MULTIFREQUENCY VARIATIONS OF THE WOLF-RAYET SYSTEM HD-193793 .2. OBSERVATIONS OF THE 1991-92 RADIO MAXIMUM

New observations of the colliding wind Wolf-Rayet WC7+04-5 binary HD 1 93793 (WR 140) at 6 cm and 21 cm with the Westerbork Synthesis Radio T elescope are presented. They show that the 21 cm flux, in particular; rose to a sharp maximum in 1992, fagging about a year behind the 6 cm flux. After maximum, both fell simultaneously The data are interpreted in terms of the varying circumstellar extinction to a non-thermal sou rce where the WC and O winds collide. The rising branch of the flux cu rve is determined mostly by extinction in the WC stellar wind and the fading branch mostly by that in the O star wind.