Description
Object description
British transmitter type TR1657 Mark XI, operating on 148 MHz to 196 MHz, part of Mandrell III airborne radar jamming system. Stores reference 10D/16334.
Physical description
Mandrel ECM
History note
RAF Bomber Command did not,initially ,show any
interest in RCM (Radio Counter Measures, now
called ECM). Its campaign in the early years
(1940 -42) was ineffective, but aircrew were not
aware of any serious radar threat, and were more
concerned about maintaining radio silence
Telecommunications Research Establishment
(TRE) were more informed because of sigint
from 80 Signals Wing and the RAF Y-Service.
Moreover, on 12 February 1942 the dramatic
Channel Dash of the Kriegsmarine had involved
extensive jamming of British coastal radars.
The Bruneval Raid on 27/28 February, and the
seizure of parts of a Wurzburg Set, confirmed
the German electronics and radar threat.
The TRE -designed Mandrel was the first of
Bomber Command's RCM/ECM devices. It was
designed to jam the enemy's EW (Early warning)
radars in 10 MHz bands (Freya, Jagdschloss,
Mammut, Wassermann etc). It was first
deployed by RAF Bomber Command during the
night of the 5/6 December 1942, in an attempt to
jam Freya radars which, along with Wurzburg
GCI (Ground Control Interception) radars,formed
the German Himmelbett radar air defences.
Mandrel enjoyed mixed success.It could jam
the Freyas, but the increasing numbers of
RAF aircraft in the bomber stream meant that
the Wurzburgs could still detect their targets.
Mandrel's use as a jammer was also
compromised by the ability of Y-Dienst to detect
its emissions.
Among Mandrel's finest hour was the D-Day
invasion operation . Several squadrons used
Mandrel jammers to protect the advancing
invasion force from German radar detection, on
a line from the Bill of Portland to Littlehampton.A
reinforced squadron used Mandrel to screen a
thousand transport aircraft carrying airborne
troops for the landings east of Caen and on the
Cherbourg Peninsula.
Engraved plate
Type TR 1657X1 Ref No 10D/16334 AM
Serial No TE 237