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Berger BE 20/2   Poste CUNZI
Spy radio set - wanted item

BE 20/2, also known as Poste Cunzi or CUNZI, was a three-piece short-wave (SW) spy radio set, developed in 1948 by Dr. Hermann Berger in Innsbruck (Austria) for use by the French Army who used it for communication with the Austrian stay-behind organisation ÖWSGV and in Indochina. 1

The radio set consists of three equally sized metal enclosures: a power supply unit (PSU), a transmitter (TX) and a receiver (RX). The units are connected together with thick red 2 cables, with the transmitter acting as the central hub.

The image on the right shows a typical Berger BE-20/2 setup with (from left to right) receiver, transmitter and PSU. The PSU is connected to the AC mains and has two voltage selectors (plugs) to set the appropriate voltage. An American field telephone handset TS-13-F 3 with Y-cable is connected to the transmitter and to the receiver.
  
Berger BE-20/2

Development of the BE-20 took place in the late 1940s. In 1948 the first prototype, the BE-20/1, was supplied to the French Army for evaluation. This resulted in an order for 100 complete sets, that were codenamed Poste CUNZI, after the name of Berger's contact person in the French Army [5]. The production version was designated BE-20/2 and was largely built from wartime (German) surplus parts, completemented by components from Berger's own factory. The 100 units were built between 1949 and 1952 [1]. The version with a German front panel is known as BE-20/3.

The sets were used a part of a nation-wide communications network for the secret underground Austrian stay-behind organisation that would have been activated in case of problems with the Soviet occupation forces. Although the French Army had ordered and payed for the 100 units, the last production batch of 10 units was never taken, probably because they had enough, or because other radio sets had meanwhile become available to them. The 10 surplus radios were left behind with the B-Gendarmerie (now: Bundesheer) 4 at the Conrad Kaserne in Innsbruck, where they were used for sending weather reports, and later (with permission) by Radio Amateurs (HAMs).

 Back to main BE-20 page

  1. French Indochina was a group of French colonial territories in South-East Asia. After WWII, several of the former colonies declared their independence and finally, following the Geneva Accord of 1954, the French evacuated and French Indochina was dissolved [4].
  2. Apart from red, some units had grey or black cables, indicating that Berger used whatever parts he could get his hands on when manufacturing these radio sets.
  3. The Berger BE-20/2 should be used with the American TS-13-F handset, which has a carbon microphone. Note that the prototype radio BE-20/1 can only be used with the TS-13-E version of the handset. More...
  4. The B-Gendarmerie was the predecessor of the Austrian Federal Army (Österreichisches Bundesheer), similar to the German post-war Bundesgrenzschutz (BGS).  Wikipedia

Complete Berger BE-20/2 set Berger BE-20/2 Front view of the complete set Front panels PSU Transmitter Receiver Handset
Controls
The diagram below shows a complete BE-20/2 (Cunzi) radio station with all cables in place. At the far right is the power supply unit (PSU) that is connected to the AC mains. It is connected to the transmitter via two thick red cables and is only activated when both cables are inserted.

Complete Berger BE-20/2 'Poste Cunzi' radio set

The radio station was intended for voice transmissions (speech) in AM, but for emergency purposes it was possible to fall back to CW and use morse code for sending messages. For this reason a fixed built-in morse key has been embedded with the transmitter. Unfortunately, there is no connection for an external morse key, which was considered a disadvantage by some users.

Parts
Mains Power Supply Unit (PSU)
PSU
Transmitter (TX)
TX
Receiver (RX)
RX
TE-13-E handset Front panel covers
Power Supply Unit   PSU
The PSU is the heaviest part of the three-piece radio set, mainly because it houses a large AC transformer with many taps, allowing it to be used on a wide variety of AC mains voltages, between 95 and 235 V. The desired voltage is selected with two plug-in power caroussels.

The PSU is connected to the transmitter via two thick red cables: one running from the PSU to the transmitter and the other one running from the transmitter to the PSU. Both cables have to be in place before the PSU is enabled.
  
PSU

Transmitter   TX
The transmitter acts as the central hub of the radio set and has three fixed wires for connection to the PSU and the receiver. The transmitter is crystal-operated and is suitable for the entire 3 - 9 MHz frequency range.

