The use of television signals for time and frequency dissemination

Measurements indicate that a television microwave path is stable to a few microseconds over a period of months. The paths measured are those used by the three major U. S. television networks between Washington, D. C., and Denver, Colo. Path stabilities of ±5 ns (for half-hour periods) were measured by observing the phase of the television color subcarrier. A time dissemination system using the television signal format is described. Using locally broadcast VHF television signals, time information was recoverable with a resolution of several nanoseconds. This corresponds to a frequency stability of a few parts in 10¹²for one hour averaging.