The Development of Mandrel

Mandrel was originally designed at Leeson House Langton Matravers a section of the Telecommunications Research Establishment (TRE). It emerged from the necessity to counter the increasing sophistication of German radar systems, particularly early warning radars like Freya and Wurzburg. Freya was 125 miles and Wurzburg, developed in two sizes, small and giant with a range of twenty and forty miles respectively.

In 1942, the scientists, engineers and craftsmen moved to Malvern were tasked with designing a radar countermeasure capable of jamming enemy radars in the 10 MHz bands used by the Germans. The resulting Mandrel device represented a significant technological achievement, employing innovative jamming techniques to disrupt enemy radar signals. The first American countermeasure was not developed until late 1942 and influenced by considerable British design provided by T.R.E Worth who had moved to Malvern between 26 May and 10 June 1942. Even after American bombers went into operation, there was no official countermeasure officer in the American 8th Air Force.

On the 7th December 1942, Pearl Harbour was attacked. Although, the American Radiation Laboratory based in Massachusetts had developed the British Magnetron Valve in 1940 and considered RADAR countermeasures (RCM)  a low priority.

In response to the Japanese Attack, this priority changed to high, the first American Counter Measure Equipment was available in the spring of 1943. With more American equipment became available later in that year.

Operational Challenges and Solutions

Despite its technological prowess, Mandrel faced numerous operational challenges in the field. The dynamic nature of radar technology meant that Mandrel’s effectiveness relied on constant adaptation and refinement. Engineers and technicians experimented with different frequencies, power levels, and deployment strategies to maximize Mandrel’s jamming capabilities.

Despite these efforts, Mandrel experienced mixed success, particularly against the increasing numbers of R.A.F. aircraft in bomber streams, which posed challenges for evasion from Wurzburg radars.

To counter the German Wurzburg and the effectiveness of MANDREL the American Airforce surveyed the invasion beaches prior to the land invasion and found that there were fewer operational Wurzburg RADAR transmitters, possibly destroyed by the earlier aerial attack.

Mandrel’s Role in D-Day:

One of Mandrel’s most significant deployments occurred during the D-Day invasion on June 6, 1944. As Allied forces prepared to launch the largest amphibious assault in history, Mandrel played a crucial role in disrupting German radar detection along the Normandy coast.

Mandrel-equipped aircraft, nine from R.A.F. 214 Squadron Sterling and four US 803 BS (Bomb Squadron) B-17s formed a barrier of electronic jamming, obscuring Allied formations from enemy radar and allowing the invasion fleet to approach undetected. This tactical use of Mandrel contributed to the success of the D-Day landings and demonstrated its importance in large-scale military operations.

The German D-Day Defence

Prior to D-Day the Americans were trying to find the location of the Wurzburg RADARs these provided automatic Gun Laying that directed the gunfire automatically. The down side was it was constructed of a Die Cast material this restricted the transmission of the RADAR to a fixed frequency.

Conclusion: Mandrel stands as a testament to the ingenuity and resourcefulness of wartime technological innovation. From its development in research laboratories into its deployment on the front lines of battle, Mandrel played a crucial role in disrupting enemy radar defences and protecting Allied forces. Its strategic significance, particularly during operations like the D-Day invasion, highlights the critical importance of radar countermeasures in shaping the outcome of World War II. As we reflect on the legacy of Mandrel, we recognize its enduring impact on military technology and the pivotal role it played in securing Allied victory in the fight against tyranny.