Power is supplied by the PSU via two thick red cables each with a 6-pin LIST plug at the end: one from the PSU to the transmitter, and one from the transmitter to the PSU. An external wire antenna should be connected to the socket marked A at the top left. A short orange wire distributes the antenna signal to the receiver.
  
Transmitter

Receiver   RX
The receiver has a Variable Frequency Oscillator (VFO) and can be adjusted freely over the entire 3 - 9 MHz frequency range, divided over two bands that span 3 - 5.6 MHz and 5.6 - 9 MHz respectively. It has a sensitivity of 1µV in CW (morse) and 2µV in AM (phone).

Power is supplied by the transmitter via a 6-pin LIST plug. The antenna signal is also shared with the transmitter and is supplied via an orange rubber antenna wire that is fixed to the body of the transmitter. Audio output is delevered to a 6.3 mm jack socket.
  
Receiver

Handset   TE-13-F
For speech (phone), a TS-13-F handset was used, as built by the American Microphone Company. It has a carbon microphone and was also used with some popular WWII equipment.

The handset has a Y-shaped cable with a PL55 and a PL68 plug at the ends. A butterfly-type PTT switch in present on the inside of the grip.

Note that the prototype BE-20/1 only works with the E-version of this handset, as it is the only one that has a 11315-A dynamic 1 microphone.
  
Handset

  1. The TS-13-E is also used with the BC-1000 radio and the EE-8B field phone. All other versions of the handset have a carbon microphone and are suitable for the BE-20/2 production variant.

Front panel covers
In order to protect the units agains dust and moist, some radio sets were supplied with bulged metal covers that could be fitted over the front panels. The covers could be fastened with a canvas strap.

The image on the right shows two covers, one for the PSU (Al) and one for the transmitter (E) as they were found with a surviving BE-20/2 [3].
  
Two front panel covers. Copyright Günter Hütter [3].

Interior
CUNZI is housed in three aluminium enclosures: two equally sized boxes are used for the PSU and the transmitter, whilst the receiver is housed in a somewhat smaller case. The interior of each unit can be accessed easily by removing just one screw at the rear and taking off the case shell.

In all three units, the components are mounted to the front panel so that no cables or plugs have to be removed. The set is extremely well designed and built, and should be considered very small for the era in which it was conceived.

Repairing a broken set however, is very difficult, as most components can not be accessed easily without completely dissassembling the unit. The image on the right shows the dense interior of the transmitter, with the PA valve at the bottom. In order to provide sufficient cooling, ventilation holes are present at the top of the transmitter.
  
Transmitter interior

For a more detailed description of the interior of the three units, please refer to out page about the BE-20/3, which is nearly identical.

 Interior of the BE-20/3

Restoration
Bringing an old Berger BE-20/2 CUNZI back to life may not be straightforward, as some of its components may have aged, and the thick power cables are very likely to have become brittle over time, as they consist of rubber wires. They have to be replaced before turning the radio on.

Depending on the type of cable used for inter­connection between the three units, the cable may have become stiff over time. Furthermore, as the internal wires of the cable are made of rubber, they may have decomposed completely, as illustrated in the image on the right. Such cables are beyond repair and must be replaced.

The cables of the CUNZI set featured on this page were replaced by home-made ones that consist of a red plastic tube with 6 flexible wires inside. For safety reasons, no attempt is made to use original wires, as high voltages are present.
  
Decomposed rubber wires

The result is a good looking flexible replacement cable, that will last for the next decades and that can safely be used to replace the old wiring. Note that the original mains cable may have to be replaced as well, as it is also made of rubber and will have become brittle over the years.

After the cables have been replaced it is best to first check the PSU and repair it if necessary. If the set has not been powered for several years, it might be a good idea to re-condition the capacitors by gradually increasing the mains power from approx. 50V to 220V over a period of several hours by means of a VARIAC.

Remember that the PSU will only come to life if the transmitter is connected and switch ON. If you are uncertain about the transmitter's state, install a dummy plug in socket P1 with a loop wire between pins 3 and 4, to enable the PSU.
  
Test connector for PSU - careful: HIGH VOLTAGE !

The image above shows an example of a suitable dummy plug. Note that pins 3 and 4 carry 220V AC which can be potentially lethal. Pin 6 even carries 700V DC when loop 3-4 is in place. Make sure that the pins are properly isolated and do this only if you know exactly what you are doing.

