Studies of meteor propagation at 49 and 74 mc

Abstract

The characteristics of meteor propagation were investigated over two nearly parallel paths from Walpole, Mass., to Congaree, S. C. (1250 km) and from Walpole, Mass., to Smyrna, Ga. (1480 km). Simultaneous measurements were made at 49 Mc and 74 Mc. The duty cycle for meteor propagation was measured at both frequencies with separate determination of the contributions from underdense trails, specular overdense trails, and nonspecular trails. As a function of signal amplitude <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</tex> , the data could be fitted by assuming the duty cycle to be proportional to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A^{-k}</tex> , where <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</tex> lies between 0.9 and 1.8 depending on the time of day and types of trail contributing. Roughly half of the duty cycle came from nonspecular overdense trails and only 10 to 20 per cent from underdense trails. Simultaneous measurements with two separate receiving systems were made at both 49 Mc and 74 Mc in order to determine the effects of antenna height-difference and various lateral antenna-separations. The meteor signals were strongly decorrelated by certain antenna height-differences. Overdense trails produced some decorrelation with lateral antenna-separation, but underdense trails gave well-correlated echoes. No significant differences in meteor echo rate were found between receiving systems in very flat terrain at Congaree, S. C., and hilly terrain at Smyrna, Ga. For the hilly terrain, best signal correlation was found for nearby antennas which were at the same height above sea level.