Accession Number : AD0780552

Title :   The Angular Distribution of Spread-F Returns from an Artificially Modified Ionosphere.

Descriptive Note : Final technical rept. Jan 73-Feb 74,

Corporate Author : RAYTHEON CO SUDBURY MASS

Personal Author(s) : Allen,E. M. ; Thome,G. D. ; Rao,P. B. ; St. Germain,R. L.

Report Date : FEB 1974

Pagination or Media Count : 40

Abstract : A 32 element HF phased array has been used to study the angular spectrum of spread-F returns from an ionosphere modified by the powerful radio frequency heater transmitter at Platteville, Colorado. The diagnostic radar is a coherent pulse system which provides an angular resolution of 2.7 degrees in azimuth and elevation at the midband frequency of 7.5 MHz, a range resolution of 30 Km, and a Doppler resolution of 0.08 Hz. The results are presented in the form of sky maps (brightness versus azimuth and elevation) of the returns as a function of group delay Doppler shift, polarization, and sounding frequency. The principal result is that the returns which suffer the greatest group delay at a given sounding frequency come from a direction looking up the earth's magnetic field and exhibit negative Doppler shift. (Modified author abstract)

Descriptors :   *Ionospheric modification, *Heating, Ionospheric propagation, High frequency, Electromagnetic wave reflections, Ionospheric disturbances

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE