August 1970 | NTIA Technical Memo 243

A numerical method for predicting the Fl-Iayer critical frequency

D. H. Zacharisen; Rayner K. Rosich; G. R. Enoch

Abstract: The Fl layer is not explicitly included in current ITS high frequency radio propagation predictions. Numerical maps of Fl layer characteristics, similar to those for F2, E, and Es characteristics now in use, were rejected in favor of a more concise representation by a formula expressing the strong dependence of monthly median foFI on the sun's zenith angle. Three formulas for predicting monthly median foFI were tested against 8 months of monthly median foFl data observed in 1958 and 1964, years of maximum and minimum, respectively, of the solar cycle. The root mean square residuals between observed data and predictions from the three formulas were compared. Recommendations are made for deriving an improved formula.

To request a reprint of this report, contact:

Lilli Segre, Publications Officer
Institute for Telecommunication Sciences
(303) 497-3572

Disclaimer: Certain commercial equipment, components, and software may be 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.

Back to Search Results