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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.
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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.
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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.
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Digital Message Device (DMD, MEROD, TDED)
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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.
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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
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Electronic Message Unit (EMU)
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The SE-6861 was often used in combination with an
Electronic Message Unit (EMU)
for the secure exchange of secret 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 at very high speed (burst), in order to
minimise the risk of detection and interception. Most EMUs also use some level
of cryptography to keep the message secure.
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A typical example of an suitable EMU is the
Nokia PARSA (Partiosanomalaite)
shown here.
It is a small portable unit that can be attached to the
soldier's webbing.
It is powered by its own internal batteries and short
messages can be entered on a rubber key pad, together with the message key.
The message is displayed on a red single row 16 character LED display.
More information
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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.
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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.
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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
a Harris radio set.
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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.
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- 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
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- Anonymous source, Images of Dutch Special Forces using MEROD
Photographs reproduced here with permission from the owner. March 2012.
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© Copyright 2009-2013, Paul Reuvers & Marc Simons. Last changed: Friday, 11 January 2013 - 11:38 CET
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