Long term variability of radiosources in the frequencies of 22 GHz and 44 GHz.

The radio sources 3C273, OV236, Cen A and Sgr A were observed during a period of six years (1980 - 1986) in the frequencies of 22 GHz and 44 GHz. All of them presented some variability, specially the quasar 3C273, which after a period of intense activity (1981 - 1985), returned to its quiescent level at the end of 1985. The increase of the flux density in these frequencies is associated to the ejection of new components by the central source in the quasar, as observed in the maps obtained by VLBI techniques.