Radar Recollections - A Bournemouth University / CHiDE / HLF project


Radar Jamming - Fooling the enemy

By 1944, the radar systems and the 'jamming' devices used by both the allies and the axis powers were becoming increasingly devious. It was considered essential therefore that as many diversionary tactics were laid before the true invasion of France could begin…

Operation Fortitude:

A large amount of fake aeroplanes and other equipment was constructed in Kent. The idea was to convince the Germans that the US First Army Group under General Patton was going to invade near Dieppe. Fake radio messages were also transmitted. In order for the deception to seem credible however, some sort of fake invasion fleet would have to be conjured.

Operations Taxable and Glimmer:

Dr Cockburn devised a scheme that would show up on German monitoring radar screens to give the impression that a large fleet of ships was heading for Calais. The deception involved the precise release of 'chaff' (aluminium foil) over the channel. To create this illusion, the planes had to fly very low and release the exact amount of 'chaff' at exactly the right time and location otherwise the radar image would be unconvincing. Only the best squadrons could carry out such an exacting task and so 617 (Dambusters) (for Op Taxable) and 218 Squadron (for Op Glimmer) were chosen. The GEE system was employed to help with navigational accuracy. 617 Squadron flew towards Dieppe and 218 flew towards Boulogne.

The plan worked very well !!!

Flight path for operation 'Glimmer'
A schematic plan showing the flight path for operation 'Glimmer'

Operation Moonshine.

A small flotilla and four rescue launches set out armed with 28 radar reflective balloons and a device called 'Moonshine'. Moonshine was a clever piece of electronics that could return and multiply a German radar pulse insuch a way that it would appear to be a large fleet of ships. When just 10 miles off the French coast the balloons were deployed tied to floats and loudspeakers on board played recordings of ships dropping anchor. The whole purpose was to convince the enemy that the invasion was under way when in fact it was taking place far to the west, on the beaches of Normandy….