Secret Signals

China’s ambitions to expand its global intelligence-gathering capabilities have drawn it to the doorstep of the United States. In a striking revelation last year, Biden administration officials disclosed that China has access to multiple spy facilities in Cuba. While China’s activities on the island remain shrouded in secrecy, satellite imagery analyzed by CSIS provides the latest and most comprehensive assessment of where China is most likely operating.

Sitting less than 100 miles south of Florida, Cuba is well positioned to keep watch on sensitive communications and activities in the region, including those of the U.S. military.

The southeastern seaboard of the United States brims with military bases, combatant command headquarters, space launch centers, and military testing sites.

Cuba has a long history of hosting foreign espionage operations targeting the United States. During the Cold War, the Soviet Union operated its largest overseas intelligence site at the Lourdes Signals Intelligence Complex.

Rumors of China snooping from the island have simmered for decades. The issue resurfaced in mid-2023 amid media reports of a Chinese “spy base” near Havana.

Satellite imagery and open-source information assessed by CSIS offers an unprecedented look at four active sites in Cuba capable of conducting electronic surveillance operations.

These four sites are among the most likely locations supporting China’s efforts to spy on the United States.

Signals intelligence (SIGINT) is a core element of modern spycraft. Intercepting signals transmitted by both civilian and military actors can provide countries with valuable information about their adversaries, competitors, and allies alike.

Collecting SIGINT is a complex task that requires specialized equipment, namely antennas, optimized for the signal characteristics of their targets. The size, number, orientation, and layout of these antennas determine their capabilities and function.

Basics of Beamforming

A single isotropic antenna receives signals from all directions, providing a wide coverage area but limiting its ability to focus the signal’s direction.

Two antennas can be synchronized to create a stronger, focused beam that reduces interference. This is called “beamforming.”

Beamforming can be further refined with more antennas. Adjusting the phase and amplitude of signals at each antenna allows for precise control over the beam.

Organizing the antennas into a grid allows for steering the beam without the need to physically move the antennas.

Antennas arranged in a configuration known as a circularly disposed antenna array (CDAA) allow for 360-degree beamforming capability. CDAAs are highly effective at determining the origin and direction of incoming high-frequency signals and were commonly used by both the United States and Soviet Union during the Cold War.

Other types of antennas are also used for SIGINT.

Dish antennas can focus radio waves into a narrow beam, making them effective for communicating with satellites far from the earth, as well as intercepting and collecting signals from a variety of sources. Radar antennas emit and receive radio waves to track physical objects, such as ships, aircraft, and missiles.

Geography impacts the effectiveness of SIGINT. Over long distances, radio signals can become difficult to isolate from surrounding signal traffic. Radar transmissions generally require a direct “line of sight” to the target, leading to limitations caused by the curvature of the Earth and other physical obstacles.

Cuba’s proximity to the southern United States and the Caribbean makes it a prime location for collecting SIGINT on the region. For Beijing, having access to SIGINT capabilities in Cuba would open a significant intelligence window inaccessible from within Chinese territory.

The following four SIGINT sites in Cuba are strategically located to spy on the United States.

Bejucal

22° 56’ 54.5”N 82° 21’ 46.29”W

Nestled in the hills overlooking the capital city of Havana is the largest active Cuban SIGINT site reviewed by CSIS. Located near Bejucal, the complex gained notoriety during the Cold War for housing Soviet nuclear weapons in the 1962 Cuban Missile Crisis.

For decades, Bejucal has been subject to suspicion for its possible ties to Chinese intelligence activity, including in English and Spanish-language media reporting, U.S. congressional testimony, and unclassified government documents.

It even featured in the 2016 U.S. presidential primary debates, when Florida senator Marco Rubio called on Havana to “[kick] out this Chinese listening station in Bejucal.”

Satellite imagery from March 2024 reveals that the area has undergone major updates over the past decade — a clear indication of an evolving mission set. This includes the construction of a mysterious new radome that may contain a radar or ELINT system.

El Salao

20° 0’19.16”N 75°44’48.49”W

On the opposite side of the island is a new SIGINT complex that has previously gone unreported. There have been numerous unverifiable sources asserting that China has operated a large antenna field in the country’s far eastern province of Santiago de Cuba since 1999. Access to such an outpost would provide China with a highly strategic vantage point near Naval Station Guantanamo Bay, a key U.S. military base in the region.

