Vertical and oblique ionospheric soundings performance comparison over the 12,760 km transequatorial HF link between Antarctica and Spain

This paper presents the second part of the study of the oblique sounding of a 12,760 km transequatorial ionospheric link between Livingston Island (Antarctica) and Cambrils in Spain. The study consists of the comparison among the oblique sounding results using an inverted V as receiver antenna, the International Telecommunication Union Rec533 HF prediction model, and the vertical sounding results on the path of the long haul channel. The data were collected the last consecutive surveys, when the inverted V antenna was operative (2010–2011, 2011–2012, 2012–2013, and 2013–2014). The ionospheric channel is studied in terms of frequency availability depending on time using the measurements of an oblique incidence sounder (OIS) and also measurements of several vertical incidence sounding stations (VIS) on the path of the long haul channel. The results obtained show similarities between the VIS and the OIS measurements; following previous studies preliminary results, the experiments conducted led us to think that the frequency of large availability can be estimated depending on the VIS sounding results.