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Receiver
Cold War
British MCR-1 →
  
MCR-1 Bg
Cold War spy receiver

MCR-1 Bg 1 was a valve-based clandestine receiver, manufactured in the late 1950s by Philips subsidary
MBLE
in Belgium, for use by Special Forces (SF) and Stay-Behind Organisations (SBO) during the Cold War. The receiver is basically a copy of the popular British WWII MCR-1 receiver.

Apart from the colour – brown wrinkle paint in­stead of flat grey – and the use of contemporary components and knobs, the design is largely identical to that of the original British MCR-1.

The receiver was suitable for radio frequencies between 150 kHz and 15 MHz 2 divided over four frequency bands, each of which required the use of a dedicated plug-in coil pack (1-4). It was supplied in a green military canvas carrying bag, which had space for the accessories and a battery pack. For radio direction finding (RDF), a foldable loop antenna was supplied separately.
  
MCR-1 with coil pack 1 installed (plug 3 spare coil packs)

The receiver was supplied without a matching power supply unit (PSU), so it is likely that it was intended for use in combination with a suitable battery pack. Although the official production quantity is currently unknown, it is estimated that no more than 100 units were manufactured.

  1. According to the serial number tag, the model name is MCR-1, but since the suffix Bg (Belgium) is present in the part number and on many of the accessories, we have added it here to the model name as well, in order to discriminate it from the original British MCR-1. It is also known as MCR-1 MBLE [1].
  2. With a gap between 1.6 and 2.5 MHz.

Canvas carrying bag MCR-1 with coil pack 1 installed (plug 3 spare coil packs) Standard MCR-1 (front) compared to the MBLE-version of the MCR-1 (rear) Complete MBLE MCR-1 set Headphones Ground pin with wire and plug MCR1 DF loop antenna ready for use Power plug
A
×
A
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Canvas carrying bag
A
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MCR-1 with coil pack 1 installed (plug 3 spare coil packs)
A
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Standard MCR-1 (front) compared to the MBLE-version of the MCR-1 (rear)
A
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Complete MBLE MCR-1 set
A
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Headphones
A
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Ground pin with wire and plug
A
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MCR1 DF loop antenna ready for use
A
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Power plug

Features
The diagram below shows the position of the controls and connections on the (brown) Belgian MCR-1 receiver. At the front is the original (grey) British MCR-1 receiver, which is nearly identical. The device is powered by a separate battery block (not shown here). Antenna (A), counterpoise (E) (ground) and headphones are connected to the four banana sockets next to the power cable.

An original MCR-1 (left) aside a post-war reproduction made by MBLE

Differences with the original MCR-1
  • Colour
    the MBLE version is finished in brown wrinkle paint, rather than flat grey.
  • Knobs
    modern knobs are used on the MBLE-version.
  • Markings
    all text is in French rather than English (and rotated by 90°).
  • Cable
    the MBLE-version has a longer and thicker power cable.
  • Headphones
    the MBLE-version comes with a canvas cloth-type pair of headphones.
  • Sockets
    the sockets on the MBLE-version accept standard banana-type plugs.
  • Components
    modern tuning capacitor and IF coils are used in the MBLE-version.

Parts
Green canvas Carrying bag
Bag
MCR-1Bg receiver Plug-in coil packs Headphones Wire antenna on spool Ground pin Direction finding loop antenna
Carrying bag
The whole set, with the exception of the DF loop antenna, is stowed in a military green canvas bag, which is internally divided into four same-size compartments. One compartment holds the receiver, whilst the others contain the coil packs, the accessories and probably a battery pack.

The carrying bag comes with a canvas shoulder strap, and with an additional strap for attaching it to a soldier's webbing. The lid is held in place by means of two buckles at the front.
  
Canvas carrying bag

Receiver   2S 3000-1 BG
The actual receiver measures 230 x 100 x 60 x mm and weights 1473 grams (with coil pack 1 installed). It is nearly identical to the original British MCR-1 of WWII, except for the colour of the case, the type of knobs and the text labels.

At one end is a set of contact pins, that accept one of four coil packs – or frequency plug-in modules. At the other end is a rubber power cable that should be connected to a suitable LT/HT battery (7.5V and 90V DC).
  
MCR-1 (Bg) receiver

Coil packs
The MCR-1 is suitable for four frequency bands, each of which requires a specific coil pack to be installed on the contact pins at one end of the receiver. The biggest coil pack (1) is for the 150 kHz to 1.6 MHz
MW
broadcast band. The other packs (2-4) span the 2.5 to 15 MHz
SW
band.

The image on the right shows the MCR-1 (Bg) with coil pack (2) installed. The other coil packs (1, 3 and 4) are on the right.
  
MCR-1 with four coil packs (pack 1 attached to receiver)

Headphones
The MCR-1 (Bg) was supplied with a fexible pair of headphones, embedded in green canvas. They can be strapped to the operator's head, and are thin enough to be worn under a soldier's helmet.

