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ESSA Technical Report ERL 73-ITS 63

Numerical Maps of foEs for Solar Cycle Minimum and Maximum

May 1968

M. Leftin, S.M. Ostrow, and C. Preston

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Abstract: The preparation of world numerical maps of lower decile, median, and upper decile values of the monthly distributions of foEs for all 12 months of both a solar cycle minimum and a solar cycle maximum year is described. Tables of numerical maps of 4 representative months, March, June, September, and December, are given as examples of the complete set. Sample contour maps for these months are included to illustrate graphically the geographic, diurnal, seasonal, and solar cycle variation of lower decile, median, and upper decile foEs. No detailed instructions are given for using the maps, but a number of possible applications are indicated. The behavior of Es and problems of Es propagation are discussed, to indicate some limitations of the maps, and to call attention to additional data, such as Es reflection coefficients, needed to improve our knowledge of Es propagation and in particular to permit more accurate calculations of Es maximum usable frequency and transmission loss. The use of combinations of probabilities of both Es and regular layer propagation is recommended to provide improved estimates of actual propagation.

Keywords: Es, fbEs, foEs, FOT, high frequency radio propagation, ionospheric predictions, MUF, numerical maps, probability of propagation, sporadic E transmission loss

Disclaimer: Certain commercial equipment, components, and software are identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

For technical information concerning this report, contact:
Paul McKenna, Electronics Engineer
Institute for Telecommunication Sciences
Voice: (303) 497-3474 or (303) 497-5237
pmckenna@its.bldrdoc.gov

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