The First Results of Ionospheric Skywave Propagation Experiment Over Taiwan

Abstract An ionospheric over‐the‐horizon propagation experiment was carried out in Taiwan to investigate characteristics of ionospheric F layer skywave propagation at frequencies 4–12 MHz. Experimental results show that there are prominent diurnal variations in the incident angle, virtual height and plasma frequency at reflection height, which are essentially regular and stable during daytime from 06 to 19 LT and random and irregular during nighttime from 23 to 05 LT. The peak‐to‐peak amplitude variations in the incident angles during daytime are in a range of 4°–5°, and those for virtual heights are 40–70 km. These parameters are validated by comparing true horizontal distance with those deduced from transmission curve equation, and the results show that mean relative errors are smaller than 0.8% and relative uncertainties are in a range of 1.17%–3.6%. One intriguing transient phenomenon occurring around sunrise is that virtual height and incident angle both change dramatically with respective peak descending rate of about 83 km/hr and maximum increasing rate of about 9°/hr is especially noted and discussed in this article. In addition to F layer propagation, the experimental results of the sporadic E (Es) layer propagation in Taiwan area is also shown and discussed.