Meet the radio-obsessed civilian shaping Ukraine’s drone defense

Serhii “Flash” Beskrestnov hates going to the front line. The risks terrify him. “I’m really not happy to do it at all,” he says. But to perform his particular self-appointed role in the Russia-Ukraine war, he believes it’s critical to exchange the relative safety of his suburban home north of the capital for places where the prospect of death is much more immediate. “From Kyiv,” he says, “nobody sees the real situation.”

So about once a month, he drives hundreds of kilometers east in a homemade mobile intelligence center: a black VW van in which stacks of radio hardware connect to an array of antennas on the roof that stand like porcupine quills when in use. Two small devices on the dash monitor for nearby drones. Over several days at a time, Flash studies the skies for Russian radio transmissions and tries to learn about the problems facing troops in the fields and in the trenches.

He is, at least in an unofficial capacity, a spy. But unlike other spies, Flash does not keep his work secret. In fact, he shares the results of these missions with more than 127,000 followers—including many soldiers and government officials—on several public social media channels. Earlier this year, for instance, he described how he had recorded five different Russian reconnaissance drones in a single night—one of which was flying directly above his van.

As well as the frontline information he shares on his public channels, he runs a “support service” for almost 2,000 military communications specialists on Signal and writes guides for building anti-drone equipment on a tight budget. “He’s a celebrity,” one special forces officer recently shouted to me over the thump of music in a Kyiv techno club. He’s “like a ray of sun,” an aviation specialist in Ukraine’s army told me. Flash tells me that he gets 500 messages every day asking for help.

Despite this reputation among rank-and-file service members—and maybe because of it—Flash has also become a source of some controversy among the upper echelons of Ukraine’s military, he tells me. The Armed Forces of Ukraine declined multiple requests for comment, but Flash and his colleagues claim that some high-ranking officials perceive him as a security threat, worrying that he shares too much information and doesn’t do enough to secure sensitive intel. As a result, some refuse to support or engage with him. Others, Flash says, pretend he doesn’t exist. Either way, he believes they are simply insecure about the value of their own contributions—“because everybody knows that Serhii Flash is not sitting in Kyiv like a colonel in the Ministry of Defense,” he tells me in the abrasive fashion that I’ve come to learn is typical of his character. 

But above all else, hours of conversations with numerous people involved in Ukraine’s defense, including frontline signalmen and volunteers, have made clear that even if Flash is a complicated figure, he’s undoubtedly an influential one. His work has become greatly important to those fighting on the ground, and he recently received formal recognition from the military for his contributions to the fight, with two medals of commendation—one from the commander of Ukraine’s ground forces, the other from the Ministry of Defense. 

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Despite a small number of semi-autonomous machines with a reduced reliance on radio communications, the drones that saturate the skies above the battlefield will continue to largely depend on this technology for the foreseeable future. And in this race for survival—as each side constantly tries to best the other, only to start all over again when the other inevitably catches up—Ukrainian soldiers need to develop creative solutions, and fast. As Ukraine’s wartime radio guru, Flash may just be one of their best hopes for doing that. 

“I know nothing about his background,” says “Igrok,” who works with drones in Ukraine’s 110th Mechanized Brigade and whom we are identifying by his call sign, as is standard military practice. “But I do know that most engineers and all pilots know nothing about radios and antennas. His job is definitely one of the most powerful forces keeping Ukraine’s aerial defense in good condition.”

And given the mounting evidence that both militaries and militant groups in other parts of the world are now adopting drone tactics developed in Ukraine, it’s not only his country’s fate that Flash may help to determine—but also the ways that armies wage war for years to come.

A prescient hobby

Before I can even start asking questions during our meeting in May, Flash is rummaging around in the back of the Flash-mobile, pulling out bits of gear for his own version of show-and-tell: a drone monitor with a fin-shaped antenna; a walkie-talkie labeled with a sticker from Russia’s state security service, the FSB; an approximately 1.5-meter-long foldable antenna that he says probably came from a US-made Abrams tank.

