Azimuth spread of two‐hop ionospheric modes

Abstract

Abstract. We use direction finding ionogram data to analyze the azimuth spread of twohop F region modes in which ground scatter occurs (1) in the Gulf of Mexico and coastal areas of southern Louisiana and (2) in rough terrain in the Painted Desert region of Arizona. Ocean surface/coastal ground scatter are observed to be quasi-specular within the resolution of these measurements. Rough terrain ground scatter imposes a nominal 1.5 ø azimuth spread in addition to that introduced by the two traverses of the ionospheric F region.

Observations and Modeling of Traveling Ionospheric Disturbance Signatures From an Australian Network of Oblique Angle‐of‐Arrival Sounders

“…While there exist a number of commercially available vertical incidence sounders with an AoA and/or Doppler capability, for example, the Lowell Digisonde (Reinisch et al, 2009) and Dynasonde (Rietveld et al, 2008), such systems are not as common for one-way oblique incidence as they require comparatively large arrays. Many earlier oblique experiments (e.g., Rice, 1973;Sherrill & Smith, 1977;Sweeney, 1970) focused on AoA observations over narrow frequency channels only, although several more modern studies have collected oblique AoA soundings over the full HF band (e.g., Black et al, 1993;Rogers et al, 2003;Sherrill & Brown, 1997;Vertogradov et al, 2013;Wright & Kressman, 1983). For the ELOISE campaign, a new AoA sounding system was built using DST Group's direct-digital HF transmitter (DOTS) and receiver (DORS) designs, which employ a low-power (20 W) wideband chirp waveform to function as a high-fidelity OIS (Gardiner-Garden et al, 2008, 2011.…”