Original power cable Decomposed rubber wires Internal wiring completely broken off Restored power cables Close-up of the power connectors Cable feed-through Internal wiring Restored wiring
Connections
For connection between the three units of the BE-20/2, 6-pin LIST connectors were used from post-war Luftwaffe (Air Force) surplus stock. Sockets and plugs are available in male and female variants and a notch is present to prevent a plug from being inserted the wrong way around.

P1
This is a cable that runs from the transmitter (TX) to the power supply unit (PSU). At the TX-end it is fixed. At the PSU-end is a 6-pin male LIST plug that mates with socket P1 on the PSU. The diagram below shows the pinout of the socket P1 on the PSU, when looking into the socket.

  1. Ground (0V)
  2. 6V AC
  3. 220V ~ → to transmitter
  4. 220V ~ ← from transmitter
  5. LT +6V DC
  6. HT +650V DC
P2
P2 is a cable that runs from the PSU to the transmitter. At the PSU-end it is fixed. At the TX-end is a 6-pin female LIST plug that mates with the male P2 socket on the transmitter. The diagram below shows the pinout of male socket P2 on the transmitter when looking into the socket.

  1. ?
  2. Loop to 6 (in the plug)
  3. ?
  4. ?
  5. ?
  6. Loop to 2 (in the plug)
P3
P3 is a cable that runs from the transmitter (TX) to the receiver (RX). At the TX-end it is fixed. At the RX-end is a 6-pin female LIST plug that mates with the male P3 socket on the receiver. This cable 1 provides power to the receiver. The diagram below shows the pinout of socket P3 on the body of the receiver when looking into the socket.

  1. ?
  2. ?
  3. Linked to 1 (in the plug)
  4. ?
  5. ?
  6. ?
  1. The antenna signal is supplied by the transmitter via a separate (orange) wire with a banana-plug at the end. This plug should be inserted into the socket marked ANTENNA on the receiver.

Technical specifications
Power supply unit
  • Power
    95 - 220V AC, generator 6 - 45V, 6V or 12V DC with inverter
Receiver
  • Frequency
    3 - 5.6 MHz, 5.6 - 9 MHz
  • Sensitivity
    2µV (phone), 1µV (CW)
Transmitter
  • Modulation
    Phone (A3), Telegraphy (A1, CW)
  • Frequency
    3 - 9 MHz (crystal)
  • Output
    6 Watt (phone), 18 Watt (CW)
Known serial numbers
Originally, transmitter, receiver and PSU all had the same serial numbers, but the units often got swapped in later years. The following serial numbers have been taken from the surviving devices.

  • 0008
  • 0022
  • 0026
  • 0030
  • 0032
  • 0037
  • 0038
  • 0043
  • 0044
  • 0049
Documentation
  1. Poste CUNZI, Operator's Manual (French)
    Date unknown, but probably 1949. 59 pages.

  2. Berger BE-20/1 Power Supply Unit (PSU) circuit diagram 1
    19 July 1949.

  3. Berger BE-20/1 Transmitter (TX) circuit diagram 1
    19 July 1949.

  4. Berger BE-20/1 Receiver (RX) circuit diagram 1
    19 July 1949.
  1. Note that this circuit diagram is for the BE-20/1 prototype and does not fully match the circuit of the production units (BE-20/2). Ignore the connections of the 6-pin LIST connectors as they are wrong. Documents kindly supplied by Günter Hütter [3].

References
  1. AR ObstLt Johann Prikowitsch (OE1PQ), Auf den Spuren eines Genies...
    In the footsteps of a genious (German).
    FMTS Forum, December 1992. pp. 8-10.

  2. Heinz Binder, Berger Legende OE7HB
    Website (German). Retrieved July 2017.

  3. Günter Hütter, Berger BE-20/2 radio set
    Owner of the radio set featured on this page. June-July 2016.

  4. Wikipedia, French Indochina
    Retrieved July 2016.

  5. Waltraud Berger Coli (OE7WCT), Personal correspondence
    December 2016.
Further information
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© Crypto Museum. Created: Saturday 02 July 2016. Last changed: Friday, 23 December 2016 - 09:03 CET.
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