Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 28.

Thesis (M.S.)--Colorado State University, 1978. / Includes bibliographical references (leaves 76-79). Also available in print version.

Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin, 1960. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 30).

Proper radio link design requires an accurate prediction of the effective earth radius factor (the kfactor) distribution, for the location where propagation is intended. Though a median value of k equals 4/3 is normally use for communication design purposes, in reality the true k-factor values differ, for different locations, globally. The effective earth radius factor distribution for Southern Africa was evaluated in the dissertation. The two Southern African countries chosen for the study are Botswana and Republic of South Africa. The dissertation reports in detail a study on the topic using three years radiosonde data obtain in Maun, Botswana and ten months radiosonde data collected in Durban, South Africa. An analytical model was proposed, which predicts the probability density function of the k-factor for the Southern Africa using the data from these two countries. Also a comparison of the data from the two countries was done in the analysis and reported in the write-up. The application ofthe work was also investigated and reported by simulating a radio link between Sherwood and Umlazi in Kwazulu-Natal Province of South Africa. The consequence of using inappropriate design value of k on link reliability was also investigated and reported. Recommendation for future work was given in the concluding chapter for future improvement on the study. Radio communication designers will find the results obtain in the report useful. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2005.

Thesis (M.S. in Systems Engineering (Electronic Warfare))--Naval Postgraduate School, September 1990. / Thesis Advisor(s): Davidson, Kenneth L. Second Reader: Hershey, Scott H. "September 1990." Description based on title screen as viewed on December 29, 2009. Author(s) subject terms: Retractive conditions, prongation, Central America, radar, microwave. Includes bibliographical references (p. 60-61). Also available in print.

[pt] O crescimento da demanda por serviços de telecomunicações em terra firme também pode ser encontrado em ambientes marítimos por usuários a bordo de embarcações, sejam elas civis ou militares. Nestes ambientes, um fenômeno conhecido como duto de evaporação influencia a propagação eletromagnética na troposfera, proporcionando a comunicação ponto-a-ponto em distâncias além do horizonte rádio. Este trabalho utiliza a técnica de traçado de raios para analisar o comportamento da onda eletromagnética nestes meios. Foi elaborado um algoritmo capaz de traçar raios e determinar amplitudes e fases do campo elétrico em meios inomogêneos bidimensionais dado um mapa de refratividade modificada M. A partir destes mapas, o algoritmo calcula os gradientes verticais de M, que podem variar ao longo do percurso, e traça os raios, a partir da antena transmissora. Como aplicação, além de cenários com dutos de evaporação, foram utilizados mapas de M estimados com base em dados meteorológicos fornecidos por radiossondas lançadas no litoral brasileiro. Os resultados obtidos foram comparados aos fornecidos pelo software Advanced Refractive Effects Prediction System (AREPS), baseado na solução numérica de equação parabólica. Este trabalho também apresenta resultados estatísticos de dutos de evaporação no litoral brasileiro, a partir de dados meteorológicos fornecidos por boias oceanográficas do Programa Nacional de Boias (PNBOIA). Para tal, é utilizado, com pequenas alterações, o algoritmo de Paulus-Jeske, que estima a altura de dutos de evaporação. / [en] The demand growth for land-based telecommunications services can also be found in maritime environments by users on board ships, whether civilian or military. In these environments, a phenomenon known as the evaporation duct influences electromagnetic propagation in the troposphere, providing point-to-point communication at distances beyond the radio horizon. This work uses the raytracing technique to analyze the behavior of electromagnetic waves in these media. An algorithm capable of tracing rays and determining electric field amplitudes and phases in two-dimensional inhomogeneous media was developed, given a map of modified refractivity M. From these maps, the algorithm calculates the vertical gradients of M, which can vary along the path, and traces rays from the transmitting antenna. As an application, in addition to scenarios with evaporation ducts, M maps were estimated based on meteorological data provided by radiosondes launched in the Brazilian coast. The results obtained were compared with those provided by the Advanced Refractive Effects Prediction System (AREPS) software, based on the numerical solution of parabolic equation. This work also presents statistical results of evaporation ducts in the Brazilian coast, based on meteorological data provided by oceanographic buoys of Programa Nacional de Boias (PNBOIA). For this, the Paulus-Jeske algorithm, which estimates the height of the evaporation ducts, is used with small changes.

Water vapour is the principle source of opacity at infrared wavelengths in the Earth’s atmosphere. In support of site testing for the European Extremely Large Telescope (E-ELT), we have used La Silla and Paranal as calibration sites to verify satellite measurements of precipitable water vapour (PWV). We reconstructed the PWV history over both sites by analysing thousands of archived high-resolution echelle calibration spectra and compared that to satellite estimates for the same period. Three PWV measurement campaigns were conducted over both sites using several independent measurement techniques. Radiosondes were launched to coincide with satellite measurements and provide a PWV reference standard allowing intercomparison between the various instruments and methods. This multi-faceted approach has resulted in a unique data set. Integral to this analysis is the internal consistency provided by using a common atmospheric model. / xvii, 206 leaves : ill. (some col.) ; 28 cm