In this article, we introduce a novel blind space time processing allowing the transmission of digital communication over a frequency-selective fading channel. We show that it is relevant to use transmit diversity in such a context. Our scheme uses 2 transmit antennae and K (K ≥ 2) received antennae. We call our method Turbo deflation because it is based on results from the field of blind sources separation of convolutive mixture (i.e. deflation approach [1]) and from principle of iterative turbo decoding [2]. Furthermore it is a blind approach which means that the receiver does not need any training sequence. Our novel method could for instance be used for underwater communications where blind equalization scheme have already been introduced with really convincing performances [3].