  We study the phenomenological implications of effective supergravities based
on string vacua with spontaneously broken N=1 supersymmetry by dilaton and
moduli $F$-terms. We further require Minimal String Unification, namely that
large string threshold corrections ensure the correct unification of the gauge
couplings at the grand unification scale. The whole supersymmetric mass
spectrum turns out to be determined in terms of only two independent
parameters, the dilaton-moduli mixing angle and the gravitino mass. In
particular we discuss the region of the parameter space where at least one
superpartner is ``visible" at LEP2. We find that the most likely candidates are
the scalar partner of the right-handed electron and the lightest chargino, with
interesting correlations between their masses and with the mass of the lightest
higgs. We show how discovering SUSY particles at LEP2 might rather sharply
discriminate between scenarios with pure dilaton SUSY breaking and mixed
dilaton-moduli breaking.

High Energy Physics - Phenomenology