Future Application needs of carrier pilot relaying

IT IS EXPECTED that the number of carrier pilot relay installations will follow approximately the same geometric growth rate as that exhibited by the electrical industry as a whole, that is, doubling every 10 or 11 years. If space in the frequency spectrum is to be available for these additional channels, as well as for other carrier applications, steps must be taken to avoid serious frequency congestion problems, which even now are being experienced in certain areas.