The headphones have a fixed cable with a pair of 4 mm banana plugs at the end, that should be connected to the phones sockets of the MCR-1.
  
Headphones

Wire antenna
The best reception is obtained with an outdoor wire antenna, but this is only possible in a fixed setup. The image on the right shows the wire antenna — wound onto a wooden spool — that was supplied with the set.

Note that in this configuration, a counterpoise should be connected as well. This was commonly done by using the ground pin shown below.
  
Wire antenna

Ground pin
When using the wire antenna shown above, it is important to connect a suitable counterpoise as well, in order to obtain the best possible result.

The ground pin should be pressed into the soil as deep as possible, preferably in a place where the soil is not too dry. The wire has a banana plug at the end, which should be connected to the ground terminal of the MCR-1 receiver.
  
Ground pin with wire and plug

Canvas carrying bag Extra canvas carrying strap MCR-1 (Bg) receiver MCR-1 (Bg) receiver Receptacle for coil pack Coil pack 1 detached from MCR-1 receiver MCR-1 with four coil packs (pack 1 attached to receiver) Four different coil packs (1 - 4)
Four compartments inside the canvas bag Opening the canvas carrying bag Headphones (folded) Headphones in canvas carrier Headphones Wire antenna Wire antenna Ground pin with wire and plug
B
×
B
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Canvas carrying bag
B
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Extra canvas carrying strap
B
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MCR-1 (Bg) receiver
B
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MCR-1 (Bg) receiver
B
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Receptacle for coil pack
B
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Coil pack 1 detached from MCR-1 receiver
B
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MCR-1 with four coil packs (pack 1 attached to receiver)
B
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Four different coil packs (1 - 4)
B
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Four compartments inside the canvas bag
B
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Opening the canvas carrying bag
B
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Headphones (folded)
B
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Headphones in canvas carrier
B
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Headphones
B
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Wire antenna
B
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Wire antenna
B
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Ground pin with wire and plug

Loop antenna   2A275 MCR1Bg
When using the receiver in the field, or in a portable application, the use of a wire antenna (and counterpoise) might be impractical. In such cases, the foldable loop antenna – shown on the right – could be used as an alternative.

The antenna consists of three wire loops, which give the antenna some directivity. This has the advantage that unwanted signals (from the sides) are filtered somewhat. Furthermore, it allows the antenna to be used for locating a transmitter (i.e. direction finding, or homing).
  
MCR1 DF loop antenna ready for use

DF loop antenna in canvas carrying bag DF loop antenna with carrying bag DF loop antenna (folded) Folded antenna retaining strap Unfolding the antenna Grip and cable Centre point with four hinged arms MCR1 DF loop antenna ready for use
C
×
C
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DF loop antenna in canvas carrying bag
C
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DF loop antenna with carrying bag
C
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DF loop antenna (folded)
C
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Folded antenna retaining strap
C
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Unfolding the antenna
C
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Grip and cable
C
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Centre point with four hinged arms
C
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MCR1 DF loop antenna ready for use

Specifications
  • Model
    MCR-1 (Bg)
  • Part number
    2D 3000-1 Bg
  • Intermediate
    1730 kHz
  • Valves
    1R5, 4 x 1T4
  • Power
    Dry battery pack LT: 7.5V, HT: 90V
  • Current
    LT: 50mA, HT: 5-8mA
  • Modulation
    AM R/T, CW
  • Dimensions
    Bare receiver: 212 x 100 x 60 mm
  • Weight
    Bare receiver: 1295 grams
Frequency bands
  1. 150 kHz - 1.6 MHz
    85 x 60 x 40 mm (178 grams)
  2. 2.5 MHz - 4.5 MHz
    85 x 60 x 30 mm (152 grams)
  3. 4.5 MHz - 8 MHz
    85 x 60 x 30 mm (154 grams)
  4. 8 MHz - 15 MHz
    85 x 60 x 30 mm (154 grams)
Connection
The image below shows the pinout of the power socket of the battery pack. Although the unit can also be powered by the PSU of the original British MCR-1, this should be discouraged, as it carries the mains voltage on its chassis. Use the British PSU only if you know exactly what your are doing.

Power connections when looking into the power socket of the battery

References
  1. Louis Meulstee, Wireless for the Warrior, volume 4
    ISBN 0952063-36-0, September 2004

  2. Midget Communication Receiver M.C.R. 1
    Original Manual 1943 (14 pages, with circuit diagrams, plus 4 page supplement). 1
  1. Manual scanned and distributed by The Vintage & Military Amateur Radio Society (VMARS).
    Complete overview of freely downloadable manuals here.

Further information
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Crypto Museum. Created: Saturday 23 March 2019. Last changed: Sunday, 24 March 2019 - 10:22 CET.
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