' 



ATMOSPHERIC ATTENUATION AT MILLIMETER WAVELENGTHS 



913 



^^- W^ -^W S 



: li Wi W^- WmWai 'i^ 



Rl 



R3 



Fig. 6 — 750-kc pulses corresponding to the data in Table I. 



Fig. 7 shows the conical horn-lens antenna supported by two bearings 

 to allow adjustment of azimuth and elevation angles. The aperture of 

 the antenna is fitted with a polyethylene lens 30 inches in diameter. The 

 antenna has a gain of about 51 db and a beam width of about 0.5 degrees 

 in the middle of the 5- to 6-mm wave band. This narrow beam, together 

 wath well-elevated reflectors, essentially eliminated ground reflections 

 from the measurements. 



%iM -^ ..«S.JS 



Fig. 7 — Conical horn-lens antenna and mount. 



