A study on the effect of building on the HF direction finding
The effect of new building on the high-frequency (HF) direction finding (DF) is analyzed. Commercially available software is used to get array manifold of the HF DF system taking the effect of the new building into account. The terrain, building and the array antenna system are modeled. The new building near the antenna system is also modeled to see whether it actually has an effect on the performance of the DF system. Interferometer DF algorithms has been employed.
Dielectric material modeling in the MoM-based code FEKO
The majority of structures of electromagnetic interest contain regions of non-metallic materials. The applicability of a numerical analysis tool is greatly reduced by an incapability or limitation in treating dielectric regions. The treatment of propagation medium properties is inherent in the formulation of field-based analysis tools. In the method of moments (MoM), dielectric regions require extended formulations and additional resources to model. A number of techniques for the optimum representation of these regions has been implemented in FEKO, a commercial MoM-based analysis tool. Each of the available techniques within the MoM have certain applications to which they are better suited. The optimum technique to use is often immediately evident to the inexperienced user. This paper briefly introduces each of the available techniques, and then demonstrate, by way of an example, how the choice of technique can influence the efficiency and accuracy of simulation.
Accurate measurements of output characteristics and detonations of motorbike high-speed racing engine and their optimization at actual atmospheric conditions and combusted mixture composition
Abstract At a motorbike high speed racing engine there is very important an output engine characteristics which depends significantly on a detonation combustion rate, atmospheric conditions and a combusted mixture composition. The combustion process has got a relevant influence on a wear degree of main engine parts or on their damage eventually. The detonation combustion rate is very important because this kind of burning can be not only destructive but a useful phenomenon, as well. If the process of detonation burning is kept on a certain level, it can help significantly to the next increasing of an engine power output. In this article there is described the measurements of output characteristics of a high-speed racing engine which were performed by means of a data-recording system and the detonation combustion was evaluated using a quantitative method. The actual values of atmospheric conditions and the mixture composition were added to the measured values. Then the obtained values are compared visually with a damage degree of an engine piston caused by the detonation burning. The result is a limit value expressed in a number of detonation units related to a run distance interval of the vehicle driven by the high-speed racing engine. In framework of this run distance interval there is the process of detonation burning profitable. As well as it increases an engine power output and together it is not destructive with regard to engine design parts.