We present new radio and optical observations of the colliding-wind system
WR 146 aimed at understanding the nature of the companion to the Wolf-Rayet
(WR) star and the collision of their winds. The radio observations reveal
emission from three components: the WR stellar wind, the non-thermal wind-w
ind interaction region and, for the first time, the stellar wind of the OB
companion. This provides the unique possibility of determining the mass-los
s rate and terminal wind velocity ratios of the two winds, independent of d
istance. Respectively, these ratios are 0.20 +/- 0.06 and 0.56 +/- 0.17 for
the OB-companion star relative to the WR star. A new optical spectrum indi
cates that the system is more luminous than had been believed previously. W
e deduce that the 'companion' cannot be a single, low-luminosity O8 star as
suggested previously, but is either a high-luminosity O8 star, or possibly
an O8+WC binary system.