A finite amount of time
is required for a signal to travel from one place to another. In a vacuum, electromagnetic energy travels at
m/s. The following equation holds for signal propagation time in a vacuum, where the
dielectric constant is 1.
If a radar type system is being evaluated where a round trip out and back needs to be accounted for, then double
the distance figure. A “radar mile”, which is a nautical mile out and a nautical mile back, is 12.36 μs.
Here is a 1-way propagation time calculator
Here is a
2-way propagation (round-trip) time calculator