The Bell System Technical Journal 



Vol. XXV January, 1^46 No. i 



Early Fire-Control Radars for Naval Vessels 



By W. C. TINUS and W. H. C. HIGGINS 

 Introduction 



FOR a number of years before the war a very intensive development 

 efifort was under way in the Army and Navy laboratories, and in sev- 

 eral commercial laboratories, on the application of radio methods to the 

 location of objects at a distance. The equipment which resulted was 

 eventually called "Radar" equipment by the Navy and this term is now 

 almost universally used. The urgent needs of the war have resulted in the 

 very rapid development and extensive application of this new science 

 during the last few years. 



Radar equipments of many different types have been designed to perform 

 specific functions on land and sea, and in the air. These equipments 

 have had an important part in the winning of the war and the recent re- 

 laxation in secrecy regulations now permits publishing some of the story. 

 In this present article a description of the Mark 3 and 4 Fire-Control 

 Radars for Naval Vessels will be given, together with a little of the history 

 that preceded their development. 



Historical Background 



When the Bell Telephone Laboratories began active radar development 

 work early in 1938 an effort was made to set technical objectives for this 

 work that would avoid duplication of the intensive work then under way in 

 the Army and Navy laboratories, and that would advance the art toward 

 the solution of some of the recognized basic problems. The general ob- 

 jectives were to increase the accuracy of radar measurement of location and 

 to increase as much as possible the operating carrier frequency. The 

 reasons for these objectives are discussed in the following paragraphs. 



The state of the art at the time under discussion has been partially de- 

 scribed in a recent paper by Maj. Gen. R. B. Colton.' The work he de- 

 scribed and directed was carried out at the Signal Corps Laboratories at 

 Fort Monmouth, New Jersey and was directed principally toward solving 



1 "Radar in the U. S. Army" by Maj. Gen. Roger B. Colton, published in the Proceedings 

 of the I. K. E., November, 1945. 



