A method and apparatus for enabling a radio to track channel timing and support channel scanning A non-leading radio operating on a communications channel, determines a diffusion period during which channel timing is to be propagated from a leading radio to non-leading radios operating on the communications channel. Sequenced frame images are formed based on the captured images. Two upper and two lower control lines are distributed around the leading edge and are connected at the other end to a control system designed to keep the two left lines separated from the two right lines and varying the length of the upper lines relative to that of the lower lines.