The Multiple Refraction and Reflection of Short Waves

This paper discusses the theory that normal long-distance short-wave communication is broaght about by a series of refractions and reflections. It shows how, if we know the "range/best wavelength" characteristic for ranges which entail only one "hop" of the rays, we can predict the best wavelength for any larger range necessitating a number of hops, it being assumed that propagation conditions, such as ionic distribution, remain the same throughout all those ranges. Single-hop characteristics given by the author in a previous paper are ased in this way to derive the characteristic for longer ranges in daylight. The result is in close accord with a curve given by Lloyd Espenschied which shows the result of actual experiment over long ranges. For conditions of darkness the present theory cannot be fully tested owing to incompleteness of the data over short ranges, but general agreement is indicated. It is shown that the theory helps to account for the phenomenon of "fading," and for dissimilarities in reception at stations situated a few miles apart, but both receiving from the same sending station. Suggestions are made as to future research. It is thought that multiple refraction and reflection is the most satisfactory explanation of the effects met with in the course of ordinary short-wave communication at long ranges.