HF Propagation during geomagnetic storms at a low latitude station

Abstract

The variations in the ionosphere affect the radio wave propagation. These variations become more pronounced as a result of geomagnetic storms. The data from a Digitonide installed at Guam station (Lat. 13.62oN and Long. 144.86oE) during geomagnetic events was scaled for an ionogram, which shows the heights of different layers in the ionosphere at different frequencies. The ionogram was then analysed and interpreted. Results showed that virtual heights steadily increased as frequency increased. The splitting of waves into ordinary and extraordinary waves as they enter the ionosphere was an indication that waves divide on entering the ionosphere. The extraordinary was consistently higher than the ordinary wave. The highest frequency the ionosphere above the station could refract signal at 180o was 12.625 MHz. This is the frequency at which communication was to be made from one location to another location within the location of the station. Comparative results between the iongrams of disturbed and undisturbed ionosphere showed that geomagnetic storms lead to increased foF2, MUF values and NmF2. The results also revealed that the strength of the refracted signals were particularly good, strong enough to rebound from the earth and refract again.