A multifrequency pulse radar reflectometer (PRR) has been designed, commissioned, and is operating successfully on the small tight aspect ratio tokamak (START). The data obtained with this technique allow the study of the density profile evolution during the shot, revealing aspects of the plasma behavior during such events as the internal reconnection. A simple and effective profile-reconstruction algorithm using the stepwise profile approximation permits the monitoring of the plasma density profile immediately after each shot. Cross checks between the START hydrogen cyanide (HCN) interferometer and the line integral density determined by integrating the PRR generated data shows good agreement.
