The Wollenberg Bunker – Linking East Germany and the USSR

Heading to Berlin or the former GDR? Looking for traces of the Cold War open for a visit?

A Travel Guide to COLD WAR SITES in EAST GERMANY

Second Edition - 2024

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The events taking place on the geopolitical stage during the last decade of the Cold War – the 1980s – gave little indication of the imminent collapse of the Soviet-led Eastern Bloc (1989-1991). Correspondingly, looking at the amount of technology developed and deployed in the military field during the late, hi-tech stage of the Cold War, it is easy to notice that opponents on both sides of the Iron Curtain dedicated a significant (and even increasing) budget in preparation for a possible total confrontation. Reading papers and specialized books from the time, the outbreak of an open conflict, such to put a violent and abrupt end to years of opposition between the two opposing systems by recurring to nuclear warfare over the territories of Western Europe (most of them belonging to the NATO alliance, and all being substantially more militarized than today), was not deemed just likely, but more as a matter of time.

The БАРС system – The tropospheric network of the Warsaw Pact

In that era of extreme tension, it is not surprising that one of the most sophisticated and expensive assets developed and deployed jointly by all Nations in the Warsaw Pact, of course led by the USSR, came alive. History would cut its life short though, and as soon as the Warsaw Pact disintegrated, as a result of the opt-out from communist dictatorship of all Countries in Eastern Europe, this asset was decommissioned. This system was the tropospheric communication system ‘БАРС’, a Russian word reading ‘BARS’ and meaning ‘snow leopard’. The name stands as an acronym for four words in Russian, which translate into something like ‘Sheltered autonomous radio communication system’.

The idea put forward by the Soviet top-ranking military staff in the early 1980s (prior to the onset of Gorbachev administration) was that of a system capable of transmitting complex orders (not just simple signals, like for opening a bunker door or silo, but articulated messages) in a safe encrypted way, at a long distance and minimizing the chance of a complete breakdown even in case of an enemy nuclear attack. Despite being not new, the concept of a resilient and reliable system, such to allow exchanging significant amount of data without relying on cables, had been tested in earlier stages of the Cold War only for short-radius operations. Mobile transmitters/receivers, loaded on purpose-designed trucks, allowed for a reduction of the risk of a direct hit from an attacker, and for a quick redeployment in case of need. However, for the amount of data and range required for the coordination of a war scenario, involving many different Countries, and geographically encompassing an entire continent, a different system was required, capable of transmitting more massive data flows on longer distances, with a reduced risk of a sudden or complete interruption.

The БАРС system was based on a certain number of stations, scattered over the territory of the Countries of the Warsaw Pact. Each node was built as a bunkerized, manned military installation, featuring high-power, high-frequency fixed antennas emerging from the ground, and an underground shelter protecting all the technical gear required for manipulating the data to be sent or received, interfacing with the other existing local (i.e. national) networks for military and executive governmental communication, and of course managing the tremendous amount of energy required to pump a long-reaching signal into the ether.

Laying on the front line with the West, hosting a Soviet contingent of some hundred thousands troops (see here and links therein), aircraft (see here), missiles (see here) and nuclear warheads (see here), and being a key-ally of the USSR in case of the outbreak of an open war (at least until late 1989), the German Democratic Republic (or GDR, or DDR in German) was clearly included in the БАРС network from the initial drafting phase. Similarly, Poland, Czechoslovakia, Hungary and Bulgaria, and of course the Soviet Union (which included Belarus and the Baltics, and stretched west to Kaliningrad), all had БАРС stations on their territory. Stations were located at a range of a few hundred miles from one another, thus within the range required for each of them to communicate with one or more of the other nodes. Data (e.g. orders, reports or authorizations) input locally could be relayed along the network through intermediate nodes, down to the intended destination node. There were 26 nodes in total, of which four were in the USSR.

The Wollenberg site – Bunker 301 ‘Tushurka’

The GDR in particular had three stations built, all along the border with Poland, and located east of Berlin – namely Station 301 in Wollenberg, at the same latitude of Berlin, Station 302 in Langsdorf, towards the Baltic coast, and Station 303 in Röhrsdorf (near Königsbruck), not far from Dresden in the southeast of the GDR territory. The first among them, the Wollenberg site (codenamed ‘Tushurka’) could communicate with the other two national stations, as well as with Station 207 in Poland, from where data would be transmitted further down the network, towards the USSR.

