16 



CHRONOLOGICAL RECORD 



over-water path between Los Angeles and San Diego, 

 and comparable frequencies between San Diego and 

 San Pedro, a distance of 80 miles over water, using 

 suitable antenna heights. Atmospheric soundings 

 were to be taken from a ship at a point midway along 

 such paths and also on shore as near the midpoint 

 as possible. Measurements with a blimp to determine 

 the extent of uniformity of the inversion layer were 

 also projected. 



Measurements were to continue on fixed radar 

 targets located at various altitudes and along various 

 azimuthal bearings. Field strength measurements 

 were also to be made from an aircraft flown at sig- 

 nificant altitudes over the transmission paths, the 

 results to be correlated with meteorological data. 

 The chairman assisted inauguration of this expanded 

 program by using the Committee's powers and in- 

 fluence in obtaining additional apparatus required. 

 In addition, information was exchanged with mem- 

 bers of a British scientific delegation who were 

 present, and considerable effort was directed to ob- 

 taining a meteorologist for full-time work with the 

 NRSL group conducting the experiment. 



On April 3, Dr. Burrows, Comdr. J. L. Reinartz, 

 and Lt. Comdr. D. H. Menzel visited Panama to 

 observe the experiments being conducted jointly by 

 Dr. Anderson's group and the Navy. 



As a result of this visit, substantially better and 

 more extensive cooperation between the scientific 

 group and Service forces in the area was obtained, 

 and an analysis of the data obtained to date was 

 secured, which revealed occurrence of a predictable 

 surface duct condition. 



A conference was held in Washington on May 2, 

 1944, at which representatives of the various research 

 agencies of the United States interested in propaga- 

 tion were present. A large amount of propagation 

 information was exchanged by presentation of many 

 papers describing various experimental and theo- 

 retical researches going on in various countries. The 

 complete record of papers and proceedings was 

 published by the CUDWR WPG and is contained in 

 the Bibliography at the end of this volume. 



Special consideration was given to the question of 

 symbols and nomenclature by a committee headed 

 by Prof. Attwood. A list of such symbols was pre- 

 pared by this committee and was accepted without 

 dissent by the Wave Propagation Committee of the 

 CCB on May 17, 1944. 



On May 23 the chairman of the Committee on 

 Propagation presented to the NDRC a report on 



what had been accomplished up to that time by the 

 Committee and its plans for the ensuing year, to- 

 gether with budget requirements. The budget was 

 approved with minor deletions in the items covering 

 contingencies. 



On June 29, 1944, a meeting was held at which the 

 progress of the various experimental projects was 

 reviewed in some detail. Two Armed Service requests 

 were also taken up. The first, submitted by Comdr. 

 Menzel and Dr. T. J. Carroll, dated June 12, 1944, 

 outlined the general needs of the Services. Copies of 

 this letter were forwarded to the Committee members 

 for their consideration before the meeting convened. 

 The second was received from General Colton, in 

 the Office of the Chief Signal Officer, and specifically 

 requested a theoretical investigation of the effects of 

 low-level tropospheric layers on propagation at wave- 

 lengths near 10 and 3 cm. 



After discussing specific requirements of the services 

 as laid clown in the Menzel-Carroll letter, certain of 

 the questions were referred to appropriate agencies 

 for solution. In particular, MIT-RL undertook to 

 study the effects of refraction on gunfire control 

 radars operating in the 10- and 3-cm bands. Most of 

 the other questions raised were already under inves- 

 tigation but were not yet sufficiently advanced to 

 permit of conclusive answers. General Colton's re- 

 quest was considered to be covered by the action 

 taken in connection with the Menzel-Carroll letter. 



In addition to progress reports from United States 

 research agencies, a report on British work was sub- 

 mitted, particularly on the status of 9-6-3-cm experi- 

 ments over the Irish Sea. Little useful correlation 

 between propagation and meteorological factors had 

 yet been obtained in this experiment. Projected 

 British experiments included investigation of absorp- 

 tion and attenuation of 10- and 3-cm band radiation 

 in oxygen, in water in all forms occurring in the 

 atmosphere, and in salt spray. 



Late in June 1944, the need for closer liaison 

 between the Committee and CMC was met by the 

 appointment of Major H. Wexler of the Army Air 

 Forces, Weather Division, as a technical advisor. 

 This also strengthened the meteorological represen- 

 tation associated with the Committee, which had 

 not formerly been completely adequate. 



The Committee met at the Radiation Laboratory 

 on August 4, 1944. During this meeting plans were 

 laid for an extensive conference on propagation to 

 be held in Washington, D. C, on November 16 and 

 17, at which representatives of research agencies in 



