Amplitude and frequency variations of HF signals propagated over high latitude paths

The high latitude ionosphere forms a highly dynamic and disturbed medium which can severely affect HF radio signals propagating through these regions. In order to investigate the characteristics of this type of propagation, a frequency agile transmitter has been installed north of the auroral oval, well within the polar cap region. Several receiving and data logging systems were deployed at various sites to provide a variety of trans-auroral oval paths together with one path contained entirely within the polar cap region. Several-one-month experimental campaigns have been conducted at different times of year. Results obtained from measurements undertaken during two of these periods (18 July-11 August 1988 and 16 January-11 February 1989) are presented