On the possibility that sporadic E ionization is a source for certain scintillation disturbances in the UHF channels of FLEETSATCOM

The concept of wedge refraction is discussed and calculations of the amounts of refractive bending for possible models of sporadic E patches are presented. A general concept is developed but emphasis is placed upon possible effects at 250 MHz. For certain conditions, sporadic E patches may produce measurable fading effects observable at a ground terminal receiving UHF transmissions from a synchronous satellite. It is tentatively concluded that these phenomena will be most evident at mid-latitudes during summer daytime conditions. Single patches will produce quasi-periodic disturbances at each edge lasting the order of a minute, while, multiple patches will increase the disturbance duration. Noise-like disturbances will be produced for nonuniform wedges or wedge super-position. Predictions of E sub s scintillation effects of FLEETSATCOM are no better than the prediction of E sub s patches which is obviously poor from a deterministic point of view. Only statistical information based upon archival data is available. Use of the vertical incidence ionosonde at Wallops Island, Virginia is suggested for extracting real-time assessment of the E sub s scintillation possibility at NAVCOMSTA, Norfolk.