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AEG Telefunken SE-6861   LAPR
Long-distance HF manpack radio

The SE-6861 was a military-grade manpack radio station, developed in 1976 by AEG Telefunken in Ulm (Germany) as part of a range of military radios. Strickly speaking it was not a spy radio set, but it was heavily used by Special Forces (SF), often in combination with secure message devices.

The SE-6861 is shown here is its typical canvas back pack, with side pockets for the antenna's and the handset. The frequency of the unit can be set between 1.5 and 30 MHz in 100Hz steps, using a series of push-buttons hidden behind a small metal flap (shown here with flap open).

The actual radio set is much smaller as can be seen in the images below. The bare unit consists of two parts: the upper part which is the actual radio set, and the lower part that contains the rechargable batteries. Two spring-loaded clamps at the sides are used to hold them together.
  

The SE-6861 was suitable for a 30 to 1500 km range and was the standard radio set with many Special Forces world-wide during the 1980s en 1990s, such as in Germany and in The Netherlands (see below). In The Netherlands it was known as LAPR, which is short for Lange Afstand Ploeg Radio (Long Distance Group Radio). The radio was replaced in the late 1990s by modern radio sets, such as Harris, and later by digital radio equipment.

The SE-6861 packed in the original canvas back pack. Typical view inside the bag The SE-6861 ready for use. Shown in back pack with the original handset. Right view of the bare SE-6861 unit Left view of the bare SE-6861 unit Front view of the unit with opened flap Close-up of the front panel with the frequency buttons visible The SE-6861 with the Nokia Parsa EMU
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The SE-6861 packed in the original canvas back pack.
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Typical view inside the bag
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The SE-6861 ready for use. Shown in back pack with the original handset.
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Right view of the bare SE-6861 unit
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Left view of the bare SE-6861 unit
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Front view of the unit with opened flap
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Close-up of the front panel with the frequency buttons visible
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The SE-6861 with the Nokia Parsa EMU

Controls
Operation of the SE-6861 is really straightforward. The MODE-selector at the top center is used to turn the set ON and OFF and to select the desired MODE of operation. The user can select between USB and LSB, and between voice (J3E) and CW (A1A). Another selector, at the bottom left, is used to select the appropriate antenna (rod, wire or external) and the desired RF output power (2W or 20W). The built-in antenna tuner is used on combination with a rod/wire antenna.


The current frequency can be set with a series of UP/DOWN push-buttons at the right, in steps of 100 Hz. Another UP/DOWN selector, to the left of the MODE selector, can be used to select one of four memory channels. Setting this selector to 0 (zero) selects the current frequency. Any of the other memory locations can be programmed, using the PRESET button at the bottom right.

A suitable handset or headset can be connection to any of the two sockets at the right. These sockets can also be used for the connection of a message unit or a crypto device. An external antenna can be connected to the BNC socket at the top left. When operating the radio in the dark, the orange push button at the center of the ANTENNA/POWER selector can be used to turn on scale illumination. Audio volume can be set in 7 steps using another set of UP/DOWN buttons.


Digital Message Device (DMD, MEROD, TDED)
In the UK and in The Netherlands, the SE-6861 was often used with a Racal MEROD (Message Entry and Read-Out Device), such as the MA4248, the MA4450 and the MA4480. For the US market, Racal developed a special version of the MEROD, that was known as the KY-879/P.

The image on the right shows a typical Racal MEROD unit, the MA-4450, with was used in combination with a variety of radio sets, including the SE-6861. It is shown here in its protective nylon carrying puch with the optional illumination lid opened.

The pouch has several pockets for holding the various cables, accessories and a junction box. They can be packed in such a way that the entire unit is ready for use at any time. For a long time, MEROD devices were standard issue with Special Forces (SF) in many countries.

 More information
  
MEROD MA-4450 in carrying pouch, with lid open

Electronic Message Unit (EMU)
The SE-6861 was often used in combination with an Electronic Message Unit (EMU) for secure exchange of messages. The main advantage of using an EMU is that the message can be prepared off-line. Once the message is complete, it is transmitted in encrypted form, at very high speed (a burst transmission), in order to minimise the risk of detection and radio direction finding (RDF).