CSIS analyzed satellite imagery covering 2,900 square kilometers of the province but did not find such a facility. However, CSIS did uncover a significant new SIGINT collection site under construction just east of the city of Santiago de Cuba, near a neighborhood called El Salao. The structure, whose construction began in 2021, appears to be a large CDAA with a projected diameter of 130 to 200 meters.

Once operational, this CDAA will serve as a powerful tool for enhancing air and maritime domain awareness in the region, where the U.S. military and its international partners operate regularly. Some CDAAs of this approximate size are reportedly able to track signals anywhere from 3,000 to 8,000 nautical miles away.

Sites like these were a staple of SIGINT during the Cold War. As hostilities between the two superpowers faded and new technologies emerged, Russia and the United States decommissioned or abandoned most of their CDAAs. China, however, has been actively building major new CDAAs, including on its militarized outposts on Mischief Reef and Subi Reef in the South China Sea.

Wajay

23° 0’27.63”N 82°25’13.48”W

Less than 10 kilometers north of Bejucal lies a smaller facility known as Wajay. The presence of security fencing and two guard posts strongly suggests that the site is intended for military or other sensitive activities.

The compound has gradually expanded over the past 20 years, growing from just one antenna and several small buildings in 2002 to a robust complex today. It now hosts 12 antennas of various sizes and orientations, significant operations and support facilities, and even a small solar farm.

Unsubstantiated rumors suggest that China played a role in either the site’s construction or its modernization.

No dish antennas are visible here, suggesting its purpose is primarily terrestrial signal interception and transmission. However, the variety of antennas present is a clear indication that Wajay is responsible for a reasonably complex SIGINT mission set.

Calabazar

23° 0’48.87”N 82°19’58.91”W

Close by, a small Cuban military complex (which is associated with the name of the nearby town of Calabazar in declassified U.S. government documents) bears the hallmarks of SIGINT operations. Over a dozen dish antennas of varying sizes are scattered throughout the secured location alongside two visible pole antenna arrays. As is often the case with military intelligence installations, the number, location, and orientation of the antennas have shifted considerably over time, likely adjusting to changes in the site’s mission set. The newest dish was installed in 2016.

Without access to classified materials, pinpointing the specific targets of these assets is nearly impossible. Nonetheless, the growth of space-monitoring equipment at sites like Bejucal and Calabazar is notable given that Cuba lacks its own satellites or space program. While it could operate downlink capabilities to access satellite data for a range of applications, the types of space-tracking capabilities observed are likely intended to monitor the activities of other nations (like the United States) with a presence in orbit.

Even limited access to this equipment would provide China a far greater ability to monitor and communicate with its own space assets passing above the other side of the globe. Like the United States, Russia, and Europe, China operates a global network of ground stations from which it can conduct telemetry, tracking, and command (TT&C) on its satellites and spacecraft.

China has historically lacked access to ground stations in North America. Accessing installations in Cuba could help close that gap.

Cuban facilities would also provide the ability to monitor radio traffic and potentially intercept data delivered by U.S. satellites as they pass over highly sensitive military sites across the southern United States. Florida alone is home to the major space-launch complex at Cape Canaveral, the headquarters of both the U.S. Southern Command and Central Command, and multiple submarine and other bases.

Key Bases and Installations in Florida

Collecting data on activities like military exercises, missile tests, rocket launches, and submarine maneuvers would allow China to develop a more sophisticated picture of U.S. military practices. While modern military communications are highly encrypted — meaning the contents of the messages and data are hidden — information on the frequency, origin, direction, and pace of communications traffic can provide significant intelligence value.

Other types of data can be collected with less concern for encryption. Notably, ELINT and radar systems, like the one possibly installed at Bejucal in recent years, are within range to monitor rocket launches from Cape Canaveral and NASA’s Kennedy Space Center.

Studying these launches — particularly those of SpaceX’s Falcon 9 and Falcon Heavy reusable first-stage booster rocket systems — is likely of keen interest to China as it attempts to catch up to U.S. leadership in space launch technology.

Intercepting the flow of commercial communications through vital economic centers across the southern United States could provide a treasure trove of data less restricted by encryption. The region hosts major research and manufacturing centers for industries such as aerospace, electronics, biotechnology, and other key strategic sectors prioritized by Beijing.

Beijing has clear political and ideological motivations to keep afloat one of the world’s few remaining Communist Party–led governments. Yet its interests there are also clearly strategic.