Flash has parked on a small wooded road beside the Kyiv Sea, an enormous water reservoir north of the capital. He’s wearing a khaki sweat-wicking polo shirt, combat trousers, and combat boots, with a Glock 19 pistol strapped to his hip. (“I am a threat to the enemy,” he tells me, explaining that he feels he has to watch his back.) As we talk, he moves from one side to the other, as if the electromagnetic waves that he’s studied since childhood have somehow begun to control the motion of his body.

Now 49, Flash grew up in a suburb of Kyiv in the ’80s. His father, who was a colonel in the Soviet army, recalls bringing home broken radio equipment for his preteen son to tinker with. Flash showed talent from the start. He attended an after-school radio club, and his father fixed an antenna to the roof of their apartment for him. Later, Flash began communicating with people in countries beyond the Iron Curtain. “It was like an open door to the big world for me,” he says.

Flash recalls with amusement a time when a letter from the KGB arrived at his family home, giving his father the fright of his life. His father didn’t know that his son had sent a message on a prohibited radio frequency, and someone had noticed. Following the letter, when Flash reported to the service’s office in downtown Kyiv, his teenage appearance confounded them. Boy, what are you doing here? Flash recalls an embarrassed official saying. 

Ukraine had been a hub of innovation as part of the Soviet Union. But by the time Flash graduated from military communications college in 1997, Ukraine had been independent for six years, and corruption and a lack of investment had stripped away the armed forces’ former grandeur. Flash spent just a year working in a military radio factory before he joined a private communications company developing Ukraine’s first mobile network, where he worked with technologies far more advanced than what he had used in the military. The  project was called “Flash.” 

A decade and a half later, Flash had risen through the ranks of the industry to become head of department at the progenitor to the telecommunications company Vodafone Ukraine. But boredom prompted him to leave and become an entrepreneur. His many projects included a successful e-commerce site for construction services and a popular video game called Isotopium: Chernobyl, which he and a friend based on the “really neat concept,” according to a PC Gamer review, of allowing players to control real robots (fitted with radios, of course) around a physical arena. Released in 2019, it also received positive reviews from Reuters and BBC News.

But within just a few years, an unexpected attack would hurl his country into chaos—and upend Flash’s life. 

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By early 2022, rumors were growing of a potential attack from Russia. Though he was still working on Isotopium, Flash began to organize a radio network across the northern suburbs of Kyiv in preparation. Near his home, he set up a repeater about 65 meters above ground level that could receive and then rebroadcast transmissions from all the radios in its network across a 200-square-kilometer area. Another radio amateur programmed and distributed handheld radios.

When Russian forces did invade, on February 24, they took both fiber-optic and mobile networks offline, as Flash had anticipated. The radio network became the only means of instant communications for civilians and, critically, volunteers mobilizing to fight in the region, who used it to share information about Russian troop movements. Flash fed this intel to several professional Ukrainian army units, including a unit of special reconnaissance forces. He later received an award from the head of the district’s military administration for his part in Kyiv’s defense. The head of the district council referred to Flash as “one of the most worthy people” in the region.

Within roughly a month of Russia’s incursion, Flash had created a private group called “Military Signalmen” on the encrypted messaging platform Signal, and invited civilian radio experts from his personal network to join alongside military communications specialists. “I am here to help you with technical issues,” he remembers writing to the group. “Ask me anything and I will try to find the answer for you.”

The kinds of questions that Flash and his civilian colleagues answered in the first months were often basic. Group members wanted to know how to update the firmware on their devices, reset their radios’ passwords, or set up the internal communications networks for large vehicles. Many of the people drafted as communications specialists in the Ukrainian military had little relevant experience; Flash claims that even professional soldiers lacked appropriate training and has referred to large parts of Ukraine’s military communications courses as “either nonsense or junk.” (The Korolov Zhytomyr Military Institute, where many communications specialists train, declined a request for comment.)

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He demonstrates handheld spectrum analyzers with custom Ukrainian firmware.

