@nazokiyoubinbou @popio @paco @jerry Actually, the propagation velocity in a coaxial cable is a function of the dielectric constant and for typical materials like Teflon and other fluorinated plastics the propagation velocity is around 0.66 * C.So over sufficiently long ranges, ignoring resistive losses etc, you will actually see significantly less latency over the air than in a coaxial cable.The propagation velocity of optical/RF signals in vacuum is C by definition, in air it's very slightly slower but not by enough to matter. In glass it's reduced by the refractive index of the fiber, I don't have typical numbers off the top of my head there.