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Radar System Engineering

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SEC.916] OTHER TYPES OF ELECTRICAL SCANNERS 303<br />

%A$<br />

at about 10 cm nd produces a beam 2° in azimuth by 6.5° in elevation,<br />

which scans 29° one way in azimuth 10 times per second. The antenna<br />

radiates by means of an array of 3 by 14 polyrod radiators (Fig. 932).<br />

Each of the 14 vertical rows of 3 elements is phased as a unit and the<br />

FIc. 9.33.—Cutawaysection of eccentricline scanner<br />

units are phased linearly by a row of rotary phase shifters, each of which<br />

adds 720° of phase per revolution.<br />

An interesting array-type antenna which reached a highly developed<br />

experimental stage is the Long Range, Aircraft to Surface Vessel, LRASV,<br />

corrugated coaxial line array. This antenna was designed to be used<br />

with a 10-cm system, mounted as a long array feeding a reflector along<br />

the side of an airplane, giving a beam 0.8° by 9° for long-range search.<br />

The array, shown in Fig. 9.33, consists of a 15-ft coaxial line whose outer<br />

conductor is pierced with radiating slots spaced at intervals of 2* in.,<br />

which is less than the wavelength. The inner conductor consists of a<br />

~-in. shaft on which are many ~-in. diameter eccentric disks which serve

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