What was the main factor that initiated serious research on the use of radio echo for detection purposes?

The main factor that initiated serious research on the use of radio echo for detection purposes was the imminent threat of war in Europe. During the period leading up to World War II, nations were increasingly aware of the need for advanced methods of surveillance and detection. This urgency prompted significant investments in technologies that could enhance military capabilities, particularly in the areas of radar and radio detection.

The geopolitical climate drove governments to explore innovative solutions for identifying aircraft and other potential threats at greater distances, as traditional methods were inadequate for the rapidly evolving warfare landscape. The focus on improving detection technology was not just a response to imminent conflict; it also laid the groundwork for further advancements that would prove beneficial in multiple fields, including aviation safety and maritime navigation after the war.