In the early phase of the full-scale war in Ukraine, an FPV team’s setup was straightforward: ground station, antenna on a 10-metre mast, operator dug in within cable length. That picture is shifting. Ukrainian units, particularly along the Zaporizhzhia axis where drones have largely replaced artillery in offensive operations, have moved away from ground antennas as their primary link in many sectors. Antennas remain in service — they are still the right tool for stable lines and for engagements where their reach can be fully exploited. But airborne retransmission is now the dominant practice for fluid front lines.
What follows is a conversation with Martynas Antanaitis, Product Manager at RSI Europe, on what has actually changed on the front line, why airborne retransmission has gained ground, and what RSI’s Drone Repeater Kit (DRK) brings to the picture.
The numbers, and what conditions them
How far can an FPV team engage a target using a ground antenna in open terrain?
“Operations with an antenna in open terrain depend on a lot of compounding parameters,” Martynas says. “In our case at RSI Europe, with our antenna tested in open conditions, we reach up to 25 kilometres. But that depends on weather, humidity, and whether the terrain stays open across the full operating distance. Every object between the antenna and the drone affects signal penetration, throughput, and quality.”
He cites the much-discussed Ukrainian benchmark: “GUR has reportedly reached 33 kilometres, but again, that’s under very specific conditions.” In Lithuania, by contrast — with forested, hilly, partly urbanised terrain — realistic engagement range collapses to 3 to 5 kilometres. “The tactical problem is reconciling open terrain with operator and team safety. Truly clear ground over 20-plus kilometres, with no obstructions and no exposure, doesn’t really exist outside of test ranges.”
Range figures from the Ukrainian theatre are upper-bound numbers from favourable conditions. They describe what the equipment is capable of, not what a Lithuanian, Polish, or German unit will achieve in their own operating environments.
What terrain does to a signal
A hill between operators and target reduces effective range by roughly 20 to 80 percent. The variance is driven by what the hill is made of. Bare earth absorbs less than vegetation. Rock partially reflects, which can preserve signal strength better than a wooded slope. Trees absorb radio energy rather than reflecting it, so a forested ridge is typically worse than a stony one.
Geometry matters as much as composition. “If the hill is closer to the antenna, the signal has just left the transmitter and has no opportunity to bend around the obstacle. If the hill is closer to the target, the impact is smaller — atmospheric layering helps the signal reflect, and losses are reduced.”
Urban terrain affects performance differently — and sometimes more severely than hills. Cell towers, signal repeaters, and reflective building surfaces can interfere with drone control and video downlink. Operators report video noise, banding, and degraded line-of-sight in built-up areas — even when the geometric line-of-sight looks fine on a map.
There is also a tactical paradox built into ground-antenna doctrine. Operators want to place the antenna high and exposed for signal performance. They also want to be hidden. These two demands pull in opposite directions, and on a contested front, the second one usually wins — which means range performance lives below the equipment’s technical ceiling.
Why the shift to airborne retransmission
Martynas highlights that the front line is usually dynamic, while the antenna is fixed, and the antenna’s siting requirements conflict with operator survivability in active sectors.
“Operators look for open, elevated positions for the antenna. That restricts where the team can be. Our system has a 10-metre mast. Setting up takes time, the antenna isn’t light, and the mast itself constrains mobility — folding it up, moving it, redeploying. There have been cases where teams couldn’t relocate fast enough because of the equipment burden.”
The shift to airborne retransmission — a retransmitter antenna mounted on a carrier drone — has become the dominant practice in Ukraine. The trade-off is explicit: an airborne retransmission system requires an additional drone and an additional operator. Martynas is clear about how it weighs out: “The minuses of using a ground antenna outweigh the minuses of a drone-carried antenna. Mobility is preserved, operational security is preserved. With ground-based antennas, operator positions are chosen based on what’s good for the antenna — not what’s tactically preferable.”
There is a further point about EW. Signal margin matters beyond just reaching the target — it is the buffer that lets a drone resist enemy electronic warfare. Signal lost to terrain or obstruction is signal unavailable to push through jamming. An airborne retransmitter that maintains clean line-of-sight from altitude preserves more of that margin than a ground antenna operating through obstructed terrain.
What setup looks like, and how often it changes
A trained team with clear role separation needs 15 to 30 minutes to set up an antenna position realistically. Wind extends that, because guy lines become necessary for stability. Tear-down runs around 15 minutes if the team needs to leave fast, up to 30 if they’re packing properly.
Position changes depend on operational tempo. In active sectors with fluid front lines — Zaporizhzhia again being the canonical example — teams may move every few days. On stable lines, they can stay for months. Lithuanian exercises tend to involve more frequent changes for training purposes.
The threat picture for fixed antennas in active sectors is direct. “In the Ukrainian context, fixed antennas are actively hunted. The antenna’s position becomes a target for artillery, Grad, or KABs (gliding bombs). EW assets are hunted just as actively. The antenna is one of the most reliable signatures — its presence indicates that within a 50-metre radius there is a dug-in or fortified operator position.”
That 50-metre figure isn’t arbitrary. It corresponds to typical antenna cable length — the operators are within cable reach of the antenna they’re running.
What an airborne retransmitter changes, operationally
Moving the radio link into the air changes the operating picture in four ways.
