Wayne wrote:
"But we're talking about a signal. If the signal"

Not according to Einstein and relativity.

A signal is energy.
Energy has mass.

Hold a flashlight and aim it out into space. Sweep it from left to right as fast as you can. There is no question, one year in the future, that the sweep of that beam will traverse one light-year in less than a second. But no message will traverse that distance faster than the speed of light.

The speed of light is the law. It must be obeyed.

DA Morgan