Velocity of Propagation (VoP) or velocity factor is a parameter that characterizes the speed at which an electrical signal (e. g. radio) passes through a medium. Radio is the transmission of signals by Modulation of electromagnetic waves with frequencies below those of visible Light. A transmission medium' (plural transmission media) is a material substance ( Solid, Liquid or Gas) which can propagate Expressed as a percentage, it is the ratio of a signal's transmission speed compared to the speed of light in vacuum. Thus, transmission in a vacuum would have a VoP of 1 (100%). This vacuum means "absence of matter" or "an empty area or space" for the cleaning appliance see Vacuum cleaner. VoP equals the reciprocal of the square root of the dielectric constant of the material through which that signal passes. In Mathematics, a multiplicative inverse for a number x, denoted by 1&frasl x or x &minus1 is a number which In Mathematics, a square root of a number x is a number r such that r 2 = x, or in words a number r whose Measurement The relative static permittivity εr can be measured for static Electric fields as follows first the Capacitance of a test

This parameter is used for communication media such as data cables (e. g. , Category 5 cable cables). Category 5 cable, commonly known as Cat 5, is a Twisted pair cable type designed for high signal integrity Plenum data cable typically has a VoP ranging from 0. Plenum cable is Cable that is laid in the Plenum spaces of buildings 42 to 0. 72 (42% to 72% of the speed of light) and riser cable around 70%. A VoP of 70% would correspond to a speed of approximately 210,000,000 m/s or taking 4. 76 ns to travel one meter. A nanosecond ( ns) is one billionth of a second See also times of other orders of magnitude. In some technologies, such as Ethernet/Fast Ethernet the maximum length is dependent on the propagation delay of the medium. Ethernet is a family of frame -based Computer networking technologies for Local area networks (LANs In Computer networking Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s against the original

## Typical velocity factors

From table 19. 1 in the ARRL Radio Amateur's Handbook, some typical velocity factors:

VF%Transmission line