History
The first early warning radars were the British Chain Home, the US CXAM (Navy) and SCR-270 (Army), and the German Freya. By modern standards these were quite short range, typically about 100 to 150 miles. This "short" distance is a side effect of radio propagation at the long wavelengths being used at the time, which were generally limited to line-of-sight. Although techniques for long-range propagation were known and widely used for shortwave radio, the ability to process the complex return signal was simply not possible at the time.
Read more about this topic: Early Warning Radar
Famous quotes containing the word history:
“So in accepting the leading of the sentiments, it is not what we believe concerning the immortality of the soul, or the like, but the universal impulse to believe, that is the material circumstance, and is the principal fact in this history of the globe.”
—Ralph Waldo Emerson (1803–1882)
“Regarding History as the slaughter-bench at which the happiness of peoples, the wisdom of States, and the virtue of individuals have been victimized—the question involuntarily arises—to what principle, to what final aim these enormous sacrifices have been offered.”
—Georg Wilhelm Friedrich Hegel (1770–1831)
“To summarize the contentions of this paper then. Firstly, the phrase ‘the meaning of a word’ is a spurious phrase. Secondly and consequently, a re-examination is needed of phrases like the two which I discuss, ‘being a part of the meaning of’ and ‘having the same meaning.’ On these matters, dogmatists require prodding: although history indeed suggests that it may sometimes be better to let sleeping dogmatists lie.”
—J.L. (John Langshaw)