Characteristics of Ionospheric E_s Propagation and Calculation of E_s Signal Strength

Abstract

This report begins by describing the distribution of reflection points in the ionospheric E propagation as observed in the Far East. The ionospheric attenuation of theE, signal is statistically treated as a function of a ratio of the frequency used to the critical frequency, foE,, at the path midpoint;and its distance dependence is compared with the so-called secant law. The attenuation of two-hop

Consolidated Amateur Radio Signal Reports as Indicators of Intense Sporadic E Layers

“…Across the whole series, good correspondence can be seen between the locations of the concentrations of great circle path midpoints and the nearby ionosonde ftEs values. Precise and detailed correspondence should not be expected, because the ftEs figures represent snapshots at the middle of each period, the intense Es clouds are likely to be small, and the derived reflection points can only be approximations because of the possibility of off-axis paths [42]. Nonetheless, the structure and evolution of the event can clearly be seen.…”

Rapid and Accurate Measurement of Polarization and Fading of Weak VHF Signals Obliquely Reflected From Sporadic-E Layers

“…The mechanism for the oblique reflection of radio waves from Es layers is not well understood, with candidates including specular reflection [11], [12], [45], scattering [11], [12], and magneto-ionic double refraction [13]. Magneto-ionic double refraction in the ionosphere, whereby a wave launched vertically is split into two circularly polarized waves which travel at different speeds and, therefore, exhibit different time delays on reflection back to ground, was first observed in the 1930s [1].…”

“…On that basis, but taking account of the fact that the antennas are of identical materials and construction (the principal sources of modeling errors), the characteristics of the two antennas are estimated to differ by less than 0.7 dB and 5 • . 6) Antenna off-axis bias: NEC-4 modeling indicates that signal deviations off-axis, due either to errors in antenna pointing or to Es reflection via indirect paths [45], could cause additional biases of up to 1 dB in gain and up to 2 • in phase for a 15 • azimuth deviation from the true direction to the beacon. 7) Ground reflection bias: due to Es reflection height uncertainty, a range of possible elevation angles must be considered.…”

Statistical modelling of radio wave propagation under sporadic E-Layer influence

“…Seasonal maps of probability of sporadic E occurrence at foEs >7 MHz for four regions (the Europe and Northern Africa, Northern America, Far East, and other regions) are calculated by Smith (1978). For estimation of probability of a radio communication through sporadic ELayer in VHF-band the Japanese researchers offered a set of curves of foEs distribution and a set of daily foEs variations, observed with various probability for various regions of globe: the Europe and Northern Africa (region A), Northern America (region B), and Far East (region C) (Miya and Sasaki, 1966). This technique subsequently after numerous improvements had been accepted by CCIR (1978CCIR ( -1990.…”