The influence of evaporation duct on the propagation of electromagnetic waves low above the sea surface at 3-94 GHz

From 23 September-13 November 1989 the member nations of the Propagation subgroup of NATO AC/243(Panel3/RSG.8) have conducted a propagation experiment near Lorient, France along a 27.7 km over-the-horizon path low above the sea surface. The aim of the trials was to investigate the influence of evaporation duct on the one-way low altitude propagation over sea and to validate available propagation models. Both path loss and meteorological data have been gathered continuously. It was the first time that this kind of experiment has been performed at seven frequencies (3, 5.6, 10.5, 16, 35, 36, 94 GHz) simultaneously during such a long time period (52 days). The paper describes only the results of the Netherlands contribution which comprised propagation measurements with sets at 5.6, 10.5, 16 (partly from NSWC USA), and 3 ad 94 GHz (both borrowed from NOSC USA)