Super strength signalling in marine and coastal regions

A particular window of time when mobile signals and radio waves are ‘super strength’ — allowing them to be clearer and travel greater distances — has been discovered by Salil Gunashekar as part of his doctoral studies at the University of Leicester’s Department of Engineering in England.

The research, examining the signal strength of radio waves travelling over the sea, identified late afternoons and early evenings in spring and summer as a time when enhanced signals occur.

The research has implications for the design of mobile phone networks operating in marine and coastal regions.

“When radio waves travel for long distances over the sea their strength can be affected by the weather. The constantly changing weather conditions over the sea mean that marine and coastal environments, in particular, are prone to unusual atmospheric phenomena that enable radio waves to travel longer distances and have higher strengths than expected,” said Gunashekar, who is now a post-doctoral research associate in the Radio Systems Research Group.

During his PhD research, Gunashekar conducted a detailed theoretical and experimental investigation of the propagation characteristics of over-sea radio communications.

Specifically, he found that between August 2003 and August 2005, three long-range radio paths operating at a frequency in the UHF band at 2 GHz were established in the British Channel Islands.

This frequency is used by many mobile phones. The relationship between specific over-sea propagation mechanisms and signal strength distribution patterns in a temperate region such as the English Channel have been examined, modelled and correlated with meteorological parameters.

“Interestingly, signal strength enhancements have been observed on all three radio paths, predominantly in the late afternoon and evening periods, in the spring and summer months. During these periods, which occur only 5-10% of the time, the influence of higher-altitude radio wave ‘trapping’ structures has been verified,” Gunashekar said.

The research conducted in this investigation is expected to have implications for the design of mobile phone networks operating in marine and coastal regions, as well as other maritime communication systems such as those used in commercial shipping and sea-rescue operations.