Influence of Fire Whirls on Radiowave Propagation

This paper presents the findings of an extensive measurement campaign conducted to assess the fire impact on signal propagation using a vortex generator. Pine needles and bushes were used as fuel, with approximately 4 kg of each material burned during the experiments. The ignition was initiated with a blowtorch, and the combustion process occurred in the presence of swirling wind to generated high and steady flames. Temperature and fuel mass consumption data were recorded, as well as the sparameters in both transmission and reflection modes. The perturbations introduced by fire were analysed from 600 MHz to 8 GHz, considering both frequency and spatial domain assessments. At specific frequencies, the magnitude of the frequency response exhibited varying levels of reduction across the band for different species. In the spatial domain, the amplitude reduction of the reflected component at the metallic wall reached up to 0.27 dB and 0.36 dB, for pine needles and bush tests, respectively.