Using a wideband chirp sounder technique, the impulse response characteristics of a 500-km meteor burst channel were investigated for the purpose of studying the fine structure of meteor trails giving rise to multipath propagation, determining the channel delay spread statistics, and examining the correlation between multipath phenomena and meteor trail duration. To date, an analysis of these data has revealed that most of the time only a single dominant path exists between the transmitter and receiver. However, when multipath conditions are encountered, many paths varying in both strength and duration may exist and can adversely affect communications. Fortunately, multipath conditions were observed in only about 30% of all echoes and, while seen in both short- and long-duration trails, were found to occur most frequently during trails of longer temporal extent. In 90% of all measurements considered, the rms delay spread was found to be less than 100 ns. ¿ 1999 American Geophysical Union |