The site was built by the GDR state, with technical hardware coming from several Countries within the Warsaw Pact, and most of the military hi-tech components manufactured in the USSR. The actual site (similar to its sister sites) was built in the frame of a highly secretive operation. The staff comprised about 60-70 men, the majority of which were military, where about 15% were civil technicians. Maximum security clearance was required, due to the top-secret nature of the installation and of the overall БАРС system. The bunkerized part of the installation was only a component of the larger premises of the base, camouflaged within the trees on the side of low-rising hill.

As pointed out, the immense spending required for setting up this multi-national hi-tech military communication system, which was extensively tested and completely commissioned (as a network) by 1987, did not save it from a quick demise and disappearance. In particular, Station 301 went definitively offline as early as August 1990.

However, the fate of the Wollenberg site was not so sad as that of many former Soviet or NVA (i.e. the East German Army) installations in the GDR. The high-power antennas were torn down, but except from that, little material damage was inflicted to the buildings and bunker on site. The place was basically shut-off and left dormant, until when a society of technically very competent local enthusiasts started a plan to preserve and open it to visitors, as a memorial specimen of the technology of the Cold War years.

A visit to the Wollenberg bunker site reveals a tremendous deal of interesting details, very uncommon to find elsewhere in the panorama of Cold War relics around Europe. Thanks to a careful preservation and restoration work, the bunker has most of its original systems still plugged to the grid and lit-up – some of them are reportedly still working! Even though the communication networks have been severed, the experience in the bunker is really evoking, and the atmosphere – with all the lit-up cabinets, lights, CCTV cameras, 1980-style screens, etc. – closely resembles that of the bygone era when БАРС was operative!

This report and photographs were taken during a private visit to the bunker, carried out in the Summer of 2023.

Sights

A visit to the the installation in Wollenberg starts from the original high-security access gate. As you may quickly notice when passing through it and getting a first view of the site, the state of preservation is exceptional. Except for the lack of military staff around, everything looks mostly like in the years of operation.

A group of soft-construction service buildings and a reinforced multi-entry garage constitute the first – and visible – nucleus of the installation. All buildings are painted in a camo coat.

A former building for the on-site staff has been turned into a permanent exhibition, with memorabilia items from the Cold War years, when the Nationale Volksarmee (or NVA, the Armed forces of the GDR) cooperated with the Soviet Red Army and the national Armed forces of other Countries in the Warsaw Pact.

A meeting room, now employed also for small gatherings, is especially rich of interesting and diverse items, including emblems, books, memorial plates and pennants, as well as TV screens, hi-fi systems and and beamers from the era.

Another room has been set-up as a control center for the base, with an original console and regional maps.

Compared to military bases (for aircraft or tanks), the Wollenberg installation is rather compact, with a main road giving access to most of the (not many) buildings on site, as well as the bunker. Actually, the bunkerized part was built under a low-rising hill, with the antennas originally standing on top of it. Access to the bunker is possible either by climbing uphill on the main road, or through a suggestive original pedestrian tunnel. The latter starts from within the service building itself, and – somewhat unexpectedly, for an underground installation – it climbs uphill, while keeping beneath the surface of the hill side slope. The lower end is guarded by an original CCTV camera.

At the top end of the tunnel you can find the actual access to the bunker. The design and reinforcement level conferred grade ‘D’ protection according to the military standard in use at the time, with grade ‘A’ being the strongest. Access is through an airlock, constituted by two tight doors at the opposite ends of a small vestibule built in concrete. This design allowed protection from the blast of a nuclear device.

Notably, the locking mechanism of the tight doors is Soviet military standard, which can be found in high-value installations like nuclear depots elsewhere in the Eastern Bloc (see for instance here in Poland, and here in Czechoslovakia).

To the visitor with some experience of Cold War installations, it will be apparent from the very start of the tour that the state of conservation of the bunker, including the systems in it, is exceptional, similar to the rest of the Wollenberg site. The original warning lights and the CC-TV camera for identifying people at the entrance are still in place.

Next to the entrance, a control room with technical gear for checking-in can be found – including original dosimeters for radiation and chemicals, mostly Soviet-made. Looking inside these devices is possible, and reveals a great deal of sophistication in the design and realization of the military-grade material from the time.

Showers and sinks for washing, as well as canister for disposing of contaminated clothes, are located in the same area.

