Radar Observer · Limitations — Second Trace
Second-trace (multiple-trace) echoes occur under abnormal propagation when:
- AGain is set too low
- BA distant target's echo returns after the next pulse has been transmitted and is shown at a false short range✓ Correct
- CThe antenna stops rotating
- DTwo radars interfere
Explanation
Under ducting, energy reaches a target beyond the normal maximum range; its echo arrives after the next pulse fires and is plotted at a short, false range. Changing the pulse repetition rate (range scale) reveals it as the false echo moves.
Authority: Radar Navigation — Anomalous Propagation
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