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Lexicon · Russia

Nebo-U

The 55Zh6U Nebo-U is a Russian long-range VHF surveillance radar designed to detect and track aircraft, missiles and low-observable targets, then pass early-warning tracks to integrated air-defense systems.

The 55Zh6U Nebo-U, NATO reporting name Tall Rack, is a Russian long-range VHF air-surveillance radar that supplies early-warning and target tracks to integrated air-defense networks.

Overview

The 55Zh6U Nebo-U is a transportable, three-coordinate surveillance radar developed for Russia's radio-technical and air-defense formations. Operating in the metre-wave VHF band, it detects and measures the range, bearing and altitude of aircraft, cruise missiles, guided weapons and some ballistic targets. It can also perform identification-friend-or-foe functions and direction-find active jammers, according to GlobalSecurity.org. It is not an engagement or missile-guidance radar; its operational value lies in warning command posts and cueing other sensors and surface-to-air missile systems.

The radar's large cross-shaped phased-array antenna provides long-range coverage and altitude measurement but requires three semi-trailers for transport. Its quoted maximum range is 600 km, while some Ukrainian reporting cites as much as 700 km against large, high-altitude targets. Effective coverage is strongly dependent on target size and altitude: published figures for a fighter-sized target fall from 400 km at 20,000 m to 65 km at 500 m, as summarized by Army Recognition.

Nebo-U forms part of Russia's layered radar network and is associated with S-300 and S-400 air defenses. Its VHF operating band is intended to improve detection of aircraft shaped to reduce their signatures against higher-frequency radars, but it does not remove the need for more precise tracking and fire-control sensors. Since 2024, Ukraine has repeatedly targeted Nebo-U stations in Russia and occupied Crimea, underscoring both the radar's importance and the vulnerability created by its size, fixed operating footprint and electromagnetic emissions.

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