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Civilian handheld global positioning system receivers were tested for their susceptibility against radiated electromagnetic disturbances of different characteristics and field levels. This susceptibility data were compared to the existing electromagnetic compatibility (EMC) immunity requirements for electronic devices. Some of the receivers were disrupted by continues waves at in- as well as out-of-band frequencies, at field levels far below the existing EMC requirements. The possible reason for this is discussed. In general, due to the ever-growing use of commercial-off-the-shelf equipment even for critical functions, certificates of conformity to current EMC requirements may be inadequate. Index Terms--Global positioning system (GPS), high-power electromagnetic, high-power microwave, immunity, intentional electromagnetic interference (IEMI), ultra-wideband (UWB).

Image analysis of water drop patterns on an inclined flat polymeric insulator surface has been performed in order to find a simple mathematical function that indicates the level of hydrophobicity of the insulator surface. A simple function, given the acronym average of normalized entropies (ANE), seems to correlate well with hydrophobicity as defined by the Swedish Transmission Research Institute (STRI) hydrophobicity classification. It is a composition of three other functions, viz. the standard deviation, the Shannon information entropy and the `fraction of small differences'. All these are in turn based on the histogram of horizontal nearest-neighbor pixel differences for a given digital greyscale image of a water drop pattern. ANE is fairly independent of illumination intensity (exposure) as well as total gain and offset in a camera system (linear sensor). The experimental results also indicate that ANE is fairly independent of limited changes in the surface inclination, although this needs further investigation. Some of the various pitfalls associated with the photography of water drop patterns and processing Of images are identified, together with possible solutions for avoiding them.

This paper presents the experimental results on the induced common-mode (CM) voltages in a residential low-voltage power installation (LVPI) network exposed to electromagnetic fields from lightning. The objective of this investigation was to find out the severity of induced voltages in a low voltage network due to direct coupling of the lightning electromagnetic fields with the network in the absence of transient overvoltages coming through the distribution lines. Therefore, during the experiment the LVPI network was disconnected from the distribution network to exclude conducted transients in the measured signals entering through the mains. The induced CM voltages in a power outlet of the network were measured simultaneously with the vertical component of the electric field near the installation. The sequence of induced voltage events during the complete duration of one negative cloud-to-ground (CG) flash, one positive CG flash, and one cloud flash (CC), thought to be typical, is presented simultaneously with the electric field. It is shown that in addition to the return strokes in ground flashes, other discharge events taking place in the cloud; notably, the bipolar pulse trains associated with the initiation of both CG lightning and cloud lightning, are also important in determining the transient environment of electronic devices connected to a LVPI network. Flashes at a distance of about 25 km produced many induced-voltage pulses as large as 100 V, six such pulses in a time period of 0.4 ms in a negative CG flash, and 11 such pulses in a time period of 3 ms in a CC that immediately followed the ground flash. Index Terms - Electromagnetic coupling, lightning-induced voltages, low-voltage power installation