A receiving system dynamically searches a communications band for transmissions of messages having the same nominal communications parameters, including the use of the same spreading code, but having potentially different specific frequencies and code-phases. The receiver samples the communications band at each code-phase of the spreading code over a span of down-converted transmission frequencies. When a message element is detected at a particular code-phase and frequency, it is forwarded to a demodulator that demodulates the message and sends it to its intended destination. This technique allows each transmitter to be independent of the receiver. In a preferred embodiment of this invention, a Fast M-Sequence Transform (a Walsh-Hadamard Transform) is used to determine the power level at multiple code-phases at a given frequency in parallel, thereby substantially reducing the time required to search for transmissions at each discrete code-phase.