Condign volumes 1 to 3

Read from the scan by GLM-OCR; expect the odd misread word.

## UNCLASSIFIED

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object might have. The steady (non-fluctuating case), sometimes called Case 5, is extremely rare in normal radar practise, due to the inherent nature of flying targets. (R)

5. Practical Effects The detection capability of a radar depends upon the signal (wanted) to noise (unwanted) ratio. The practical effect of RCS fluctuations, applicable to the UAP scenario, is most simply illustrated by one example. For a typical radar with a requirement of probability of detection of 0.95, against a steady target, a signal/noise ratio of 4 ( $ \sim 6 $ dB) is required. If the target is fluctuating according to Case 1, above, a ratio of $ - 4 8 $ (16.8dB) would be necessary. In radar range terms this turns out to be a range performance reduction by a factor of 3.28. This effect can be mitigated somewhat by illuminating the target with a larger number of pulses and averaging them out. However, there is a limit to the number of pulses emitted, and which impinge on a target from an early warning-type radar during its typical continuous-scan mode of operation. For targets which exhibit Case 3 and Case 4 fluctuations the situation is even worse and it is believed that this is the case for most, if not all, of the plasma UAP events. Hence, the factors which account for the intermittent detection of most UAP events on the radars, can be well justified in engineering and scientific terms. The precise limitations on the UKADR radars are discussed at Volume 3.(U)