( OMM1TTKK \CTIVITIKS 



17 



all the countries engaging in propagation research 

 could present findings to date. 



Plans were laid for Dr. Anderson's trip to the 

 Southwest Pacific theater in response to General 

 MacArthur's request for investigation of propagation 

 phenomena. This project was of considerable im- 

 portance and is more fully described elsewhere in 

 this report. 



A report by Dr. Svein Rosseland, assistant to Prof. 

 Attwood in the CUDWR WPG, was heard, on work 

 going on in England and on data brought back to 

 that country by Dr. Booker. These data described 

 radar echoes from points more than 1,500 miles 

 from the 200-mc Bombay, India, station, which had 

 been observed during the season following the 

 northeast monsoon. 



Other reports were heard on Bell Telephone 

 Laboratories [BTL] experiments on K band along 

 a path to Atlantic Highlands and similar experiments 

 by MIT-RL near Boston. No nonstandard propaga- 

 tion had been observed at Atlantic Highlands, but 

 some had occurred in the Boston area. 



Experiments of MIT-RL along a ten mile path 

 had indicated the impossibility of measuring the 

 effect of oxygen and water vapor outside the labora- 

 tory itself. 



Dr. W. H. Furry described the work of preparing 

 coverage diagrams for radar and VHF (very high 

 frequency) communication equipment under ground- 

 based duct conditions. Owing to the volume of 

 calculations required in this work it was decided to 

 obtain use of the Harvard University automatic 

 sequence-controlled calculating machine, which 

 would effect a probable reduction in the time required 

 from an estimated nine or ten months to about three 

 weeks. This proposal was subsequently carried out. 



Dr. Beverage presented certain problems of Divi- 

 sion 13, particularly the need for supplying the best 

 information on" probable coverage to signal officers 

 in the field at the earliest possible date. Estimates 

 based on the 4 A earth radius formula tended to be 

 pessimistic. 



Dr. H. Goldstein presented information on the 

 problem of fluctuating signals. Instability in the 

 equipment was a source of great difficulty, but, when 

 this had been overcome, such results as were obtained 

 indicated that most fluctuation was due to inter- 

 ference. 



Plans were made for a field trip to observe the 

 extensive MIT-RL experiments proceeding on four 

 different wave bands along a path between Race 



Point and Gloucester. On this trip the entire ap- 

 paratus and organization of the experiment were 

 inspected and discussed. 



A detailed memorandum of the Committee's 

 current work was submitted on August 10 to the 

 Chiefs of NDRC Divisions 13, 14, and 15, in order 

 to keep these groups informed of developments. The 

 breakdown of activities described five well-controlled 

 experiments which were under way in different 

 meteorological environments and the theoretical 

 attack proceeding in Britain and the United States. 

 These experimental attacks on the problem have 

 been described earlier in outlining the Committee's 

 program for the year. The memorandum referred to 

 here specifically invited Division comment on the 

 program in progress and requests for other investi- 

 gations if additional ones seemed desirable. 



A Committee meeting on September 21, 1944 

 considered new humidity measuring instruments and 

 reviewed progress of the work under way at RL. 

 This was reported by D. E. Kerr as nearing the conclu- 

 sion of the experimental work. The matter of educa- 

 tional films to disseminate propagation information 

 to the Services was brought up, and the need for a 

 technical aide to the Committee who should be 

 familiar with NDRC procedure was discussed. Dr. 

 Burrows stated that efforts were being made to 

 obtain a contractor who would make meteorological 

 measurements along the BTL to Mt. Neshanic prop- 

 agation path, for correlation with the transmission 

 data available at BTL. These measurements were 

 later undertaken by the Airborne Instruments Lab- 

 oratory [AIL] of Mineola, Long Island. The matter 

 of eventual demobilization of OSRD was discussed, 

 particularly as to effects of such demobilization on 

 investigations of propagation then in progress. 



The Committee met again on November 15, 1944 

 to consider replies received from Divisions 13, 14, 

 and 15 to the memorandum outlining its program in 

 progress submitted on August 10 and to transact 

 other business. The matters of calculation of radar 

 coverage diagrams for nonstandard conditions, of 

 the range and reliability of very high frequency 

 [VHF] and ultra high frequency [UHF] communica- 

 tions links, and the choice of frequencies for such 

 links were taken up in detail. After thorough con- 

 sideration, a reply was drafted for the Divisions 

 concerned, particularly Division 13, stating that 

 available information on propagation did not permit 

 preparation of accurate coverage diagrams for such 

 communications circuits on any other basis than 