A typical example of an suitable EMU is the Nokia PARSA (Partiosanomalaite), or Philips UA-8296, shown here. It is a small portable unit that can be attached to the soldier's webbing.

The unit is powered by its own internal batteries or by the radio to which is it connected. Short messages can be entered on a rubber key pad, together with the message key. The message is displayed on a red 16-character LED display.

 More information

  
Nokia PARSA

Telestar
The SE-6861 was sometimes used with the Telefunken Telestar 121 or 122, either in clear or with the TELEKRYPT DAT-812 encryption unit.

The Telestar was a compact rugged teleprinter with a built-in thermal printer and (optionally) a radio interface. It was used by the German Police, the Bundesgrenzschutz (BGS) and NATO .

 More information

  
Telefunken Telestar 121

Dutch Special Forces
In the Netherlands, the SE-6861 was introduced in the early 1980s, with the Special Forces (104 Waarnemings- en Verkenningscompagnie). It was called LAPR, which is short for Lange Afstand Ploeg Radio (Long Distance Group Radio) and was given the internal designator KL/TRC-5151.

The SE-6861 was used in combination with a Racal MEROD crypto unit, either the MA-4248, the MA-4450 or the MA-4480 which was given the designator KY-55590/TGC-5551. The common Dutch name for it was DBA (Digitaal Berichten Apparaat).

The SF 104 used this rig to operate from behind enemy lines, after infiltration during the night or after having been dropped as a parachutist. They would hide themselves underground and operate from there. They often used inconspicious NVIS wire antennas, such as the well-known WINDOM.
  
Dutch Special Forces using MEROD in the field

The image above shows Dutch Special Forces in an underground hideout [1]. The soldier in the picture is entering a message on his MEROD device (DBA). The SE-6861 (LAPR) is visible in the top right. The messages were first converted into a series of short message blocks and were then converted into 'nonsense' using the DBA crypto unit with a built-in AFSK modem.

The radio was operated in an acurate time and frequency scheme, which was very difficult to predict for an outsider. As a result, the radio station was very dificult to intercept and trace. All messages were monitored and recorded in a central listening post comprising a few radios, a PC and the Racal Message Base Station MA-4420 (KY-5589/TGC-5578). The messages could be printed onto paper in a format that was comprehendible for INTEL-people.

Another photograph (below) shows the same MEROD device (DBA) in use in a Dutch command center [1]. In the early 2000s, the Dutch Special Forces dropped the SE-6861 in favour of Harris radio equipment.

Dutch Special Forces using MEROD in the field Dutch special forces using MEROD in a command center
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Dutch Special Forces using MEROD in the field
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Dutch special forces using MEROD in a command center

Headset
The SE-6861 was supplied with its own suitable headset. In many cases however, it was used in combination with the Racal headset shown here, because of the much higher audio quality.   

Technical Specifications
  • Frequency range: 1.5 - 30 MHz in 100Hz steps
  • RF outout: 2W or 2W PEP
  • Built-in Antenna Tuning Unit ASG-6861
  • Modulation: J3E (SSB) in LSB or USB, A1A (CW) and (optionally) FSK
  • Memory channels: 4 + 1
  • Receiver, 1st IF: 20 MHz
Documentation
  1. 20W HF Manpack Transceiver SE-6861/12 mod, Operating Instructions
    AEG Telefunken. Date unknown.

  2. Brochure, Funkschreib-Einrichtung FFT-6856 / SE-6863
    Feldfunkgerät SE 6861 Datenblatt. Funkschreib-Terminal FFT 6856.
    N 116.106.0. AEG Telefunken. Ulm (Germany).
References
  1. Anonymous source, Images of Dutch Special Forces using MEROD
    Photographs reproduced here with permission from the owner. March 2012.
Further information
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Crypto Museum. Created: Friday 27 January 2012. Last changed: Tuesday, 10 October 2017 - 11:19 CET.
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