Modern methods for calculating groundwave field strength over a smooth spherical Earth
Abstract
The report makes available the computer program that produces the proposed new FCC groundwave propagation prediction curves for the new band of standard broadcast frequencies between 1605 and 1705 kHz. The curves are included in recommendations to the U.S. Department of State in preparation for an International Telecommunication Union Radio Conference. The history of the FCC curves is traced from the early 1930's, when the Federal Radio Commission and later the FFC faced an intensifying need for technical information concerning interference distances. A family of curves satisfactorily meeting this need was published in 1940. The FCC reexamined the matter recently in connection with the planned expansion of the AM broadcast band, and the resulting new curves are a precise representation of the mathematical theory. Mathematical background is furnished so that the computer program can be critically evaluated. This will be particularly valuable to persons implementing the program on other computers or adapting it for special applications. Technical references are identified for each of the formulas used by the program, and the history of the development of mathematical methods is outlined.
 Publication:

NASA STI/Recon Technical Report N
 Pub Date:
 February 1986
 Bibcode:
 1986STIN...8627530E
 Keywords:

 Amplitude Modulation;
 Broadcasting;
 Computer Programs;
 Earth Surface;
 Ground Wave Propagation;
 Telecommunication;
 Analysis (Mathematics);
 Conferences;
 International Cooperation;
 Communications and Radar