|
AUTHOR(S): Fabián Rojas, Magda Vargas, Gerardo Guerra, Sergio Rivera
|
TITLE |
 PDF |
ABSTRACT The present work carries out the analysis in the frequency domain of the overlapping and attenuation of the amplitudes of the weighted power of the vocalizations of 24 bird species distributed in the American continent regarding the amplitudes of the audible noise emitted in 10 tower sites of 230 kV Transmission Lines (TL). The study compares noise measurements from 10 towers, selected according to their location conditions, for which audible noise measurements are made using LAeq and LAF50 weightings, and also a time domain recording of the noise emission was taken with a frequency band between 20 Hz and 20 kHz against 24 bird species’ vocalizations recordings. These species were selected by criteria of availability of their vocalizations in the HUMBOLDT Institute's repository, geographic location, and threat category, among others. The analysis shows a frequency band of species’ vocalizations whose significant power components start at 200 Hz and extend up to 11 kHz, while for the TL noise, the band starts at 0 Hz and extends up to 200 Hz. No significant interfaces or overlaps are found. Subsequently, a methodology for attenuation estimation is proposed based on the overlapping bands and the absolute amplitudes of the weighted powers adjusted to coincident frequency vectors. A component-by-component attenuation comparison is performed, and an attenuation index is calculated. The results for all vocalizations and all noise signals show a mean attenuation of less than 0.5% and attenuation values between 2.53% and 0.51% for quartiles 1 and 3 for the entire range of signals vocalization for all species. According to the results, it is unlikely that communication is being affected or that some type of mechanism associated with the TL noise is being generated in the species studied. |
KEYWORDS OHTL Noise, Birdlife, Bird vocalizations, Environmental impacts, Spectral analysis, Spatial discretization techniques, Short time Fourier transform, Spectrogram, Absolute signal power |
|
Cite this paper Fabián Rojas, Magda Vargas, Gerardo Guerra, Sergio Rivera. (2025) Bird vocalizations and audible Transmission Line (TL) noise: frequency overlap analysis for two 230 kV TLs. International Journal of Circuits and Electronics, 10, 30-45 |
|
