Václav Kvicera

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The wavelength dependence of the extinction coefficient in fog and haze is investigated using Mie single scattering theory. It is shown that the effective radius of drop size distribution determines the slope of the log-log dependence of the extinction on wavelengths in the interval between 0.2 and 2 microns. The relation between the atmospheric visibility(More)
Results on a propagation study carried out on a free space optical link at 850 nm on an 850 m long path over a one-year period are given. All recorded individual attenuation events were compared with the concurrent meteorological conditions and were identified according to the types of individual hydrometeors. Cumulative distributions of attenuation due to(More)
Fog is the most important impairment factor for free space optical links. The detailed data about fog characteristics are very rare. Therefore, fog visibility data obtained at airports are also processed. The characteristics of fog events obtained at the Prague-Ruzyne airport in the Czech Republic over a 13-year period are given. These characteristics were(More)
The BER and the availability belong among the basic qualitative parameters of free space optical (FSO) links. The BER parameter is usually mentioned by FSO manufacturers, but it is not defined what conditions a certain value of BER stands for. This article deals with problems of measuring the BER of free space optical link and with questions how to(More)
Electromagnetic wave propagation research in frequency band 58GHzwas started at TESTCOM in Praha due to lack of experimentally obtained results needed for a realistic calculation of quality and availability of point-to-point fixed systems. Rain attenuation data obtained from a path at 58GHz with V polarization located in Praha was processed over a 5-year(More)
Simultaneous measurements of the liquid water content (LWC) and optical attenuation have been analyzed to predict optical attenuation caused by fog particles. Attenuation has been measured at two different wavelengths, 830 nm and 1550 nm, across co-located links. Five months measured data have been processed to assess power-law empirical models, which(More)
Long-term statistics of hydrometeor attenuation obtained on two experimental parallel terrestrial paths at 58 GHz and 93 GHz with the same path length of 850 m are presented. The statistics of rain attenuation obtained are used for the frequency scaling. Several methods are tested and the results obtained are discussed.