The interannual modulation of the geomagnetic activity caused by solar activity is investigated by means of the mutual spectral analysis. The frequency characteristics of connection between the Wolf numbers W 0 and the aa index of geomagnetic activity for the time interval 1890-1990 are analysed. Interannual and seasonal variations in the corresponding coherence spectra CH(T ) for the quasi-decennial, quasi-pentennial, quasi-triennial and quasi-biennial cycles are revealed. The particular properties of the mean parameters for individual months are outlined.