Diversity Reception for Meteoric Communications
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One of the first goals of the research effort on meteoric communications was to establish the advantage, if any, of diversity reception. Three types of diversity were investigated: frequency, space, and polarization. Nearly perfect correlation of the signals was found for frequency diversity reception with a frequency separation of 4 kc and for space diversity reception for antenna spacings of up to 1200 feet, Only polarization diversity appears to provide any advantage. Two identical eight-element yagi receiving antennas were erected. one horizontally polarized and the other vertically polarized. The transmitting antenna was horizontally polarized. Analysis of the data shows that about 34 per cent of the signals on the vertical antenna equal or exceed in amplitude the signals on the horizontal antenna, but the shapes of the bursts on the two antennas are identical in most cases. It is concluded that there is not enough increase in system performance to justify the use of any of the three types of diversity.
[1] H. Staras. Diversity Reception with Correlated Signals , 1956 .
[2] J. Koch,et al. Factors Affecting Modulation Techniques for VHF Scatter Systems , 1959 .
[3] R. C. Kirby,et al. Radio Transmission at VHF by Scattering and Other Processes in the Lower Ionosphere , 1955, Proceedings of the IRE.