Browsing by Author "Farley, D.T."
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Item Open Access Binary pulse compression techniques for MST radars(ICSU, International Council of Scientific Unions, 1984) Woodman Pollitt, Ronald Francisco; Sulzer, M.P.; Farley, D.T.In this paper we discuss many aspects of codes and decoding and their applications to MST experimenta. This includes Barker codes and longer individual codes, and then complementary codes and other code sets. We discuss software decoding and also hardware decoders and coherent integrators.Item Open Access Capabilities and limitations of the Jicamarca radar as an MST radar(ICSU, International Council of Scientific Unions, 1983) Woodman Pollitt, Ronald Francisco; Farley, D.T.The Jicamarca antenna is the largest radar antenna in the world. It is a flat and almost horizontal array of cross-dipoles, covering an area of 300 m by 300 m (9 Ha). It has a center frequency of 50 MHz with a bnndwidth of 1 MHz (determined by power combiners and splitters at the feed point of the antenna).Item Open Access Split-beam studies of the effect of electron collisions on ISR spectra near k ⊥ B(Instituto Geofísico del Perú, 2000) Farley, D.T.; Swartz, W.E.; Chau Chong Shing, Jorge Luis; Woodman Pollitt, Ronald FranciscoIn an effort to test these models, we divided the Jicamarca radar into two beams, each with half the power and half the antenna of the full system, and ran the standard double pulse Faraday/ ACF mode that gives ACFs in the F region. With split beams each beam has only one quarter of the signal-to-noise ratio of the full system, but it allows us to measure at two different aspect angles simultaneously. We have made comparisons between three pointing directions, which at an altitude of 400 km differ from normal to B by 4.8º, 3.4º, and 2.0°. (We compared 4.8 with 3.4 degrees and then with 2.0 degrees.) These angles ali vary slightly with altitude and are significantly smaller than they were when Jicamarca was built because of the slow change in the geomagnetic field. (These beam positions once were called the 6, 4.5, and 3 degree (on axis) positions.)Item Restricted The Condor Equatorial Spread F campaign:Overview and results of the large-scale measurements(American Geophysical Union, 1986-05) Kelley, M.C.; LaBelle, J.; Kudeki, E.; Fejer, B.G.; Basu, Sa.; Basu, Su; Baker, K.D.; Hanuise, C.; Argo, P.; Woodman Pollitt, Ronald Francisco; Swartz, W.E.; Farley, D.T.; Meriwether, J.W.During the Condor campaign a number of instruments were set up in Peru to support the rocket experiments. In this series of papers we report on the results of the experiments designed to study the equatorial F region. In this overview paper we summarize the main results as well as report upon the macroscopic developments of spread F as evidenced by data from backscatter radars, from scintillation observations, and from digital ionosonde meaurements. In this latter regard, we argue here that at least two factors other than the classical gravitational Rayleigh-Taylor plasma instability process must operate to yield the longest-scale horizontal organization of spread F structures. The horizontal scale typical of plume separation distances can be explained by invoking the effect of a shear in the plasma flow, although detailed comparison with theory seems to require shear frequencies a bit higher than observations indicate. On the other hand, the largest-scale organization or modulation of the scattering layer cannot be explained by the shear theory and must be due to local time variations in the ionospheric drift or to gravity wave induced vertical motions. Using simultaneous rocket and radar data, we were also able to confirm the oft quoted hypothesis that rapid overhead height variations in the scattering region over Jicamarca are primarily spatial structures advecting overhead. The detailed rocket-radar comparison verified several other earlier results and speculations, particularly those made in the PLUMEX experiments. In particular, companion papers discuss and extend some of the PLUMEX results to include the role of anomalous diffusion (LaBelle et al., this issue) in the theory of equatorial spread F and to shed light upon the shallow spectral form often observed in the intermediate-scale regime (LaBelle and Kelley, this issue).