Typical Velocity Factors
Velocity factor is an important characteristic of communication media such as Category 5 cables and radio transmission lines. Plenum data cable typically has a VF between 0.42 and 0.72 (42% to 72% of the speed of light) and riser cable around 0.70. A VF of 0.70 corresponds to a speed of approximately 210,000,000 m/s or 4.76 ns to travel one meter.
Some typical velocity factors for radio communications cables are provided in the ARRL Handbook:
| VF% | Transmission line |
|---|---|
| 95-99 | Open-wire "Ladder" Line |
| 80 | Belden 9085 twin-lead |
| 82 | RG-8X Belden 9258 coaxial cable (foamed polyethylene dielectric) |
| 66 | RG-213 CXP213 coaxial cable (solid polyethylene dielectric) |
Read more about this topic: Wave Propagation Speed
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