Buk-M2 | CHAIR BACK | SA-17 | 9S36

The 9S36 (NATO: Chair Back) is a mast-mounted fire control radar for the Buk-M2 air defense system. It is a dedicated radar-only vehicle — it carries no missiles. Its defining feature is a 21 m telescopic mast that elevates a passive phased-array antenna to detect and illuminate low-flying targets (cruise missiles, helicopters) that would be masked by terrain for ground-level radars. MAST SPECIFICATIONS Mast Height: 21 m (telescopic, hydraulic) Mast Type: Lifting-rotating telescopic Antenna: Passive phased array (Р1М2) with electronic beam scanning, in sealed container Deployment Time: 5–15 minutes (full mast raise) Redeployment: ~20 seconds (without full mast retraction) RADAR PERFORMANCE Frequency: C-band (search/control), X-band (illumination) Search Sector: ±45° azimuth, 70° elevation Track Sector: ±60° azimuth, -5° to +85° elevation Instrumented Range: 120 km Simultaneous Targets: 10 detected, 4 engaged Detection (cruise missile at 5 m alt): up to 35 km Detection (target at 20 m, RCS >0.1 m²): 17–18 km RADAR HORIZON IMPROVEMENT Target at 5 m alt: 28 km (vs 17.5 km vehicle-mounted) — 1.6x improvement Target at 10 m alt: 32 km (vs 21 km) Target at 20 m alt: 37 km (vs 27 km) OPERATIONAL CONCEPT Type B fire section: 1x 9S36 + 2x 9A316 launchers (9S36 provides illumination for both) Positioned in terrain where vehicle-mounted radar would be masked by trees, hills, buildings VEHICLE Chassis: GM-569 tracked Dimensions: 8.0 x 3.3 x 3.8 m (stowed) Engine: 710 hp Max Speed: 65 km/h Range: 500 km Crew: 4 Alternative: Wheeled semi-trailer (CHMZAP, 30 tonnes) VARIANTS 9S36: Buk-M2 (21 m mast) 9S36-1: Extended mast variant (24 m) 9S36M (Mean Back): Buk-M3 (22 m mast, 70 km detection at 5 m alt) --- Additional Data (TRADOC ODIN WEG) --- Frequency: 8–12 GHz (X, NATO Band J) Antenna Dimensions: 2.5 x 2.5 m Associated Weapon Systems: Бук-М1 (Buk-M1): 9М38 / 9M38; Бук-М2 (Buk-M2): 9М317 / 9M317 Role: Fire Control/Engagement Remarks: Buk-M1/2, digital --- From Radartutorial.eu (https://www.radartutorial.eu/19.kartei/06.missile/karte021.en.html) --- 9S36 (Cyrillic: 9С36, NATO-designator: “Chair Back”) is operating in the C band (IEEE designation) or in the H band (NATO designation) missile control radar for the medium-range anti-aircraft-missile system “Buk M1” (NATO-designator: S-27 “Grizzly”). For missile guidance, it operates as a target illumination radar in the X band (IEEE designation) or in the I band (NATO designation). The radar can also be mounted on a 2S36 telescopic mast for combating low-flying targets. The radome contains an elliptical shaped passive phased-array antenna .