Ultra-Short-Wave Propagation along the Curved Earth's Surface

The penetration of ultra-short-wave radiation beyond the range of optical sight is dependent on the diffraction and refraction of the rays. Proceeding from an analogy to optics the diffraction is calculated by various methods. It is found that calculation of the ray distribution beyond the line of sight yields the best agreement with measurement. The practical application of the results of calculation is represented by curves which give the decrease of field intensity with distance for various elevations in the whole range of wave lengths at present of interest. The curves are substantiated by airplane measurements. Measurements of the influence of refraction are appended.