A communications device includes a signal input for receiving signals such as a binary phase shift keyed (BPSK) communications signal having a repeated preamble bit or symbol pattern. A modem processes the communications signal and includes a demodulator and processor that generates an initial frequency offset estimate and phase error estimate by processing a Fast Fourier Transform (FFT) that detects the repeated preamble pattern for a block of samples within the communications signal, correlates within a start of message correlator to search for a start of message sequence and correlates different phases of the repeated preamble pattern within training correlators for reducing false detections of the start of message. Radio circuitry is operative with the modem for processing communications data obtained from the communications signal.