Tactical pulsed doppler radar
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ZB-298 was a mobile tactical ground-based static pulsed doppler radar,
developed by Marconi-Elliot Avionic Systems Ltd. in Borehamwood (UK) around
1965. The device was intended for use by reconnaissance units and delivered
a acoustic and visual output. It was used until the mid-1990s.
The unit operates in the 3 cm (10 GHz) X-band, and consists of a
control unit that is connected to a rectangular antenna that is mounted
on a tripod. Both the rotation and elevation angle
of the tripod can be altered from the control unit.
The radar was typically used by infantry reconnaissance units and had
an operational range from 50 metres to 10 km. From the acoustic output,
based on the doppler-shift caused by a moving object, a well-trained operator
could recognise people, animals, vehicles and tanks, and even give an
indication of their volume.
The visual output was used to determine the distance and size of the object.
Through a lens on the control unit, the operator could see two faint red
lines. The first line was caused by the radar's pulse and represented the
station's position. The second red line was caused by the reflection and
was written by means of a laser and a rotating mirror. The distance
could be read from a scale.
The size of the object was determined by first rotating the antenna to the
left until the object was lost. Next the antenna was rotated to the right until
the object was lost. The difference in angle was used with the measured
distance to calculate the size of the object.
For this reason, a circle was divided into 1000 units (rather than 360 degrees)
which makes the calculations easier.
As an example: an object with an opening angle of 3 units,
at a distance of 1 km, is 3 metres wide.
The ZB-298 was developed around 1965 and was used that same year by the British
Armed Forces in Borneo, although this was not admitted until seven years
later in 1972 .
The radar was introduced with the rest of the British Army in 1971,
where it was known as Radar GS No. 14.
It played in important (secret) role in the fight agains the IRA
in Northern Ireland.
It was later also introduced with some of the NATO partners,
like Denmark and The Netherlands.
By the mid-1980s the ZB-298 had become dangerous and obsolete
but was kept in use until the mid-1990s.
The system was portable but heavy, and could be carried by two people.
When used in the field the antenna was mounted on a tripod that was marked
in thousands (rather than degrees).
When used on a vehicle, it was usually mounted on top of the vehicle
by means of an electrically movable head.
In the Netherlands, the ZB-298 was installed on the YP-408 RDR infantry
vehicle and later also on the YPR-765 PR-RDR track-based reconnaissance
vehicle, as shown below.
Pulsed radar systems, like the ZB-298, have a high-power Klystron that
transmits a rather strong radio signal. This signal can easily be picked up
by an eavesdropper or by an enemy reconnaissance unit with suitable equipment. This makes such radar systems potentially dangerous.
In the mid-1980s, it gruadually became known to Western intelligence that
the signal from a static pulsed-doppler radar system could be detected and
could be used to determine its location.
In the early 1970s, the Czechoslovakian company
Tesla had already developed
a small portable radar locator, known as the
MPR-4, which could detect,
identify and locate any radar in the 1 - 10 GHz range. The MRP-4 could
be carried on the chest and produced an acoustic feedback to the operator
through a small in-ear speaker. It also had a meter that produced a visual
Althoug the MRP-4 was initially developed for the Czechoslovak Army, it was
later successfully sold to most other countries of the
Warsaw Pact and to the
Soviet Union (USSR),
where functional duplicates were made as well. The MRP-4
was deployed with every reconnaissance unit of the Czechoslovakian Army and
also with the Special Forces of the Hungarian Army. As a result, the ZB-298
became a dangerous device that was gradually phased out. Nevertheless it
took until the mid-1990s, way past the end of the
Cold War, before the units
were oficially declared obsolete.
➤ More about the MRP-4 radar locator
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© Crypto Museum. Created: Thursday 28 July 2016. Last changed: Friday, 02 June 2017 - 06:54 CET.