Some Measurements of Short Wave Transmission

Quantitative data on field strength and telephonic intelligibility are given for transmission at frequencies between 2.7 mega-cycles (111 m.) and 18 megacycles (16 m.), and for distances up to 1,000 miles with some data at 3,400 miles. The data are presented in the form of curves and surfaces, the variables being time of day, frequency and distance. Comparisons are made between transmission over land and over water, between night effects and day effects, and between transmission from horizontal and from vertical antennas. Fading, speech quality and noise are discussed. The results are briefly interpreted in terms of current short wave theories.