Phase of the Low Radiofrequency Ground Wave UNITED STATES DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS (Published monthly) The National Bureau of Standards is engaged in fundamental and applied research in physics, chemistry, mathematics, and engineering. Projects are conducted in fifteen fields: electricity and electronics, optics and metrology, heat and power, atomic and radiation physics, chemistry, mechanics, organic and fibrous materials, metallurgy, mineral products, building technology, applied mathematics, data processing systems, cryogenic engineering, radio propagation, and radio standards. The Bureau has custody of the national standards of measurement and conducts research leading to the improvement of scientific and engineering standards and of techniques and methods of measurement. Testing methods and instruments are developed; physical constants and properties of materials are determined; and technical processes are investigated. Journal of Research The Journal presents research papers by authorities in the specialized fields of physics, mathematics, chemistry, and engineering. Complete details of the work are presented, including laboratory data, experimental procedures, and theoretical and mathematical analyses. Annual subscription: domestic, $4.00; $1.25 additional for foreign mailing. Technical News Bulletin Summaries of current research at the National Bureau of Standards are published each month in the Technical News Bulletin. The articles are brief, with emphasis on the results of research, chosen on the basis of their scientific or technologic importance. Lists of all Bureau publications during the preceding month are given, including Research Papers, Handbooks, Applied Mathematics Series, Building Materials and Structures Reports, Miscellaneous Publications, and Circulars. Each issue contains 12 or more two-column pages; illustrated. Annual subscription: domestic, $1.00; 35 cents additional for foreign mailing. Basic Radio Propagation Predictions The Predictions provide the information necessary for calculating the best frequencies for communication between any two points in the world at any time during the given month. The data are important to all users of long-range radio communications and navigation, including broadcasting, airline, steamship, and wireless services, as well as to investigators of radio propagation and ionosphere. Each issue, covering a period of one month, is released three months in advance and contains 16 large pages, including pertinent charts, drawings, and tables. Annual subscription: domestic, $1.00; 25 cents additional for foreign mailing. CATALOG OF NBS PUBLICATIONS National Bureau of Standards Circular 460 and its Supplement list all Bureau publications from 1901 through June 1952, including Applied Mathematics Series, Building Materials and Structures Reports, Circulars, Handbooks, Research Papers, and Miscellaneous Publications. Brief abstracts for the publications issued after January 1, 1942, are also included. National Bureau of Standards Circular 460, 375 pages, $1.25. Supplement to Circular 460, 223 pages, 75 cents. (A free mimeographed list of publications issued since June 1952 is available on request to the National Bureau of Standards.) Order all publications from the Superintendent of Documents NATIONAL BUREAU OF STANDARDS A. V. Astin, Director Phase of the Low Radiofrequency Ground Wave ERRATA TO ACCOMPANY National Bureau of Standards Circular/573, Phase of the Page 25, col. 1, C: Insert a minus sign between 33, Table 43: Insert a minus sign before term at top of June 22, 1956 IS.D. 31.2 Issued June 26, 1956 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25, D. C. |