Title :
Anomalous ground wave TILT measured over WET ground
Author_Institution :
Underhill Res. Ltd., Lingfield, UK
Abstract :
The nominally vertical E-field of a ground wave is classically predicted to tilt forward in the direction of wave travel. Past measurements confirming this have been made at four spot frequencies between 5.25 and 28MHz by NTIA in Boulder, Colorado, USA reported in 1984. The ellipticity of the wave motion was also measured. A novel tuned loop based wave tilt equipment has been devised to make measurements of both tilt and wave ellipticity over wet clay soil at any frequency down to 2MHz. Below about 5.3MHz the direction of wave tilt has been found to reverse to a backward tilt and become `anomalous´. New EM theory is presented to explain this fundamentally new discovery.
Keywords :
electromagnetic field theory; radiowave propagation; tropospheric electromagnetic wave propagation; EM theory; backward tilt; frequency 5.25 MHz to 28 MHz; ground wave tilt; tuned loop based wave tilt equipment; vertical E-field; wave motion ellipticity; wet ground; Wave-tilt; ground-wave; tuned-loop nulling;
Conference_Titel :
Ionospheric Radio Systems and Techniques (IRST 2012), 12th IET International Conference on
Conference_Location :
York
Electronic_ISBN :
978-1-84919-623-9
DOI :
10.1049/cp.2012.0397