High Frequency spectrum: propagation, characterization, data communications and spectrum monitoring

Abstract

Recent natural disasters such as the Asian tsunami in 2004 and Jogjakarta earthquake in 2005 have proven the usefulness of HF communications in relief operations. With the destruction of existing communication infrastructure, HF communications systems and infrastructure can be set be set-up and operational with minimum time and cost. Long range communications is possible by the refraction of radio waves in the ionosphere. Despite the presence of satellite and optical communications, HF communications is still important to the military, law enforcement, search and rescue, relief organizations, amateur radio, shipping and diplomatic services. Besides voice and telegraphy, data communication services available include short messaging, email and telemetry. This paper provides an overview on HF propagation, channel characterization, adaptive data communications and spectrum monitoring. Preliminary results will be presented with the direction of research that will be pursued. The research outcomes will provide a better understanding on characteristics of the HF communications channel, and solutions for effective data communications and spectrum monitoring.