Orthogonal broadband signals (adaptive instant record, AIR Signals) are constructed that are particularly suitable to shallow water multipath propagation. They have similarities with the multi-carrier code division multiple access (CDMA) methods which have arisen from mobile telephony, and allow communication between several sources and several receivers. The period of the orthogonal signals is related to the channel time spreading in order to provide an exact and simultaneous measure of the transfer function between all sources and receivers on the whole transducer frequency band. This method which optimizes the signal-to-noise ratio is relevant to fluctuating environments and particularly to time reversal applications. The first experimental demonstration at the ultrasonic scale has shown the efficiency of these signals in a stationary environment as well as their robustness to absorption and to bottom reverberation. This presentation describes the experimental use of these signals with a time reversal mirror in the Mediterranean Sea during an April 2003 experiment.