Accession Number:

AD0263899

Title:

THE INFLUENCE OF SOLAR DISTURBANCES ON VERY LOW FREQUENCY RADIO WAVE PROPAGATION OVER A LONG HIGH-LATITUDE PATH

Descriptive Note:

Corporate Author:

KIRUNA GEOPHYSICAL OBSERVATORY (SWEDEN)

Report Date:

1961-04-15

Pagination or Media Count:

1.0

Abstract:

AD-263 8999N5AD-263 900Div. 8, 25U TIPSPWH OTS price 2.60 Kiruna Geophysical Observatory Sweden. FADING RATE OF AURORAL REFLECTI N AT 92.8 Mcs, by Alv Egeland. 25 Apr 61, 29p. incl. illus. 17 refs. Scientific rept. no. 4 Contract AF 61052418 AFCRL-726Unclassified report DESCRIPTORS Aurorae, Electromagnetic wave reflections, Radio waves, Very high frequency, Atten ati n. 0 9statistical analysis, Statis tical functions, Wave analysis, Electromagnetic waves, Reflection, Correlation techniques. Wave transmission, Radio waves, Radio trans mitters, Amplitude modulation. Sweden. O PEN-ENDED Terms Rayleigh amplitude distribution. The frequency properties of 92.8 mc cw transmissions propagated via oblique auroral reflections were subjected to statistical analysis. The purpose was to determine the fading rate ofAURORAL REFLECTIONS AT 92.8 MC. Additional information was obtained concerning the random velocity of the auroral irregularities. The auroral fading records showed a Rayleigh amplitude distribution, i.e., the auroral echoes consisted of a large number of scattere wavelets and no major specularly reflected portion of the transmitter waves was received. The distribution of the difference between two consecutively sampled amplitude values fell fairly close to a Gaussian curve. Autocorrelation functions showed that signals often remained signi icantly correlated for about 0.005 sec, which points to substantial fading frequency up to about 200 c. In most of the 100 power spectra obtained, fading frequencies up to 300 or 400 c were found, but the power in the range of 0-100 c was clearly dominant. The root mean square value for the random velocity of the auroral irregularities, calculated from the autocorrelation functions of the amplitude, was found to vary between 100 and 220 ms. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE