Tropospheric effects on microwave propagation in hilly terrains

The authors deal with the propagation characteristics observed over a long hop line-of-sight microwave link. An attempt is made for the first time in India to study systematically the fading observed over this long hop, hilly terrain, microwave links´ and also to suggest some remedial measures. Correlation studies made with the help of radiosonde data and sodar observations indicate that the observed fading is mostly due to the super-refractive conditions prevailing in the 200 to 300 m region above the surface leading to multipath fading. The upward tilting of antennas in the convective environment for improvement of the system performance has been suggested