The drones began crashing on Ukraine’s front lines, with little explanation.

For months, the aerial vehicles supplied by Quantum Systems, a German technology firm, had worked smoothly for Ukraine’s military, swooping through the air to spot enemy tanks and troops in the country’s war against Russia. Late last year, machines began to fall from the sky when they were returning from missions.

“It was this mystery,” said Sven Kruck, a Quantum executive who received a stern letter from Ukraine’s Ministry of Defense demanding a fix.

Quantum’s engineers soon homed in on the issue: Russians were jamming the wireless signals that connected the drones to the satellites they relied on for navigation, leading the machines to lose their way and plummet to earth. Quantum’s engineers developed software powered by artificial intelligence to act as a sort of secondary pilot. A manual option was also added so that the drones can be landed using an Xbox controller. The company also built a service center to monitor Russia’s electronic attacks.

“All we could do is get information from the operators, try to find out what wasn’t working, test and try again,” Mr. Kruck stated.

Radio signals are used in Ukraine to disrupt the communication between drones, troops and their commanders, to locate targets and to fool guided weapons. The tactics, known as electronic warfare, have become a cat and mouse game between Russia, Ukraine and engineers.

“Electronic warfare has impacted the fighting in Ukraine as much as weather and terrain,” Bryan Clark is a senior fellow of the Hudson Institute – a Washington think tank. He said that now, every operation in a war must take into account the enemy’s moves on the electromagnetic spectrum.

Since more than 100 year, electronic warfare has played a role in wars. Winston Churchill called it the “German Radio Deception” during World War II. The British used German radio signals in order to fool bomber targeting systems. “battle of the beams.” In the Cold War the Soviet Union heavily invested in electronic weapons, gaining an asymmetrical advantage over the missiles and aircraft of the United States.

In recent decades the use of electronic defense and attack has become more imbalanced. In the Iraq War in the 2000s the United States used gadgets known as jammers to create such a lot of radio noise that improvised bombs could not communicate with the remote detonators. Israel has recently mangled GPS signals with electronic warfare systems in its airspace to confuse drones and missiles.

The conflict in Ukraine was the first in recent history where two relatively large armies used electronic warfare capabilities and evolved the techniques in real-time. Originally the domain of experts, these technologies are now being used by frontline infantry troops. Ukrainian drone pilots claimed they were constantly adjusting their tactics to combat invisible attacks. Some people said a new frequency of radio might work. Then, another antenna.

The tactics have become so critical that electronic warfare received its own section in a recent essay by Gen. Valery Zaluzhny, Ukraine’s top military commander. “Widespread use of information technology in military affairs” It is essential to end the current impasse in the conflict against Russia.

Experts said that these techniques have transformed the war into an experimental field where the United States and Europe have closely observed to see what might influence a future conflict.

Gen. Charles Q. Brown Jr., Chairman of the Joint Chiefs of Staff and a member of Congress, addressed the issue of electronic war in prepared remarks at a Congressional hearing this year. Thomas Withington is an expert in electronic warfare at the Royal United Services Institute.

“The war in Ukraine has been the performance enhancing drug for NATO’s electromagnetic thinking,” He said. “It has been the thing that concentrates minds.”

As Russian tanks rolled toward Kyiv in February 2022, the Russian military initially made good on its reputation as one of the world’s best at electronic warfare. The Russian military used powerful decoys and jammers to overwhelm Ukrainian air defenses. Ukraine was left reliant on aircraft in order to combat Russian planes.

Initially, they do not seem dangerous. They can be satellite dishes or antenas mounted on trucks, fields or buildings. They then emit electromagnetic waves that track, trick and disrupt sensors and communication links used to guide precision weapons or allow radio communication. Almost all communication technologies rely on electromagnetic waves, whether it’s soldiers using radios, pilots communicating with drones or missiles connected to satellites.

Jammers are a simple but effective way to disrupt communications. They send out powerful signals that interfere with the transmission of signals. The sound of heavy metal during a college lecture is similar to jamming.

A key weapon can send a fake signal, such as a satellite connection. This fake signal is called spoofing and can trick a drone or missile into believing it has strayed miles from its intended course. In other cases, spoofers ape the signals made by missiles or planes to trick air defense systems into detecting attacks that aren’t happening.

