Extremely low frequency electromagnetic waves (ELF; here from 0.03 to 1000 Hz) propagating in the spherical resonant cavity between the Earth's surface and the ionosphere provide an effective means of testing the ionosphere's state and its inhomogeneities. They allow for the analysis of solar activity impacts in the UV and X-ray range, solar flares, and space weather. Additionally, they enable studies of such terrestrial phenomena of importance as climate change. Analysis of ELF waves is also crucial for mitigating possible coherent electromagnetic interference in gravitational wave detector networks, like LIGO-VIRGO-KAGRA. Our new measurements from the ELA11 station in the Bieszczady Mountains offer promising potential for advancing such research. Here, we present the first in a series of studies conducted over the past year based on data from this station. More...