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Germany France Cold War Telefunken ESK-632 → ← B2M
German/French spy radio set
The ESK-52 was a spy radio station, developed by
Telefunken
in Hannover (Germany) in 1952 for clandestine operations by the French
intelligence services. The radio was based on the similar Type 41,
which was built for the German intelligence service, the
Bundesnachrichtendienst (BND).
Like the Type 41, it is actually a post-war replica of the
British Type 3 Mk II (B2) spy radio set.
For security reasons the ESK-52 was officially described
in the documentation as Amateur Radio Set.
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The radio set is housed inside a large cardboard suitcase and
consists of three units, just like the British B2: a
power supply unit (PSU)
at the right, a receiver (RX)
at the front, and a transmitter (TX) at the back.
A leather strap at the center keeps the set in place when travelling around.
At the far right is a large storage compartment in which the
acessories,
such as the morse key,
the headphones, the power cables, the antenna
and spare valves were kept. The documentation (operators manual,
frequency tables, etc.) were stored
behind a panel in the top lid
of the case.
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The ESK-52 shown here has a control panel that is labelled in French. It was
used for many years during the Cold War
by the French intelligence service.
Although the radio officially had to be destroyed once it was
decommissioned, it has miraculously escaped demolition.
It is currently unknown how many ESK-52 sets were produced, but given
the low serial number of our set (0059) it is likely that no more than
100 sets were produced. Today they are a very rare find.
A few years after the launch of the ESK-52, in 1954,
Telefunken introduced the ESK-632 which was an improved version of
the ESK-52. A modulation amplifier was added to the transmitter
and a socket for a microphone was added to the front panel.
It was also listed as Amateur Radio Set.
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Shortly after WWII, in 1950,
Telefunken
in Hannover (Germany)
started building spy radio sets that were 'inspired' by
the British WWII Type 3 Mark II (B2).
The first radio set that was produced by the HOGA 1 business unit
at Telefunken was the B2M,
which was actually a 'chinese' copy of the British B2.
The front panel layout and the circuit diagram were nearly identical
and the only real difference was the use of 'rimlock' type valves in
the oscillator circuits of the German B2M [1]. Unlike the original
B2, the B2M consisted of three units in a single
metal enclosure.
➤ More about the B2M
In 1952, the ESK-52
and the Type 41 were introduced at the successors
to the B2M.
The design is based on the B2M, but contains a number of
improvements, such as the absence of plug-in coils in the transmitter
section. Although the ESK-52 consists of 3 units (RX, TX and PSU),
they are mounted together in a single frame
(and wired internally) that is built inside the suitcase.
As the transmitter of the ESK-52 can only be used for CW (morse),
an improved version, known as the ESK-632
was released in 1954. A modulation amplifier was added to the transmitter,
allowing the connection of a crystal microphone in order to produce
Amplitude Modulation (AM).
➤ More about the ESK-632
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At the time, the HOGA business unit of Telefunken Werk-Hannover,
was responsible for the production of the ESK-52 radio set and the
earlier B2M. It is currently unknown what the abbreviation 'HOGA'
stands for. If you have further information, please let us know.
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The transmitter (TX) is built around two valves (tubes):
a 6AG7 for the crystal-based oscillator (CO) and a 6L6 for the RF
power amplifier (PA). It covers a frequency range of 3 to 16 MHz
and produces an output power of 20W.
The transmitter is suitable for CW only.
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The superheterodyne receiver is built around four valves:
2 x ECH42 and 2 x EAF42. It has the same frequency span as the
transmitter (3 to 16 MHz), divided over three ranges
(3-5.5, 5.5-7 and 7-16 MHz). The IF frequency is at 470 kHz.
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The Power Supply Unit (PSU) is mounted to the right of the transmitter
and receiver and is internally wired to the other two units.
It is suitable for a wide range of AC mains voltages (90 - 230V),
but can also be operated by a 6V DC battery. In the latter case
an electromechanical vibrator is used to convert the 6V DC into
the LT and HT voltages needed by the set.
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The ESK-52 was usually supplied with a good quality morse key
such as the bakelite Wehrmacht key shown here, which was actually
a leftover from WWII. Note the special connector with the narrow
pitch that is used for connection to the transmitter.
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The ESK-52 is suitable for connection of any high-impedance
pair of headphones. It was commonly supplied with the Telefunken
headphones shown here, which was actually a leftover from WWII.
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The suitcase has a large storage compartment to the right of the radio
set, in which all accessories, such as the morse key, the headphones and
the antenna wires are kept.
Also in this compartment are the spare values, fuses, a mains lamp
adapter, etc.
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The ESK-52 was supplied with typed instruction in French.
For service personnel, there was also a technical manual with circuit
descriptions and circuit diagrams. In the latter manual, the radio was
identified as 'Amateur Radio Set' in order to hide its true purpose.
The documents were usually stored inside the
rear compartment,
inside the top lid of the suitcase.
➤ Short form instructions
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In an operational context, the ESK-52 was supplied with a frequency table
that was used by the operator to determine which channel to use on certain
days and times. The image on the right shows an original frequency table that
was found with the radio set featured here.
Several blank frequency tables were provided for 'future' use by the operator.
The tables were supplied in a transparent plastic 1 sleeve.
➤ Original frequency table
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The plastic sheet has been removed from the tables shown here, as it
contains acetate which produces toxic fumes that can potentially damage
the documents.
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Device Suitcase spy rado set Purpose Agent communication Model ESK-52, Type 41 Year 1952 Manufacturer Telefunken, Hannover (Germany) User French intelligence, French stay behind Predecessor B2M Successor ESK-632 Mains 85 - 234 V AC, 40-60 Hz Battery 6V DC Vibrator NSF 32 - 2 NT 6 Parts 3 (transmitter, receiver, PSU) Dimensions 585 × 350 × 170 mm (suitcase)
430 × 320 × 150 mm (bare radio set)
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Frequency 1.4 - 9 MHz (1.4 - 4.5 MHz with doubler) Output 20W (15W when battery powered) Modulation CW Impedance 600 - 1000 Ω Valves 6AG7, 6L6G
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Frequency 1.4 - 9 MHz Bands 3 (1: 1.6-3 MHz, 2: 3-5.5 MHz, 3: 5.5-9 MHz) Modulation CW, AM Sensitivity < 1µV (A1, without filter)
< 2µV (A1, with filter)
< 5µV (A3) Valves 2 × ECH42, 2× ECF42
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- Antenna wire (20 m)
- Ground wire (10 m)
- 2 × Isolator
- Ground pin
- Morse key
- Headphones
- Battery power cable
- Mains power cable
- E10 light fitting adapter
- Spare fuses
- Spare valves (tubes)
- Operating instructions
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Poor quality copy.
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The extra circuit (AM voice modulator) of the ESK-632
is embedded within this manual (page 23-26).
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© Crypto Museum. Created: Sunday 05 February 2017. Last changed: Friday, 21 July 2023 - 14:16 CET.
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