Operator survivability. The team can sit deeper in the rear. They no longer need to be near the radiating, visually-distinctive structure that’s drawing fire. The retransmitter drone itself is a target, but it typically operates around a kilometre from the FPV team — far enough that even if it is spotted, the team’s position is not compromised, although it can still be followed to trace the operators’ position. The retransmitter operator can sit with the FPV team, up to a kilometre from the airborne unit.
Tactical position freedom. Operators can work from a low gully, a deep treeline, or a covered building. They no longer need a clearing to raise a mast. Setup time drops to roughly 5–10 minutes once the retransmitter platform is prepared. Pre-mission reconnaissance — which with antennas requires careful study of terrain, vegetation, and obstacle lines along the working azimuth — becomes lighter, because the retransmitter can be repositioned in flight.
Range and line-of-sight in obstructed terrain. A hill no longer ends the engagement. If the obstacle is 50 metres tall, the retransmitter climbs to 55 and the line-of-sight problem disappears. With antennas, the same problem requires either a different position or a taller mast — both of which carry their own constraints.
EW resilience. With clean line-of-sight from altitude, more of the link’s signal budget remains available against jamming.
There is, however, a real cost in using a drone for retransmission, and Martynas does not minimise it. An additional drone — often a modified FPV with a stabiliser, or a commercial platform such as a DJI Mavic 3, or for heavier payloads a DJI Matrice, Autel, Parrot, or Skydio. An additional operator. An additional point of failure: if the retransmitter goes down, the FPV team is immobilised until a backup is in the air. Tight coordination requirements between the retransmitter pilot and the FPV pilot. Mission duration is constrained not only by the FPV’s battery, but also by the carrier drone’s.
There is also a doctrinal nuance. Standard practice is to launch the retransmitter first, then the FPV. But in higher-risk situations — where the retransmitter’s hover signature might attract a reconnaissance drone or mission duration is critical — teams reverse the order to minimise the retransmitter’s time in the air. Hovering retransmitters are actively hunted. Martynas references a video circulating among operators of a fibre-optic FPV attacking a DJI Matrice carrying a retransmission module.
How much it changes performance
Telegram channels run by Ukrainian drone practitioners cite airborne retransmission as making FPV operations 3 to 5 times more effective than ground antennas in obstructed terrain. Forbes has reported a roughly 2x improvement. Both figures are anecdotal — not from a controlled study — but directionally consistent with what operators describe.
The change in mission planning is harder to dispute. Antenna-based planning is bounded by the antenna’s reach and the line-of-sight envelope. Retransmitter-based planning is bounded by the carrier drone’s battery endurance — typically up to 20 minutes of hover for smaller Mavic-class platforms. The constraint shifts from “can we reach the target” to “how long can we stay overhead.”
In open terrain with clean line-of-sight, the two systems converge in performance — the antenna’s range is fully usable, and the airborne retransmitter’s main contribution becomes operator security rather than reach.
What RSI Europe built into the DRK
The DRK — Drone Repeater Kit — with two main components, the Mini Antenna Rack (MAR) and a Repeater Unit (RTK) is RSI Europe’s answer to this problem set. It is not a clean-sheet design but the product of iteration on Ukrainian operator feedback. A few features stand out as direct responses to known field requirements.
Integrated control PCB with status indicators. The RTK runs on a custom PCB with its own microcontroller managing the pairing of control and video transmitters and receivers. LED indicators confirm link status across each leg of the chain — operator-to-retransmitter, retransmitter-to-drone. Pairing is reduced to single-button operations on the housing. The result is faster pre-flight and faster troubleshooting when teams have minutes to be airborne.
The Mini Antenna Rack (MAR). The MAR is an IP67-certified, small suitcase-form-factor mountable unit with a 20-metre cable. It can sit outside, in rain, in a dugout, on a vehicle — unattended, without disassembly between missions. It only opens when downlink frequencies need to be changed. Operators run the cable back to a concealed position. The MAR needs direct line-of-sight to the RTK; the operators do not.
Martynas frames the MAR as a direct response to feedback: “The Ukrainian operators told us they didn’t want to disassemble equipment between missions. They wanted operation from the transport case, in a ready state. The MAR delivers that.”
Cross-compatibility. The DRK is universal. The transmitters can be tuned to operate with non-Shpak drones. The antenna is RSI-built and covers a wide frequency range, which extends compatibility to other manufacturers.
Field-serviceable assembly. Disassembly and reassembly takes about 5 minutes with no additional tools. The antenna unit weighs around 800 grams, mountable via Velcro or 3D-printed adapters supplied with the kit. Power runs on a custom battery frame with its own charger, but the system also accepts standard XT60 connections — meaning a team can plug in available batteries if their primaries are dead. One battery delivers up to an hour of operation, enough for 3–4 sorties; the kit ships with three.
A next iteration with antenna angle adjustment — useful for maintaining the link as the carrier drone changes altitude — is in development.
The strategic point
The choice for European militaries planning around drone integration is not between ground antennas and airborne retransmission. Both have a place. The question is whether the system being procured today reflects what has been learned in three years of high-intensity drone operations — about operator survivability, about position selection, about terrain in active sectors. The DRK is built around those lessons.