The article is devoted to the organization of data transmission from seismic stations via radio channel. The analysis of noise and noise immunity of phase-locked frequency systems, as well as the effect of noise on the synchronization of signals over time, is carried out.

Keywords: earthquake, data transmission, synchronization, encoding, frequency, noise, interference, refraction, time

Article is devoted to the creation of direction finders for bearing earthquakes ionospheric precursors. Structural diagrams of two direction finders variants are given, their advantages and disadvantages are shown. Algorithms for the direction finders functioning and selection of ionospheric precursors are developed.

Keywords: radio direction finder, ionospheric earthquake precursor, signal selection, phased antenna array, wave, oscillation, phase, azimuth, angle of elevation