Vertical and oblique ionospheric soundings over the long haul HF link between Antarctica and Spain

Abstract

This paper presents a comparative study between the oblique sounding results, the International Telecommunication Union Rec533 HF prediction model, and the vertical sounding results of a transequatorial long haul link. The long haul link is a 12,760 km link between the Spanish Antarctic Station, SAS, located in the Livingston Island and the Ebro Observatory (OE) in Spain. The data were collected during three consecutive surveys (/2012). The ionospheric channel from the SAS to the OE is studied in terms of frequency availability as function of time using the measurements of an oblique incidence sounder (OIS) and measurements of several vertical incidence sounding stations (VIS) placed near the estimated radiopropagation path. The results obtained show promising correlations between VIS and OIS measurements and led us to think that the frequency of largest availability for this particular long haul radio link can be estimated from the VIS sounding measurements. (2015), Vertical and oblique ionospheric soundings over the long haul HF link between Antarctica and Spain, Radio Sci., 50,[916][917][918][919][920][921][922][923][924][925][926][927][928][929][930]

Interannual Variation of a 12,760 km Transequatorial Ionospheric Channel Availability and Its Dependence on Ionization

“…Therefore, the higher frequency range have larger availability for day-time while lower frequency ranges behaves better for night-time in terms of channel availability. These results confirms the results pointed out in [10] and it extend to further surveys. In terms of variation of the FLA, it shows lower values for 2010-11 campaign, and it increases its maximums during the day (from 08 UTC to 17 UTC approximately) as we reach campaigns 2011-12, 2012-13 and finally, 2013-14, which presents the higher FLA values.…”

“…No tuners are needed for this antenna. These later upgrades and a complete description of the system can be found in better detail in [10,15]. …”

“…It also details the study of the narrowband-sounding performance using a monopole in transmission and the inverted-V antenna in the receiver; for information about the results of the narrowband sounding over the data received with the rugged monopole, see [10]. The interannual variation of the propagation parameters is evaluated taking into account different systematic measures from worldwide observatories in order to obtain relations between the solar activity phenomena and the channel availability of the ionospheric radio link.…”

“…Measures of channel performance and availability were retrieved for all the High Frequency (HF) transmited frequencies, from 2 to 30 MHz in steps of 500 kHz, at hourly samplings during the different Antarctic campaigns. Several studies have been conducted over the sounding data during the project as: (a) frequency/hour analysis of the oblique sounding results [8,9], (b) comparison with vertical sounding parameters [10] and (c) wideband measurements for communication purposes [7].…”

Physical Layer Definition for a Long-Haul HF Antarctica to Spain Radio Link

“…Just after that, we improved the sounding measurement in [11] with a new hardware platform (already described in Section 3) and obtained encouraging results in terms of Frequency of Largest Availability (FLA) and availability for all time of the day and frequency sweep. In this moment of the project, the sounding was already obtaining the required data in detail to define the best transmission frequency table once analyzed the FLA for each campaign [23] (see Figure 8 [24]). This led the system to settle a table of transmitting frequencies to test the performance of several modulation techniques.…”