Ionospheric investigations using the sweep-frequency pulse technique at oblique incidence

Agy, Vaughn; Davies, K.

doi:10.6028/jres.063d.018

Cited by 8 publications

(9 citation statements)

References 11 publications

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“…Considerably more ambitious bistatic oblique sounding experiments than ours have been conducted [e.g., Wieder, 1955;Agy and Davies, 1959], and oblique sounding is at present routinely used for propagation path diagnosis [Fenwick, 1980]. The novelty of the present results lies mainly in the relative simplicity with which they were obtained, and the apparent adequacy of very simple mode identification methods.…”

Section: Discussionmentioning

confidence: 75%

First bistatic oblique‐incidence ionograms between digital ionosondes

Wright¹,

Kressman²

1983

Radio Science

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Identical digital ionosondes (dynasondes) at Brighton Colorado and at White Sands Missile Range, New Mexico, 864 km distant, were synchronized for bistatic sounding in multifrequency and fixed frequency recording patterns. Three propagation modes are observed, identified, and reconciled with standard propagation theory; these include one-hop propagation by sporadic E (Es) and the F region and two-hop (F-Es). Echo phase measurements at the four spaced antennas of the dynasonde receiving array permit echolocation calculations that are in good agreement with the path mid point, although effects of ionosopheric tilts and time variations are evident. These results encourage the concept of a global real time ionospheric monitoring network consisting of about 90 instruments that perform vertically incident and coordinated bistatic soundings, to yield a total of about 320 measurement 'locations.' Recently, consideration has been given to the practicality of global ionospheric monitoring by a thoughtfully deployed network of about 90 modern digital ionosondes [Wright and Paul, 1981]. An essential feature of that notion, by which an adequate spatial resolution is maintained despite this relatively small number (there are about 160 analog ionosondes operating today) is the use of more sophisticated instruments in both vertical and bistatic oblique measurement modes. The typical interstation distances in the network advocated are about 2500 km. Each station is the center of a ring of 5 or 6 others; with each proximate pair conducting bistatic soundings, about 260 additional measurement locations are obtained. We have therefore considered it useful to exploit the first practical opportunity to attempt bistatic soundings with a pair of digital ionosondes. Identical Dynasondes [Grubb, 1979], were established at NOAA's research site at Brighton, Col-

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Section: Discussionmentioning

confidence: 75%

First bistatic oblique‐incidence ionograms between digital ionosondes

Wright¹,

Kressman²

1983

Radio Science

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“…The backscatter sounding technique has been applied to study transequatorial propagation [Vil•ard et al, 1957], traveling disturbances [Valverde, 1958;Hunsucker .and Tv'eten, 1967], irregularities [Peterson et .al., 1955], and mode of propagation [Silberstein, 1958]. Some investigators have made the backscatter sweep in frequency [Sulzer, 1955;Agy ,and Davies, 1959]. The sweep-frequency backscatter sounder reveals the propagation modes very clearly.…”

Section: As Mentioned In Section D2 If the Loss Can Be Taken Into Acmentioning

confidence: 99%

Propagation and application of waves in the ionosphere

Yeh¹,

Liu²

1972

Reviews of Geophysics

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This review deals with the propagation of waves, especially radio waves in the ionosphere. In the macroscopic electromagnetic theory, the mathematical structure of wave propagation problems depends entirely on the properties of the dielectric operator in a magnetically nonpermeable medium. These properties can be deduced from general discussions of symmetry and considerations of physical principles. When the medium is specifically the ionosphere, various physical phenomena may occur. Because of a large number of parameters, it is desirable to define a parameter space. A point in the parameter space corresponds to a specific plasma. The parameter space is subdivided into regions whose boundaries correspond to conditions of resonance and cutoff. As the point crosses these boundaries, the refractive index surface transforms continuously. The medium in which the propagation takes place may influence the wave in many different ways. Specific experiments can be designed to probe the medium to learn its properties.

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“…Several authors (Wieder, 1955;Sulzer, 1955;Warren and Hagg, 1958;Agy and Davies, 1959;Aono, 1962) have used this method to determine the maximum usable frequency (MUF) from vertical ionograms. Comparing this value with the jm:tction frequency from ,…”

Section: Reduction Techntquementioning

confidence: 99%

Oblique Sweep‐Frequency Experiments Over a 2000‐km North‐South Subauroral Path

Möller¹

1967

Radio Science

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The high‐frequency limits for radio transmission are calculated from the data of vertical sounding stations. For distances < 2000 km, only the vertical data of the station at the midpoint of the path are used. To check this rule, oblique and vertical sweep‐frequency records which were observed under normal and anomalous conditions were compared. If the distribution of ionization is nearly constant along the route, normal conditions are present, and the high‐frequency limits calculated from the midpoint station are consistent with the oblique observations. Anomalous conditions are present during winter nights. At this time the critical frequencies may vary over a distance of 500 km by a factor of 2 or more. These steep gradients imply that the maximum observed frequency (MOF) is much higher than the calculated maximum usable frequency (MUF). Additional transmission modes are observed which are explained using rough models. The steep gradients were found to be moving southward during the night. A statistical analysis indicates that the magnitude of the gradient and the extent of this motion is increased with increased magnetic activity.

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Ionospheric investigations using the sweep-frequency pulse technique at oblique incidence

Cited by 8 publications

References 11 publications

First bistatic oblique‐incidence ionograms between digital ionosondes

First bistatic oblique‐incidence ionograms between digital ionosondes

Propagation and application of waves in the ionosphere

Oblique Sweep‐Frequency Experiments Over a 2000‐km North‐South Subauroral Path

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