News of the Signal group spread by word of mouth, and it soon became a kind of 24-hour support service that communications specialists in every sector of Ukraine’s frontline force subscribed to. “Any military engineer can ask anything and receive the answer within a couple of minutes,” Flash says. “It’s a nice way to teach people very quickly.” 

As the war progressed into its second year, Military Signalmen became, to an extent, self-sustaining. Its members had learned enough to answer one another’s questions themselves. And this is where several members tell me that Flash has contributed the most value. “The most important thing is that he brought together all these communications specialists in one team,” says Oleksandr “Moto,” a technician at an EU mission in Kyiv and an expert in Motorola equipment, who has advised members of the group. (He asked to not be identified by his surname, due to security concerns.) “It became very efficient.”

Today, Flash and his partners continue to answer occasional questions that require more advanced knowledge. But over the past year, as the group demanded less of his time, Flash has begun to focus on a rapidly proliferating weapon for which his experience had prepared him almost perfectly: the drone.  

A race without end

Larger strike drones similar to the US-made Reaper have been familiar in other recent conflicts, but sophisticated air defenses have rendered them less dominant in this war. Ukraine and Russia are developing and deploying vast numbers of other types of drones—including the now-notorious “FPV,” or first-person view, drone that pilots operate by wearing goggles that stream video of its perspective. These drones, which can carry payloads large enough to destroy tanks, are cheap (costing as little as $400), easy to produce, and difficult to shoot down. They use direct radio communications to transmit video feeds, receive commands, and navigate.

MARCO CORDONE/SOPA IMAGES/SIPA USA VIA AP IMAGES

But their reliance on radio technology is a major vulnerability, because enemies can disrupt the signals that the drones emit—making them far less effective, if not inoperable. This form of electronic warfare—which most often involves emitting a more powerful signal at the same frequency as the operator’s—is called “jamming.”

Jamming, though, is an imperfect solution. Like drones, jammers themselves emit radio signals that can enable enemies to locate them. There are also effective countermeasures to bypass jammers. For example, a drone operator can use a tactic called “frequency hopping,” rapidly jumping between different frequencies to avoid a jammer’s signal. But even this method can be disrupted by algorithms that calculate the hopping patterns.

For this reason, jamming is a frequent focus of Flash’s work. In a January post on his Telegram channel, for instance, which people viewed 48,000 times, Flash explained how jammers used by some Ukrainian tanks were actually disrupting their own communications. “The cause of the problems is not direct interference with the reception range of the radio station, but very powerful signals from several [electronic warfare] antennae,” he wrote, suggesting that other tank crews experiencing the same problem might try spreading their antennas across the body of the tank. 

It is all part of an existential race in which Russia and Ukraine are constantly hunting for new methods of drone operation, drone jamming, and counter-jamming—and there’s no end in sight. In March, for example, Flash says, a frontline contact sent him photos of a Russian drone with what looks like a 10-kilometer-long spool of fiber-optic cable attached to its rear—one particularly novel method to bypass Ukrainian jammers. “It’s really crazy,” Flash says. “It looks really strange, but Russia showed us that this was possible.”

Flash’s trips to the front line make it easier for him to track developments like this. Not only does he monitor Russian drone activity from his souped-up VW, but he can study the problems that soldiers face in situ and nurture relationships with people who may later send him useful intel—or even enemy equipment they’ve seized. “The main problem is that our generals are located in Kyiv,” Flash says. “They send some messages to the military but do not understand how these military people are fighting on the front.”

Besides the advice he provides to Ukrainian troops, Flash also publishes online his own manuals for building and operating equipment that can offer protection from drones. Building their own tools can be soldiers’ best option, since Western military technology is typically expensive and domestic production is insufficient. Flash recommends buying most of the parts on AliExpress, the Chinese e-commerce platform, to reduce costs.

