This paper describes the behavior of the simplified version of the radial differential mobility analyzer (DMA) Spectrometre de Mobilite Electrique Circulaire (SMEC) for different how conditions. The measured behavior is compared with the analytical description of Stolzenburg and Zhang and to the TSI-Short DMA which is designed to measure nano particles. The measurements show a good comparision for beta = 0.1 for an aerosol flow rate of Q(a) = 1.5 l/min and a sheath air flowrate of Q(sh) = 15 l/min.