Imagine two rockets approach each other at a speed of v. They broadcast regular timing signals at different radio frequencies so the two signals can be distinguished. Each rocket makes a prolonged recording of the signals from both itself and the other rocket. The rockets then decelerate equally and they stop in the same inertial frame so the two recordings can be compared.

The arrival frequency of the approaching signals can be reduced by v/c to compensate for the reducing distance. Hence the adjusted rates of the signals would be identical if there were no time dilation. For each rocket, the signals could then be aligned at the start of their recordings and no time lag would develop.

SR predicts that A will find B’s signals are slower and that B will find A’s are slower. In other words the signals would be found to progressively lag each other. If the two sets of time lags were plotted as lines on a graph, A’s would be to the left of B's and B's would be to the left of A's.

Please will someone tell me how this is possible.