ABSTRACT
In 1939 eight countries were independently and secretly developing radar. All started in the mid-1930s, the consequence of the availability of two key electronic components: low-voltage, high-vacuum cathode-ray tubes and multi-grid amplifier tubes. Three of these nations quickly out-paced the others and were soon in a technological race without realizing it, as each thought radar to be exclusively its own. It is useful to compare briefly GEMA’s early achievements, so carefully and accurately explained in these pages, with those of Britain and America. How were they similar, and how did they differ?