China’s ambitions to expand its overseas military presence are well documented, and Cuba provides an attractive foothold for the People’s Liberation Army (PLA) in the Caribbean. An unclassified assessment by the U.S. Office of the Director of National Intelligence released in February 2024 lists Cuba as one of several countries where China is looking to establish military installations.

Cuba is currently embroiled in its worst economic crisis since the fall of the Soviet Union, and Havana is in desperate need of external assistance. China has emerged as a critical lifeline, providing billions in debt relief and direct assistance in recent years.

China-Cuba Military Ties

Beijing-tied firms are also deeply embedded in Cuba’s technology sector. Chinese tech giants Huawei and ZTE — both blacklisted by the U.S. government over espionage risks — now form the backbone of Cuba’s telecommunications infrastructure. Frequent technical exchanges between Cuban and Chinese state-backed universities and technology firms likewise facilitate technology transfer.

The PLA and Cuban Revolutionary Armed Forces (FAR) have maintained regular high-level exchanges since 1999. Most recently, in April 2024 the FAR’s most senior political leader met with a top PLA official in Beijing.

While there is no official arms trade between the countries, China has been implicated in illicit weapons transfers to Cuba. Most notably, in 2015 a Chinese civilian-flagged cargo vessel carrying explosives and munitions bound for Cuba was intercepted by Colombian police.

Detailed information about China’s presence in Cuba is scarce, and decades of speculation have made it difficult to decipher reality from rumors. Yet there are growing signs that China’s economic and political leverage may be opening doors for its military and intelligence services in Cuba. Even if China does not have direct access to facilities there, the data collected by Cuban counterparts could be readily shared with Beijing.

Cuba’s revival as a key player in U.S. strategic competition should raise concerns in Washington and beyond. While China is unlikely to seek to establish major offensive capabilities on the island in the short term, the gradual expansion of its presence there will remain an enduring concern for policymakers in the United States and its regional partners.

Matthew P. Funaiole is vice president of iDeas Lab, Andreas C. Dracopoulos Chair in Innovation and senior fellow of China Power Project at the Center for Strategic and International Studies (CSIS). He specializes in using data-driven research to unpack complex policy issues, specifically those related to Chinese foreign and security policy, cross-Strait relations, and maritime trade.

Aidan Powers-Riggs is a research associate for China analysis with the iDeas Lab at CSIS, where he primarily supports the Hidden Reach special initiative. Previously, he researched China’s foreign and security policies and U.S.-China tech competition at the National Bureau of Asian Research (NBR), the Asia Society Policy Institute, the China Power Project at CSIS, and the Senate Foreign Relations Committee.

Brian Hart is a fellow with the China Power Project at CSIS. He also helps to lead Hidden Reach, a CSIS special initiative that shines light on underappreciated sources of China’s influence through open-source data and satellite imagery. Brian’s research focuses primarily on Chinese foreign and security policy, Chinese military modernization, U.S.-China relations, and Taiwan security issues.

Henry Ziemer is a research associate with the Americas Program at CSIS, where he supports the program’s research agenda and coordinates event planning and outreach. His research interests include transnational organized crime and human rights and security in Central America.

Joseph S. Bermudez Jr. is an internationally recognized analyst, award-winning author, and lecturer on North Korean defense and intelligence affairs and ballistic missile development in developing countries. He is concurrently senior fellow for Imagery Analysis at CSIS; senior adviser and imagery analyst for the Committee for Human Rights in North Korea (HRNK); author for IHS Markit (formerly the Jane’s Information Group); and publisher and editor of KPA Journal.

Ryan C. Berg is director of the Americas Program and head of the Future of Venezuela Initiative at CSIS. He is also an adjunct professor at the Catholic University of America and visiting research fellow at the University of Oxford’s Changing Character of War Programme. His research focuses on U.S.-Latin America relations, authoritarian regimes, armed conflict, strategic competition, and trade and development issues. He also studies Latin America’s criminal groups and the region’s governance and security challenges.

Christopher Hernandez-Roy is the deputy director and senior fellow of the Americas Program at CSIS. Throughout his more than 25-year career, Mr. Hernandez-Roy has worked extensively to advance democratic governance, prevent and resolve conflict, strengthen the rule of law, respect human rights, ensure citizen security, and promote integral development across Latin America and the Caribbean. He has held various senior leadership positions at the Organization of American States (OAS), having served as a senior political adviser to two secretaries general.