Tropospheric communication in arid zone with space diversity

Describes the results of a series of experiments conducted on a 158 Km path between IIT Delhi and CEERI Pilani. Most of the path towards the Pilani side is almost desert while it is rocky and inhabited towards the Delhi end and can be broadly classified as a mix desert and continental subtropical climate path. The system operates in 4.4 GHz to 5 GHz band, and has the capability of two way communication in a full duplex mode. Each terminal has two transmitters with two power amplifiers capable of 1 kW output. The receiver utilizes a parametric amplifier with a noise figure of 4 dB. Dual polarized parabolic antennas of 3.05 m diameter are used. One of the most efficient and widely used protection against the effect of multipath, is the space diversity technique. This technique takes advantages of the decorrelation between the received signals by two separate antennas. The separation between two antennas can be varied between 45 and 100 wavelengths. Results based on long term experiments provide a better understanding of the behaviour of a space diversity reception. The fading distribution, the fade depth and the degree of correlation between fading over two horizontally spaced antennas, when the link is in an arid zone, appear to follow the known general trends.<
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