The wide band channel characterization has received, in last years, a great deal of attention since the deployment of mobile cellular radio systems using digital tecnology. The mobile radio channel is described as a time variant linear system and its tranfer function can be estimated using appropriated sounding tecniques. Two well-known sounding tecniques are studied an implemented to determine the impulsive response of some regions of rio de Janeiro city. This city a huge diversity of urban characteristics, so it an excellent environment to carry out this Kind of investigation. An extensive campaing of experiments was carried out in three different regions in the city of Rio de Janeiro. These experimental results are presented and compared. From this comparison, a series of important wide band characterization information are obtained and the performances of each one of the used tecniques are observed. Finaly, some suggestions for the continuation of this line of work are presented.