1. Defending the Nation Radio Direction Finding

2. Radar Timeline Radar Facts Radar Diagrams and Activities

3. 193519451937193919411943 The British began experiments using RDF (radio direction-finding) equipment. The German Navy created a workable radar set in 1934. ‘The Biggin Hill Experiment’. Practical tests of radar made with the R.A.F. 17 new radar stations were added to the ‘Chain Home’ stations along the English coast. August, 1940. The Lufftwaffe target radar stations in an attempt to ‘blind’ Britain. Radar in the Pacific detected Japanese planes that were about to attack the U.S. naval base at Pearl Harbour. The signals were ignored! Aluminium strips were dropped by British aircraft while bombing Hamburg. These strips caused severe interference on German radar screens. Radar – Interesting Facts Radar Jamming sets were used extensively during the build up to D-Day, making it difficult for the Germans to detect when and where the invasion would take place.

4. The "Radar Stations" were Britain’s first line of defence. They helped to detect enemy aircraft before they reached the British Isles. Signals would be beamed across the English Channel from radio transmitters. These signals would be bounced back to radar receiving stations. Enemy aircraft were shown as ‘blips’ on a radar screen. These ‘blips’ could give a fairly accurate picture of the size, position, height and distance from the British coastline of any enemy raid.

5. How Radar Works A transmitter gives out a radio signal into the air in short bursts. If the signal meets an object (an aeroplane) the radio signal will be reflected back to a receiver. This will show up on a radar screen as a jump, or peak, on a long flat line. From this the approximate direction, distance and height of aircraft could be calculated. This information was passed on to the Operations Room. Fighter Planes were scrambled and a Fighter Controller would then direct those planes to the target. 204060 Target Echo Pulse – Over the 60 mark means the aircraft are 60 miles away.

6. Information received from radar receiving stations Filter Room at Fighter Command HQ begins to plot the enemy raids Information is passed to Group Headquarters The Observer Corps pass on additional information to Controllers as enemy aircraft are sighted Squadrons are scrambled as necessary and guided to enemy aircraft by Controllers Click on the screen to follow the flow of information

7. Radar stations aimed to pick up signals over the English Channel. Dover Chain Home Station Radar masts had receiver aerials that could be up to 350ft-high. The masts, although appearing fragile, presented a difficult target for the Luftwaffe to hit. * Radar was originally called RDF – Radio Direction Finding.

8. Radar Stations, not surprisingly, became a key target for the Luftwaffe during the Battle of Britain. 12 th August – 14 Luftwaffe Bf109’s attacked radar stations that included Pevensey, Rye, Dover and Ventnor. These were difficult targets to hit because of their small size. Three out of the four stations were fully operational again by the end of the day. 15 th August – Once again, Pevensey and Rye Radar Stations were affected when Luftwaffe bombs severed main power lines. Foreness Radar Station suffered the same fate and all three stations were out of action for most of the day. 16 th August – Goering decreed that no further effort should be wasted on attacking British radar stations. This seems a fateful decision, but Goering was determined to put all of his efforts into targeting Britain’s main airfields instead “in view of the fact that not one of those (radar stations) attacked has so far been put out of action.”

9. Fighter Command HQ Airfield Observer Corps Can you mark on the direction of flow of information? Group HQ ‘Sector Operations Room’ Radar Stations

10. Fighter Command HQ Airfield Group HQ ‘Sector Operations Room’ Radar Stations Observer Corps Can you mark on the direction of flow of information?

11. Place the correct information into the empty boxes. These were Britain’s first line of defence. RDF The Luftwaffe found it extremely difficult to target and hit these. Operators Radar was originally known as Radio Direction Finding Radar Stations Radar Masts These could often estimate size, position, height and distance of enemy formations

12. What can you remember about Radar and how it was used during World War Two?

13. Write a short paragraph. Describe the defensive system that existed to protect Britain from air attack? Radar Groups Observers Plotters Squadrons