Upon getting access to the sealed area of the bunker and passing by the decontamination facility, you find yourself on the top floor of the underground bunker. The high-technology gear required for the transmission/reception of data on the БАРС network, as well as the interface with other national communication systems, required for receiving data, issuing orders, etc. over the territory of the GDR, were located on this floor.

Two symmetrically placed rooms host two twin transmission centers for the БАРС system. A single manned console can be found in each of them, surrounded by electronic cabinets and switches. At a closer look, all the material herein is Soviet made, and labeled in Russian only.

On the wall ahead of the console station is a set of cables, communicating with the antenna and allowing to set the orientation and monitoring its status.

The actual signals transmitted to the antenna, or received from it, traveled along special hollow ducts, with an almost rectangular section. Bundles of these ducts can be found in the ‘Sender’ (which means ‘transmitter’ in English) room, immediately next to the room where the manned console is.

The modulation and demodulation of the signals going out and coming in respectively through the antenna on top of the bunker required some special pieces of electronics, which included the Soviet-designed KY-374 klystron (codenamed ‘Viola’), a component to be found in the cabinets of the ‘Sender’ room.

Following the hollow ducts, it is possible to find where they finally exit the usually manned part of the bunker, bending into receptacles and leading outside. Piping related to other systems, including air conditioning, can be seen as well crossing or running in the same narrow technical corridors.

Beside the consoles monitoring the antenna and the data flowing through it, a kind of operative room for communication can be found, where consoles allowing to receive and forward data and communication to/from all systems are on display. This largely original room features consoles of different levels of technology.

Original explanatory schemes showing the basic features of the БАРС system are on display in that area – in Russian!

An adjoining room features the cabinets required for making all these system work. The cabinets are really many, with a significant share of material manufactured in the USSR. The sight of all these cabinets together is really impressive, and tangibly provides the feeling of a high technology, sophisticated and expensive design. It compares well, but in a largely up-scaled fashion, to the electronics to be found in some special communication bunkers on the western side of the Iron Curtain (see here).

Interspersed with the original arrangement of the cabinets and consoles are some displays of original material. These include specimens of different types of cables for signal transmission – some of them hollow and pressurized, others featuring impressive bundles of thinner wires – the KY-374 klystron, and other once top-secret core components of the БАРС transmission system. Also on display is one of the few remaining parts of the original system of antennas, once on top of the bunker. The antennas were the only part to be physically torn down when the system was decommissioned, upon the demise of the Warsaw Pact and the end of the Cold War.

The bunker was manned by military and technical staff 24/7. Furthermore, as typical for bunkers from the Cold War era, provision was made at a design level to allow the staff to live isolated within the bunker for an extended period of time, in view of the eventuality to face a nuclear fallout scenario.

On the same floor as the technical rooms, the commander of the station had his own private room. This is still adorned with typical Soviet iconography, as well as everyday material from the age when the bunker was operative.

A small canteen, with a kitchen and a modest living room, can be found at the same level. An original storage room has been employed to gather examples of everyday products, like soap, skin care cream, etc., as well as canned food, cocoa, and beverages of all sorts.

This represents a very rich catalog of now largely defunct and forgotten labels, from the age and regions of the Eastern Bloc (and especially from within the GDR). Also on display are bottles of spirits, likely still very good!

The visit proceeds then to the lower floor, which can be reached through a flight of metal stairs.

The lower floor host the plants required for the regular operation of the entire bunker, such to guarantee operational ability even in case of an enemy attack carried out with nuclear, chemical or biological warfare. The air filtering and conditioning system is very modern. Beside typical filtering drums for particles, to be found also in other bunkers (see for instance Podborsko here), you can see a bulky filtering and climate conditioning system, neatly arranged within two parallel square-shaped ducts. Filtering against chemicals as well as biologic agents was carried out employing special active filters.

Sensors for the level of contamination of the bunker air can be found in different rooms. Much material here is standard Soviet-made.

Systems for water pumping and compressed air can be found as well, including compressors, pumps and reservoirs. Looking at the always interesting factory labels in this area, it is easy to find export products of Bulgaria, Romania and other communist dictatorships of the era. Of course, much hardware is also manufactured in the GDR.

Electricity was supplied from the outside grid, yet capability for self-sustaining in case of a grid loss (for instance in case of war) was implemented as well. Three big German-made Diesel generators have been put in place, and are still in an apparently good condition.

