Let There Be Light: Radar in the Second World War

Designed by Ji Hong Ni

Without radar, the outcome of the war could have been radically different.

In his recent book, Tools and Weapons, Microsoft President Brad Smith astutely remarks that “Since the dawn of time, any tool can be used for good or ill.”1 While his subsequent focus is largely directed towards the challenges that our society faces today, these words find equal power in the context of the Second World War. The technological innovations developed and used during this time directly contributed to the war’s ‘total’ nature, not only eroding “the limits on the size and scope of the war effort,”2 but also revolutionizing the very essence of warfare itself. A close analysis of the innovations during this war reveals that nonaggressive technologies played a significant role in influencing the war effort. Bold though it may seem, one may even take this analysis a step further and assert that these nonagressive technologies enabled weapons to effectively achieve the level of destruction that has earned the Second World War its place in the history books. Nowhere is this more evident than in the case of radar.

There are two major events in which radar played a pivotal role. The first is the Battle of Britain in 1940, an aerial military operation in which the British forces successfully defended their country against the German Luftwaffe. Being an island, England primarily faced military threats from the sea and sky, unlike its fellow European countries. Even before the outbreak of the war, there was a “growing fear of German air raids which induced the British to establish”3 the Chain Home radar defense system in 1938. The need for this technology became even clearer following Germany’s swift defeat of France at the onset of the war, as the British were naturally perceived as the next target of attack. Focusing purely on manpower, the Battle of Britain may seem deeply imbalanced in terms of military might. At the beginning of the battle, the Luftwaffe forces tallied at 4074 aircrafts, whereas the Royal Air Force (RAF) aerial forces numbered at a mere 1963 aircrafts. What is more, the Germans far outnumbered the British in every class of plane save except one.4 Despite the fearsome reputation that the British Spitfires and Hurricanes enjoyed as top-class fighters, it would be hard to accept British victory as a feat of prowess alone. 

The use of radar by the British forces can in fact address the imbalance between this numerical disadvantage and the actual outcome of the battle. Although the Germans did understand radar technology at the time and were aware of the existence of Chain Home, they underestimated its range and accuracy. What the Germans perhaps did not realize was that “Nazi bombers taking off from France were watched by English radar throughout their entire flight no matter how roundabout their route.”5 Britain’s ability to identify the flight patterns of the Luftwaffe granted them the ability to anticipate the positioning and ultimate destinations of the German forces. The British fighters, although vastly outnumbered, were able to fend off the German forces with surgical precision, resulting in their foiling of Luftwaffe raids time and time again. This use of radar perfectly reflects Churchill’s description of its implementation as focused on “operational efficiency rather than novelty of equipment;”6 while arguably simple in design and limited in capabilities, the Chain Home system – and radar technology generally – was crucial for the RAF’s victory in 1940 in the Battle of Britain despite their staggering numerical disadvantage.

The power and influence of radar manifested itself “not only in the Battle of Britain and the air war over Germany but in the war at sea.”7 A key example of this is the Battle of the Atlantic, a naval conflict that spanned the duration of the entire Second World War and ultimately resulted in an Allied victory. U-Boats [German submarines] “were still not equipped with radar”8 in 1942-43. The Germans consistently lagged behind the Allied forces in the development of radar technology, having grown complacent with their initial radar innovations early on in the war. The Allies, however, significantly developed their radar technology around 1943 “to locate ships as well as planes, a process which showed its utility in the location and sinking of German submarines in the Atlantic and the battleship Scharnhorst off the Norwegian coast.”9 A variant of radio and radar-like technology additionally played a very significant and interesting role in naval warfare: High-frequency Direction Finding (HF/DF). Time and again “the U-Boats were driven off with the balance of losses shifting steadily against them: in May the Allies were sinking them at the rate of one per day out of the over 120 out in the Atlantic.”10 Even more important than these mere statistics were the misguided beliefs that the Germans developed concerning HF/DF, wrongly blaming the radar carried by airplanes for their casualties. Their attention was diverted away from HF/DF technology to the extent that the “Germans never caught on to this device and ascribed all Allied ability to locate U-Boats running on the surface to their use of radar”11 technology. Given that it was through HF/DF that convoy escorts were more frequently able to locate submarines on the surface, this enabled the Allied forces to identify and destroy their targets with less interference from the enemy. 

The development and use of radar technology clearly had significant impacts on the course of the Second World War. Had British radar not been developed or implemented to an advanced degree, the RAF would have undoubtedly lost the element of surprise, precision and, as the Luftwaffe forces far outnumbered those of the RAF, potentially the Battle of Britain itself. It is furthermore important to note that this would have been no trifling defeat in the broader context of the war: the destruction of the RAF would have left England more vulnerable to aerial threats, threats that the naval forces alone would not have been able to stop. The inevitable destruction to cities and civilians may have brought the country to its knees, thus potentially forcing a British surrender to the German forces. The only remaining European superpower would have been eliminated as an obstacle to Hitler’s goals, which may have additionally prevented – or at least delayed – the US from joining the war: they were already seemingly reluctant to go to war against the Germans without the aid of the British. This might have allowed Hitler to direct more of his forces towards the Soviet Union. Given that Stalin was arguably already contemplating “the possibility of a separate peace either with Hitler’s Germany or with some alternative German government”12 in 1943, the complete lack of allies may have catalyzed this process and granted a German victory in the Second World War.

The Battle of the Atlantic additionally provides insight into the extent to which HF/DF and radar technology were instrumental to the Allied war efforts. The use of such devices by the Allies enabled them to not only directly identify U-Boats, submarines, and other naval threats, but also to indirectly track sea activity. Without the ability to execute either of these functions, the Allies would have been vulnerable to sudden naval attacks and forced to develop reactionary as opposed to anticipatory tactics. This hindrance would in turn have two tangible consequences: first, the Allies would not have been able to sink the German naval forces at the same rate, which in turn could have prolonged the duration of the war. Secondly, while they might have relied on alternative intelligence to fill this void, these reports could have been outdated or worthless by the time they were decoded. One may be inclined to argue that the Allies’ use of radar was the crucial factor in addressing the German naval threat. Such logic has profound implications on the rest of the war. Given Britain’s status as an island, access to the country could only be gained via sea or air. German control of the sea would vastly reduce allied support to Britain and leave the country virtually defenseless. Furthermore, the transportation of British goods to various Allied nations was achieved either by warships or warplanes, with the routes to Europe and even Russia relying on access to the Atlantic.13 Cutting off these supply routes would have exacerbated the mounting adversities faced by the Allies and perhaps catalyzed their surrender.

Radar is a technology that is not fundamentally driven by violence; today, we still use it in cars, air-traffic control, and even astronomy. And yet, we have seen its instrumental impact in the Second World War, granting countries the ability to achieve and prevent destruction at unprecedented levels. Without radar, the outcome of the war could have been radically different. We can draw a similar lesson regarding the plethora of nonaggressive technologies that were also produced and developed upon during the war, each granting newfound power and capabilities. Radar — and many other “nonaggressive” technologies — played as crucial a role in influencing the events of the Second World War as advancements in weaponry.

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