  We consider heterotic string backgrounds in four-dimensional Minkowski space,
where N=1 supersymmetry is spontaneously broken at a low scale m_{3/2} by a
stringy Scherk-Schwarz mechanism. We review how the effective gauge couplings
at 1-loop may evade the "decompactification problem", namely the
proportionality of the gauge threshold corrections, with the large volume of
the compact space involved in the supersymmetry breaking.
