We study the Mount Wilson indices we obtained indirectly from IUE high and
low 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 to
1996. We analyze the activity signatures, which correspond to the primary star,
with the Lomb-Scargle periodogram. From the analysis of V711 Tau data, we found
a possible chromospheric cycle with a period of 18 years and a shorter near
3-year cycle, which could be associated to a chromospheric flip-flop cycle. The
data of II Peg also suggest a chromospheric cycle of near 21 years and a
flip-flop cycle of 9 years approximately. Finally, we obtained a possible
chromospheric cycle of near 6 years for UX Ari.Comment: 4 pages, to appear in proceedings of Cool Stars 1
