A 60-FOOT PARABOLIC ANTENNA FOR PROPAGATION STUDIES 1201 



this angle so that the illumination is tapered to — 10 db at the edge of 

 the paraboloid is not difficult; the horn used is diagramed in Fig. 6, with 

 dimensions given in wave-lengths. The feed horn is mounted in a tripod 

 .support extending out from the front surface of the paraboloid. It is made 

 strong enough so that two 460 mc horns can be mounted side by side. 



The paraboloid itself weighs approximately 53-^ tons; the frontal Avind 

 'load for a 100 mph wind is about 40 tons. It is expected that winds of 

 this force will be withstood. 



The antenna is mounted atop Crawford Hill near Holmdel, New 

 Jersey, at an altitude of 370 feet. It is aimed towards Pharsalia, New 

 i York, a distance of about 171 miles. 



I MEASUREMENT TECHNIQUE 



I The two important properties of the antenna which had to be deter- 



' mined before it could be put into use were its gain and radiation pattern 



at the operating frequencies of 460 mc and 4 kmc. It was also hoped to 



Fig. 2 — Assembling the sectors. 