Another example of the high technological standard reached in the late Cold War era is represented by the control room for the plants within the bunker. A manned control station, with a console and a direct view of lit-up cabinets, reporting the status of the various systems running in the bunker, compares well with control rooms of large industrial plants in operation today.

Carefully kept in its original status, with many of the electric links and cabinets still working, the sight of this room is especially evoking.

Also on the lower floor are the sleeping rooms for off-duty staff. Typically, this was not employed except for drills, when the bunker could be sealed to simulate operations in case of the outbreak of hostilities.

Back to the upper floor, it is possible to exit the bunker via a stairway and through a side gate. You will find yourself on top of the low-rise hill where the bunker has been dug. Here the concrete base of the crane where the БАРС antenna used to sit are still visible. Notably, these antennas were much smaller than the tropospheric antennas employed for the TROPOSCATTER system of NATO. This was the result of a different bandwidth employed for transmissions. Therefore, even in the days of operation, the antennas on top of the bunker were not as sizable as those of TROPOSCATTER installations (which were enormous in size).

Looking closely, in the top area of the installation, the duct for supplying the Diesel oil tank of the bunker can be found, similar to sensors for radiation and other atmospheric parameters (similar to what can be found also in other nuclear-proof bases, for instance here). These allowed to monitor the conditions of the outside air, detect an attack and trigger or manage the sealing of the bunker in case of need, by locking all the tight doors.

This access to the bunker is fenced by the original electrified fence, severing this area from the rest of the installation through a further layer of security.

All in all, a visit to the Wollenberg bunker offers an incredible insight in a fascinating and crucial field of warfare – data and communication exchange – as well as a lively and evocative display of a late Cold War hi-tech installation from the Soviet side of the Iron Curtain!

Getting there & Visiting

The German name of the Wollenberg bunker is ‘Militärhistorisches Sonderobjekt 301 Wollenberg’. It can be reached very easily with a car. It can be found in the open countryside along the regional road 158, driving about 35 miles (about 1 hour) northeast from downtown Berlin towards Poland. The exact location is between the small village of Höhenland (~4 miles) and the more sizable Bad Freienwalde (~6 miles). There is a large parking area immediately next to the road, giving direct pedestrian access to the premises of the former military installation. Despite being placed very conveniently, the site is rather elusive when passing by, since it is hidden in the trees and not directly visible from the road. The address corresponding to the place in Google Maps is Sternkrug 4, 16259 Höhenland. The inconspicuous village of Wollenberg, giving the name to the installation, is just nearby, but it is not crossed by the regional road, and it should not be employed for pointing this destination with a nav.

The Wollenberg bunker is a listed historical installation. It is perfectly maintained, privately managed, and it can be regularly accessed with guided tours. These are offered typically one day per week in the summer, or by prior arrangement. Possibly the best option for getting the most out of your visit is getting in contact with the group of very knowledgeable enthusiasts running the place. The official website is here (do not be discouraged by the ‘static’ appearance of the website, they are very active, and they shall typically answer your inquire).

My visit was planned by initiative of Dr. Reiner Helling (see also here), and we visited in a group of three, including the guide (Dr. Michael Schoeneck, a former engineer, with a profound knowledge of any technical aspects related to this installation), which happened to be a perfect option for touring also the narrowest receptacles of the bunker. Visiting in groups too big may be not advisable, since the rooms and corridors are rather narrow, and the place may turn overcrowded for interacting with the guide and for taking good pictures. I think the visit – including the technical content – may be tailored to the needs of the audience. For technical-minded subjects, historians and former military, a visit may take about 2-3 hours (the latter was my experience). In my case, the guide could understand but not speak fluent English, yet Dr. Helling could translate with ease all the explanations. Of course, if you have at least a basic knowledge of German and of the technical material you are looking at, this may simplify your visit, which is in any case highly advisable for those interested in military technology and the Cold War.

Heading to Berlin or the former GDR? Looking for traces of the Cold War open for a visit?

A Travel Guide to COLD WAR SITES in EAST GERMANY

Second Edition - 2024

DON'T LEAVE IT AT HOME! AVAILABLE in PAPERBACK or KINDLE from your national Amazon store!
amazon.com | amazon.de | amazon.co.uk
amazon.it | amazon.fr | amazon.co.jp