RADAR ANTENNAS 



309 



The "Track" antenna operates in the 10 cm. region and consists of a reflec- 

 tor which is a parabola or revolution, 57 inches in diameter, illuminated by a 

 source of energy emerging from a round waveguide in the lobing mechanism. 

 Conical lobing is achieved by rotating the source of energy around the 

 parabola axis in the focal plane of the parabola. Conical lobing is discussed 

 in section 11.2. The round waveguide forming the source is filled with a 

 specially shaped polystyrene core to control the illumination of the para iola 

 and to seal the feed system against the weather. The radio frequency power 

 is fed through coaxial transmission line to a coaxial-waveguide transition 

 which is attached to the lobing mechanism. 



The "Search" and "Track" antenna lobing mechanisms are synchronized 

 and driven by a common motor. 



The radio frequency power for both antennas is transmitted through a 

 single specially constructed coaxial transmission line to the common antenna 

 structure, where a coaxial transmission line filter separates the power for 

 each antenna. 



Figure 58 is a photograph of a production model of the SCR-545 Radar 

 Set. The principal electrical characteristics of the antennas are tabulated 

 below: 



The SCR-545 played an important part in the Italian campaign, particu- 

 larly in helping to secure the Anzio Beach Head area, as well as combating 

 the "V" bombs in Belgium. However the majority of SCR-545 equip- 

 ments were sent to the Pacific Theater of Operations and played an im- 

 portant part in operations on Leyte, Saipan, Iwo Jima, and Okinawa. 



15.2 The AN/TPS-IA Portable Search Antenna^ 



In order to provide early warning information for advanced units, a light 

 weight, readily transportable radar was designed under Signal Corps contract. 



i« Written by R. E. Crane. 



