  We present results of new Chandra High-Energy Transmission Grating (HETG)
observations (2019 November - December) of the massive Wolf-Rayet (WR) binary
WR 48a. Analysis of these high-quality data showed that the spectral lines in
this massive binary are broadened (FWHM = 1400 km/s) and marginally blushifted
(~ -100 km/s). A direct modelling of these high-resolution spectra in the
framework of the standard colliding stellar wind (CSW) picture provided a very
good correspondence between the shape of the theoretical and observed spectra.
Also, the theoretical line profiles are in most cases an acceptable
representation of the observed ones. We applied the CSW model to the X-ray
spectra of WR 48a from previous observations: Chandra-HETG (2012 October) and
XMM-Newton (2008 January). From this expanded analysis, we find that the
observed X-ray emission from WR48a is variable on the long timescale (years)
and the same is valid for its intrinsic X-ray emission. This requires variable
mass-loss rates over the binary orbital period. The X-ray absorption (in excess
of that from the stellar winds in the binary) is variable as well. We note that
lower intrinsic X-ray emission is accompanied by higher X-ray absorption. A
qualitative explanation could be that the presence of clumpy and
non-spherically symmetric stellar winds may play a role.
