Measurement of narrow pulse distortion over a short HF skywave link: Es and F2 summer results
Article first published online: 7 DEC 2012
Copyright 1989 by the American Geophysical Union.
Volume 24, Issue 4, pages 585–597, July-August 1989
How to Cite
1989), Measurement of narrow pulse distortion over a short HF skywave link: Es and F2 summer results, Radio Sci., 24(4), 585–597, doi:10.1029/RS024i004p00585.(
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 6 MAR 1989
- Manuscript Received: 12 AUG 1988
A high resolution frequency modulated, continuous wave (FMCW) oblique incidence sounder was used in an experiment to measure the minimum pulse width that could be transmitted via a one-hop F2 layer and Es propagated ionospheric paths. Measurements were made over a 234-km link in the United Kingdom by using 3 MHz frequency sweeps at 1 MHz/s sweep rate and repeated at 10-s intervals for 10 min. The collected data were weighted and spectrum analyzed via the fast Fourier transform (FFT) algorithm to a 8–13 μs time resolution. This permitted the resolution of the different multipath components including the magnetoionic waves. Narrow pulse distortion, and consequently the instantaneous bandwidth, was estimated by evaluating the 6-dB width of the compressed pulses and the slope of the group time delay versus frequency of the Es and one-hop F2 ordinary and extraordinary waves. The time history of the different modes was obtained by analyzing repetitive sweeps.The results indicated that the sporadic E layer introduced less distortion and was more stable with time than the F2 layer. Moreover, the slope of the group time delay with frequency was often found to give a more accurate estimate of the dispersion suffered by narrow pulses than the 6-dB width determined by Fourier transforming the FMCW data.