Variation of Ionospheric Narrowband and Wideband Performance for a 12,760 km Transequatorial Link and Its Dependence on Solar and Ionospheric Activity

The ionosphere provides a channel that is able to propagate electromagnetic waves for long-haul communications, allowing Non-Line-Of-Sight (NLOS) radio communications in the high-frequency band (HF). Nonetheless, its performance as a communications channel mainly depends on solar activity, as Earth’s diurnal and seasonal cycles modify the ionospheric ionization by the sun and consequently the channel performance. La Salle and the Observatori de l’Ebre have conducted oblique soundings of a 12,760 km ionospheric channel from Livingston Island (South Shetland Archipelago—Antarctica −62.7∘S, 299.6∘E) to Cambrils (Spain −41.0∘N, 1.0∘E) to evaluate this evidence and analyze the characteristics of this particular channel. The final goal of the project is to establish a stable communications link to be used as a backup for low throughput data transmission from the various geomagnetic and meteorological sensors located in the Spanish Antarctic Station. The aim of this paper is to confirm the relationship between the channel availability of narrowband and wideband communications and the resulting channel parameters with the solar and ionospheric activity for four consecutive sounding campaigns.