Embodiments of the invention provide a method to detect DSSS preambles in smart utility networks. A DSSS signal is received by a receiver and a digital sequence of samples is formed. A difference value is calculated between pairs of samples in the digital sequence of samples to form a sequence of differential values. A known preamble differential value sequence is correlated with the sequence of differential values to form a sequence of correlation values. A location of the preamble is located in the digital sequence of samples corresponding to a peak in the sequence of correlation values that exceeds a threshold value.