Other tools are used to listen for radiation beams and try to find their source. These devices can be used to locate and attack drones.

Analysts said that after early successes with these tools, Russia’s military has stumbled. The Russian military has been experimenting with smaller electronic weapons such as anti-drone weapons and small jammers which create a radio-wave shield around trenches.

“The Russians have been more nimble at responding than we would have expected from their ground behavior,” James A. Lewis said, a former U.S. Official who writes about technology and security for Center for Strategic and International Studies (CSIS) in Washington. “That should be worrisome for NATO.”

The Kremlin didn’t respond to our request for a comment.

To combat Russia’s century of Soviet know-how in electronic attack and defense, Ukraine has turned to a start-up approach associated with Silicon Valley. The idea is to help the country’s tech workers quickly turn out electronic warfare products, test them and then send them to the battlefield.

This summer, Ukraine’s government hosted a hackathon for firms to work on ways to jam Iranian Shahed drones, which are long-range unmanned aerial vehicles that have been used to hit cities deep inside the country, said Mykhailo Fedorov, Ukraine’s digital minister.

On testing ranges just outside Kyiv, drone manufacturers pit their machines against electronic weapons. Yurii Momot (53), a former Soviet Union commander of special forces and founder of electronic warfare company Piranha, demonstrated a new anti drone gun in a central Ukrainian field in August.

The guns have a checkered performance in the war, but Mr. Momot’s version worked. He pointed it at the DJI Mavic drone, which is a cheap, common reconnaissance drone. The drone hovered in place. The gun’s radio signal burst had overwhelmed its navigation system.

“The whole system is more structured in Russia,” Mr. Momot said of Russia’s electronic warfare program, which he knows from his time with the Soviet army. “We’re catching up, but it will take a while.”

Other Ukrainian firms, like Kvertus and Himera are building walkie talkies or tiny jammers that can resist Russian jamming.

At Infozahyst, one of Ukraine’s biggest electronic warfare contractors, engineers recently worked on a project to track and identify Russian air defense systems. Iaroslav Kalinin, the company’s chief executive, said Russia’s anti-aircraft radars were not as easy to replace as tanks. It is possible that if the Russian anti-aircraft radars are eliminated in sufficient numbers, they could turn the tide of war.

“Once we control the sky, then Russia fails hard,” He said.

This summer, Oleksandr Berezhny, a Quantum executive, traveled with one of Ukraine’s top drone pilots to share what they knew about electronic warfare with NATO. They explained their problems to an audience of commanders at a large table in a German base.

“We told them probably 90 percent of the American and European systems coming to Ukraine were not prepared to meet the electronic warfare challenge,” Mr. Berezhny said. “There was total understanding that something needed to change.”

Ukraine has shown how future electronic wars could be fought. Several European and American experts are concerned that they have not responded quickly enough. Chinese experts also thoroughly documented which Russian electronic attack was most effective against NATO system, and in turn where Russia failed.

In one November 2022 report, a Chinese defense think tank detailed how a Russian electronic attack had tricked NATO’s detection equipment, leading Ukraine to reveal the location of its own electronic defenses.

“The Russian army’s anti-drone combat capabilities are superior to those of the U.S. military,” The report stated.

Clark, of the Hudson Institute, stated that as Ukraine develops its anti-jamming technologies, some of these tactics are being exported to the United States, and its allies.

“Now you’re starting to see countries, including the United States, field these smaller systems, just like you’re seeing folks in Ukraine cobbling them together,” He said.

For many on Ukraine’s front, the improvements can’t come fast enough.

“Even if you make your drone invisible, your controller and your antenna give out a signal,” One Ukrainian drone pilot who only gave his first name Vladislav said. Russians can detect an area of 200 square meters in which a drone pilot could be. He added that artillery once came within this window. “about 15 to 20 meters” He was hit by a person.

“It’s not possible to hide completely,” He said.

Olha Kotiuzhanska Reporting from Kyiv Dnipro Odesa Ukraine. Arijeta lajka provided video productions from New York.