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We study the Mount Wilson indices we obtained indirectly from IUE high andlow resolution spectra of the RS CVn-type systems II Peg (K2IV), UX Ari(K0IV+G5V) and V711 Tau (K1IV+G5V), extensively observed by IUE from 1978 to1996. We analyze the activity signatures, which correspond to the primary star,with the Lomb-Scargle periodogram. From the analysis of V711 Tau data, we founda possible chromospheric cycle with a period of 18 years and a shorter near3-year cycle, which could be associated to a chromospheric flip-flop cycle. Thedata of II Peg also suggest a chromospheric cycle of near 21 years and aflip-flop cycle of 9 years approximately. Finally, we obtained a possiblechromospheric cycle of near 6 years for UX Ari.

Possible chromospheric activity cycles in II Peg, UX Ari and V711 Tau