While all his activity suggests a close or at least cooperative relationship between Flash and Ukraine’s military, he sometimes finds himself on the outside looking in. In a post on Telegram in May, as well as during one of our meetings, Flash shared one of his greatest disappointments of the war: the military’s refusal of his proposal to create a database of all the radio frequencies used by Ukrainian forces. But when I mentioned this to an employee of a major electronic warfare company, who requested anonymity to speak about the sensitive subject, he suggested that the only reason Flash still complains about this is that the military hasn’t told him it already exists. (Given its sensitivity, MIT Technology Review was unable to independently confirm the existence of this database.) 

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This anecdote is emblematic of Flash’s frustration with a military complex that may not always want his involvement. Ukraine’s armed forces, he has told me on several occasions, make no attempt to collaborate with him in an official manner. He claims not to receive any financial support, either. “I’m trying to help,” he says. “But nobody wants to help me.”

Both Flash and Yurii Pylypenko, another radio enthusiast who helps Flash manage his Telegram channel, say military officials have accused Flash of sharing too much information about Ukraine’s operations. Flash claims to verify every member of his closed Signal groups, which he says only discuss “technical issues” in any case. But he also admits the system is not perfect and that Russians could have gained access in the past. Several of the soldiers I interviewed for this story also claimed to have entered the groups without Flash’s verification process. 

It’s ultimately difficult to determine if some senior staff in the military hold Flash at arm’s length because of his regular, often strident criticism—or whether Flash’s criticism is the result of being held at arm’s length. But it seems unlikely either side’s grievances will subside soon; Pylypenko claims that senior officers have even tried to blackmail him over his involvement in Flash’s work. “They blame my help,” he wrote to me over Telegram, “because they think Serhii is a Russian agent reposting Russian propaganda.” 

Is the world prepared?

Flash’s greatest concern now is the prospect of Russia overwhelming Ukrainian forces with the cheap FPV drones. When they first started deploying FPVs, both sides were almost exclusively targeting expensive equipment. But as production has increased, they’re now using them to target individual soldiers, too. Because of Russia’s production superiority, this poses a serious danger—both physical and psychological—to Ukrainian soldiers. “Our army will be sitting under the ground because everybody who goes above ground will be killed,” Flash says. Some reports suggest that the prevalence of FPVs is already making it difficult for soldiers to expose themselves at all on the battlefield.

To combat this threat, Flash has a grand yet straightforward idea. He wants Ukraine to build a border “wall” of jamming systems that cover a broad range of the radio spectrum all along the front line. Russia has already done this itself with expensive vehicle-based systems, but these present easy targets for Ukrainian drones, which have destroyed several of them. Flash’s idea is to use a similar strategy, albeit with smaller, cheaper systems that are easier to replace. He claims, however, that military officials have shown no interest.

Although Flash is unwilling to divulge more details about this strategy (and who exactly he pitched it to), he believes that such a wall could provide a more sustainable means of protecting Ukrainian troops. Nevertheless, it’s difficult to say how long such a defense might last. Both sides are now in the process of developing artificial-intelligence programs that allow drones to lock on to targets while still outside enemy jamming range, rendering them jammer-proof when they come within it. Flash admits he is concerned—and he doesn’t appear to have a solution.

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He’s not alone. The world is entirely unprepared for this new type of warfare, says Yaroslav Kalinin, a former Ukrainian intelligence officer and the CEO of Infozahyst, a manufacturer of equipment for electronic warfare. Kalinin recounts talking at an electronic-warfare-focused conference in Washington, DC, last December where representatives from some Western defense companies weren’t able to recognize the basic radio signals emitted by different types of drones. “Governments don’t count [drones] as a threat,” he says. “I need to run through the streets like a prophet—the end is near!”

Nevertheless, Ukraine has become, in essence, a laboratory for a new era of drone warfare—and, many argue, a new era of warfare entirely. Ukraine’s and Russia’s soldiers are its technicians. And Flash, who sometimes sleeps curled up in the back of his van while on the road, is one of its most passionate researchers. “Military developers from all over the world come to us for experience and advice,” he says. Only time will tell whether their contributions will be enough to see Ukraine through to the other side of this war. 

Charlie Metcalfe is a British journalist. He writes for magazines and newspapers, including Wired, the Guardian, and MIT Technology Review.