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Radar System Engineering

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76 PROPERTIES OF RADAR TARGETS [SEC. 3.9<br />

and an AT-11 aircraft, respectively, is shown as a function of azimuth<br />

angle.<br />

The airplane in each case was mounted on a turntable in surroundings<br />

free from other reflecting objects, and was observed with a near-by radar<br />

set. The signal strength was automatically recorded as the airplane was<br />

SIOW1y revolved at a uniform rate.<br />

35 db<br />

Fm. 3.S.—Return power from a B-26aircraft at 10-cmwavelength asa functionof azimuth<br />

angle.<br />

In many positions, the power received changes by as much as 15 db<br />

for a change of only ~ in aspect angle. To a lesser, but still very noticeable,<br />

extent the cross section is a function of the position of the propeller,<br />

so that modulation of the received power is produced when the propeller<br />

is rotating (Figs. 3.10 and 3“11). The modulation is far from sinusoidal,<br />

1ikihby, bC. d.

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