Accession Number : AD0779959

Title :   Intermediate and Short Distance Sky-Wave Propagation Charts. Volume I. Africa I. January-December.


Report Date : 15 OCT 1971

Pagination or Media Count : 186

Abstract : The report is one volume in a set known as the Intermediate and Short Distance Sky-Wave Propagation Charts for Africa (Short Title: ISD Book). There are 31 separate volumes--one for each of the areas of the world shown on the map on page xiii of any volume. These charts show the upper and lower limiting frequencies for radio communication in the 2 to 30 MHz band for distances up to 2400 km. Predicted values of frequencies are shown for the solar activity extremes for a normal solar cycle; i.e., sunspot numbers of 10 and 110. Values of frequency predictions may be obtained for any time during the normal solar cycle by means of interpolation. These charts will be applicable at least through calendar-year 1976. Within each volume, the predictions are given for six seasonal intervals--January-February, March-April, May-June, July-August, September-October, and November-December. Within each seasonal interval, the predictions are given in a series of 22 charts. The first chart provides Maximum usable frequency (MUF) and optimum traffic frequency (FOT) values for each hour. The other 21 charts provide lowest useful high frequency (LUF) value at even two-hour intervals. (Author)

Descriptors :   *Ionospheric propagation, *Africa, Radio waves, Communication and radio systems, High frequency, Electromagnetic radiation, Charts, Optimization, Time, Predictions, Sunspots, Solar activity, Solar cycle, Ionospheric disturbances, Seasonal variations

Subject Categories : Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE