In a previous article the authors presented the mathematical formulation of an original and general hysteretic operator for modelling force-deflection loops, in particular of isolators, the application being concerned by transient response. In the present article the dynamic behaviour of a dry-friction isolator is investigated using a steady-state experimental force-deflection loop to determine the parameters of the first order differential equation of the proposed hysteretic operator. Extracting the classical complex stiffness from the model and comparing it to measured value permits an initial validation. The harmonic response of a cantilever beam equipped with a dry-friction isolator is then predicted by coupling the classical second order equation of the beam in bending with the first order differential equation, giving the restoring force of the isolator. The experiment described permits validating the use of the proposed hysteretic model in the case of harmonic steady state behaviour.