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. 13.62^oN and Long. 144.86^oE) 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 180^o  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.

Keywords

ionosphere, HF propagation, F2 layer, MUF, foF2