A paved road on the Lithuanian border with the Russian exclave Kaliningrad gradually turns into a dirt track, and there, by the woods, is a long antenna.
This signal detection mast is part of a mobile, protected telecommunications reconnaissance vehicle operated by the German Armed Forces.
The soldiers operating it are manning NATO's eastern flank, a focal area for deterrence and defense amid heightened concerns in the region about Moscow's plans.
Kaliningrad is sandwiched between Poland and Lithuania. Historically part of Germany, it was ceded to the Soviet Union after World War II and is now the westernmost part of Russia.
German soldiers from the Reconnaissance and Effect Command are taking up position along the border as part of Vigilant Owl, a mission to capture identify and analyze signals.
"We are here to help with the surveillance and reconnaissance of NATO's eastern flank," says one of the soldiers.
The data provided by he and his colleagues goes to Lithuania and is also used ensure that Germany's military leadership is kept informed about the current situation in the Baltic states.
Life on the front line of NATO's eastern flank
That means sitting in teams of two inside armored vehicle gazing at screens and listening intently to the sounds coming through their headphones.
Outside, German and Lithuanian soldiers guard and secure the area around the clock.
The reconnaissance troops stay out in the field in small teams, largely on their own for days on end. They sleep in tents, use field toilets, drink water from canisters and eat canned food, and there are no mobile phones.
They are gathering intelligence on enemy activities in the electromagnetic spectrum, meaning all wavelengths used for communication, navigation, radar and other military and civilian purposes.
The information obtained is incorporated into a comprehensive situation report for the German and Lithuanian leadership.
Round-the-clock surveillance
Training took place for a month under real conditions as the teams detected radio signals emitted by the armies of Lithuania's two neighboring countries during the Belarusian-Russian Zapad maneuver, a large-scale, recurring strategic military exercise conducted jointly by Russia and Belarus.
Stationed near the border in several camouflaged vehicles, the German soldiers eavesdropped on Kaliningrad, with Russian military airfield in Chernyakhovsk is only about 40 kilometers away as the crow flies.
The impact of aerial bombs could even be heard and felt from a nearby training area. Troops were also deployed on the border with Belarus, a close ally of Moscow.
During that time, the soldiers decoded several hundred signals per day, forwarding them almost right away.
"We search for nuggets of gold in the background noise," says a soldier. They listen in on the enemy's radio communications and filter out usable information. "We act like a vacuum cleaner, collecting all the signals floating around, then evaluating them in a targeted manner and passing them on."
"The findings are indispensable for our reconnaissance of enemy activities and for recognizing the behavior patterns of the other side. The faster information about the enemy or the battlefield is gathered, the faster the necessary countermeasures can be taken," says Brigadier General Rainer Simon from the German Armed Forces' Cyber and Information Space Command during a visit to the position.
The soldiers divide up their work, with one operating the special equipment as the other translates the communications they hear.
Belarusian-Russian military drill 'spectacularly unspectacular'
Zapad, the military exercises showing the fighting capacity of the Russia–Belarus union, also involve strategic communication and at times testing missile systems and practicing conventional operations.
"As a rule, you have seconds to decide what is important and what is not," says the soldier, who belongs to the 911 Electronic Warfare Battalion in Germany. It is not a relaxed job, but rather time-critical and highly stressful. "It really takes it out of you," he told dpa.
The soldiers also listen closely to what is said and how it is said. Communication on the part of the Russian military during Zapad was "very professional and structured," he says.
Radio discipline was also high. Despite Western concerns about the exercise, particularly among immediate neighbors Poland, Lithuania, Latvia and Estonia, there were no surprises or unusual occurrences during the large-scale maneuver. "Zapad was spectacularly unspectacular," says Simon.
For the brigadier general, reconnaissance is more important than ever in the current geopolitical situation due to the increasing networking of all military equipment and units on the battlefield.
"The Russian armed forces make extensive use of reconnaissance and weapon systems and have large units with integrated electronic warfare capabilities, which they deploy accordingly," says Simon, also referring to Ukraine's experience as it seeks to fend off the full-scale invasion, launched by the Kremlin early in 2022.
The British Armed Forces are also working to become digitally combat-ready, says Simon. "Electronic warfare is now a decisive factor in military success."
That means drone defense, navigation protection and the use of artificial intelligence are all key, he notes.
Resilience to cyber attacks has also become more important as digital tools become ever more deeply embedded in daily life.