  New time-resolved optical spectroscopic echelle observations of the nova-like
cataclysmic variable RW Sextantis were obtained, with the aim to study the
properties of emission features in the system. The profile of the H_alpha
emission line can be clearly divided into two (`narrow' and `wide') components.
Similar emission profiles are observed in another nova-like system,
1RXS~J064434.5+33445, for which we also reanalysed the spectral data and
redetermined the system parameters. The source of the `narrow', low-velocity
component is the irradiated face of the secondary star. We disentangled and
removed the `narrow' component from the H_alpha profile to study the origin and
structure of the region emitting the wide component. We found that the `wide'
component is not related to the white dwarf or the wind from the central part
of the accretion disc, but is emanated from the outer side of the disc.
Inspection of literature on similar systems indicates that this feature is
common for some other long-period nova-like variables. We propose that the
source of the `wide' component is an extended, low-velocity region in the
outskirts of the opposite side of the accretion disc, with respect to the
collision point of the accretion stream and the disc.
