballistic missiles. This array will allow Russia to monitor North Atlantic Treaty Organisation (NATO) communications in Eastern Europe and the Baltic Sea. It can also help Russia communicate with submarines using very low-frequency signals.
The array uses a design based on the Soviet-era Krug system, which came from German Wullenweber technology. The Kaliningrad site shows that Russia combines older methods with current military needs in signals intelligence and electronic warfare.
Even under construction, the Kaliningrad array shows Russia's intent to maintain intelligence dominance. Only 25 km from NATO territory, it gives Moscow a powerful listening post on Europe's doorstep.
NATO is a military alliance of mostly North American and European countries. Russia has never been a member. NATO was reportedly originally formed during the Cold War partly to counter the influence of the Soviet Union, of which Russia was the main part.
