Chapter I 

 ORIGIN AND ORGANIZATION 



1.1 



ORIGIN 



IN august L943, Dr. Iv. T. Compton, a member 

 of the National Defense Research Committee 

 [NDRC], in the course of discharging his duties 

 resulting from his "radar mission" to England, asked 

 Dr. Chas. R. Burrows of the Bell Telephone Labora- 

 tories if he would undertake the coordination of 

 research work on radio wave propagation in the 

 United States under the auspices of NDRC. This 

 was the initial step in the formation of the Committee 

 on Propagation. During the Compton radar mission 

 the urgent need for radar information in the armed 

 forces was discussed by Dr. Compton and Sir Ed- 

 ward Appleton. 



The Committee on Propagation of the National 

 Defense Research Committee was organized in 

 August 1943, under the chairmanship of Dr. Burrows. 

 This body was created for the purpose of coordinating 

 American scientific investigation of the propagation 

 of electromagnetic waves through the lower atmos- 

 phere (troposphere), correlating the United States 

 research with that being carried out in Great Britain 

 and other countries of the United Nations and trans- 

 mitting the information obtained to the Armed 

 Forces in usable form, as speedily as possible. 



It was decided that the propagation phenomena 

 referred to could be divided into two classes: one, 

 the effects of the troposphere itself on electromag- 

 netic radiation of the wavelengths under discussion 

 and, two, the effects of the earth's land and water 

 surfaces in reflecting radiation incident at various 

 angles. A British memorandum dated April 28, 1943 

 was drawn up, inviting specific United States cooper- 

 ation in investigation of the following problems: 



1. The entire question of effects of tropospheric 

 conditions near and over a continental land mass 

 similar in size, climate, and topography to Europe, 

 on radiation of radar frequencies, in meteorological 

 environments ranging from polar to tropical, with 

 particular emphasis on obtaining quantitative data. 

 British facilities and environments for this investi- 

 gation were limited. 



2. An exhaustive study of propagation under 

 desert and moist tropical conditions, particularly 

 with transmitter and receiver at heights of less 

 than 100 ft. 



3. Propagation under temperate climatic condi- 

 tions with either the receiver or transmitter at heights 

 from 5,000 to 10,000 ft. 



4. Experiments to determine the dependence of 

 the reflection coefficient on the ang'e of incidence 

 with the surface of a rough sea. 



5. Experiments along nearly optical paths over 

 various kinds of topography likely to be encountered 

 in field operations. Exhaustive knowledge of this 

 aspect of the general propagation problem appeared 

 to be an urgent necessity, and comparison of United 

 States and United Kingdom experience was con- 

 sidered highly desirable. 



It was felt that such investigations, correlated 

 with parallel work on those aspects of the research 

 which could be carried out in Great Britain, would 

 produce early results of great importance to the 

 successful prosecution of the war. 



It was extremely important for the armed forces 

 to know with reasonable accuracy the coverage to 

 be expected with given radar or radio communica- 

 tion equipment under various conditions of terrain 

 and meteorology. In order that this coverage could 

 be determined it was necessary to know the laws 

 governing electromagnetic wave propagation, and 

 these laws could be derived only by an extensive 

 theoretical and experimental research program. The 

 urgency and importance of the entire matter of cover- 

 age become obvious when the following pertinent 

 aspects of modern warfare are considered: 



1 . The development of highly mobile and powerful 

 instruments (such as the improved tank and other 

 surface combat vehicles, and of long range, high 

 speed bombardment aircraft employed for strategic 

 attacks on the means of production and civilian 

 morale, as well as for tactical purposes) which per- 

 mitted the principal belligerents to readopt a war 

 of movement, instead of one of static fortification 

 and attrition, and made the development of devices 

 for detecting the presence and movements of enemy 

 mobile units vitally necessary. 



2. The necessity of protecting extremely extended 

 sea and land supply lines from successful attack by 

 enemies who early realized that their major hope of 

 ultimate victory lay in cutting those lines. 



3. The enormous extent and diversity of the 

 various theaters of operations, necessitating inte- 



