The 40V6M/MD family of mobile mast systems is a ubiquitous feature of the Russian air defence landscape, used with more different radar types than any other design. The 40V6M/MD has no known equivalents in the West, and represents a uniquely Soviet approach to standardising the deployment of radar equipment. While the headlong drive to high mobility shoot-and-scoot radar and missile systems has seen the 40V6M/MD decline in popularity with many clients, this mast design remains on offer in catalogues and brochures for most of the latest Russian radar designs, be they with mechanically steered antennas or phased arrays.

The first known application of the 40V6M series was as part of the early S-300PT / SA-10 Grumble A semi-mobile Surface to Air Missile system, employed to elevate the 5N63 Flap Lid engagement radar, the 36D6/ST-68U/UM Tin Shield acquisition radar, and the 5N66/5N66M Clam Shell FMCW low altitude acquisition radar.

The stated motives behind the development and deployment of the 40V6M/MD masts were to provide acceptable low altitude coverage footprint for the S-300PT system, tasked with intercepting low flying nuclear armed Strategic Air Command B-52G/H, FB-111A bombers, and the AGM-86B ACLM and MGM-109G GLCM cruise missiles, all of which were considered terminal threats to the Rodina. The severity of the threat justified the considerable expense in developing a complex high payload mast system, suitable for deployment in often complex terrain, and in often highly adverse climatic and weather conditions.

A particular problem the Soviets faced during this period was the diverse geography of the Soviet Union and its Warsaw Pact client states. Terrain varied widely, from flat central Asian steppes, tundra and taiga, to hilly and often mountainous terrain in European Russia, Central Europe, the Caucasus, the Urals, and the foothills of the Himalayas. Where elevated terrain was available, sites for placing S-300PT battery radars would be abundant. Many areas of European Russia and Siberia are heavily forested with tall conifer and deciduous trees, presenting an additional problem with achieving good antenna elevation above terrain and foliage.

Physics mostly do not favour low altitude radar propagation. The curvature of the earth is a primary consideration, as it limits geometrical line of sight to targets. Refraction, the byproduct of decreasing atmospheric density with increasing altitude, favours propagation by "bending" the ray path over horizon, but this effect only becomes significant at tens of nautical miles of range to a target, or greater.

Elevating a radar antenna by using a mast will directly increase the useful range against a low altitude target. It also aids in detection of high flying targets at much longer ranges, by reducing the necessary depression angle of the antenna boresight required to see such targets.

Development of 40V6 family of masts started during the 1970s, with the design entering production around 1980. The design and manufacture was performed by the  NKMZ (Novokramatorsky Mashinostroitelny Zavod - http://www.nkmz.com/) in the Ukraine, best known for the design and manufacture of space launch vehicle gantries and associated support equipment. Key design personnel were given in 1985 Soviet government awards for their technical achievement on the 40V6 project.

A key design imperative was stability of the design under high wind loading and near miss nuclear attacks. Ukrainian sources claim that a simulated nuclear blast overpressure wave failed to topple the 40V6M, only causing one of the outriggers to lift off the ground, with the mast returning to its stable position.

No summary figures for the total number of 40V6M/MD systems built have ever been disclosed, but a number in the hundreds is supportable, as one or more masts were deployed with each S-300PT battery, and the mast was also supplied with standalone Tin Shield and Clam Shell installations.

In 2004, following the breakdown in relations between Russia and the Ukraine, NKMZ ceased manufacturing products for the Russian military-industrial complex. As the 40V6M/MD remains on offer as part of Russian supplied radar and SAM system packages, including new build S-300PMU2 Favorit and S-400 systems, it is likely that warehoused units and/or refurbished former Russian stocks are being supplied, although production of new hardware in Russia cannot be ruled out. Recent Russian publications on military tow tractors cite two more variants of the design, the 40V6M-R and 40V6M-R0, but no open source details of these designs have been published as yet.


ST-68UM Tin Shield acquisition radars deployed on a 40V6M mast. Above: This uncommon perspective of the system is revealing, insofar as it shows the use of the mast to position the radar phase centre above the treetops, in typical Russian rural forested terrain. The image also shows clearly the splayed out outriggers, the Tin Shield equipment van, and the MAZ-537 tractor. Below: another Tin Shield in forested terrain (Russian Internet images).

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40V6M/MD Tow Tractors

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40V6M mast system stowed during road transit, towed by the legacy MAZ-537 tractor. The design has excellent road mobility but the 1-2 hr deployment and stow time does not qualify it as a 'shoot and scoot' system. Below the MAZ-537, which despite its age still remains widely used. It was designed as a heavy artillery tow tractor but later used to tow ballistic missile transporters and other large payloads.

A 40V6M mast system being transported by flatbed rail car (Russian internet image).

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40V6M Mast Deployment

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Erecting the extended height 40V6MD mast arrangement requires the use of an 80 tonne crane, the KT-80 on a MAZ-7916 is most often used for this purpose - the vehicle is based on the RSD-10/SS-20 IRBM TEL. The 40V6MD requires three semitrailers for movement.



A derelict 40V6M mast system in stowed configuration, above tow tractor end, below antenna head end. Note the cable ducting leading up the mast to the antenna head (Russian internet images).

In February, 2010, Michael Jerdev visited the Elektrostal' base outside Moscow, home to the 3rd Surface to Air Missile Battalion of  PVO Unit 61996, equipped with early variants of the S-400 SAM system. At least two examples of the 40V6MD are hosted at this base, and detailed imagery of one partially deployed 40V6MD mast system, the example in excellent condition, was collected.

Detail of upper mast segment of partially deployed 40V6MD.

Detail of stowed lower mast segment of partially deployed 40V6MD.

Detail of stowed lower mast segment hydraulic actuators.

Above, below: detail of segment join hinge and rigid A-frame. The latter is used to maintain alignment of the upper segment, and the lower segment is lifted from horizontal to vertical position.

The LEMZ 5N66 Clam Shell 2D FMCW acquisition radar deployed on the 127 ft 40V6MD extended height elevating mast (Russian Internet).

LEMZ 5N66/5N66M/76N6E Clam Shell FMCW Acquisition Radar

An excellent study of the 5N66M Clam Shell B antenna system by Said Aminov, produced at Togliati in Russia (© 2009, Said Aminov).

30N6 / 40V6M Flap Lid A - the 40V6M and 40V6MD masts are most frequently used with the 76N6 and 30N6 series radars, usually paired with equal height masts. The 40V6M and 40V6MD masts remain a cited option for the S-400 system's 92N2E Grave Stone and 96L6 Cheese Board radars (© 2009, Said Aminov).



Detail of the 5N63 Flap Lid A  F1 radar head module deployed on 40V6M semi-mobile mast system, by Said Aminov, produced at the Togliati Museum in Russia. The dual plane monopulse circular polarised primary feed has been stripped and the concertina shroud has deteriorated. The operator consoles are in the F2 module, typically located on a truck. Later self-propelled 5N63S Flap Lid B variants retained the capability to deploy the F1S module on the 40V6M/MD mast, with the F2S module remaining attached to the MAZ-7910 8x8 vehicle chassis (© 2009, Said Aminov).