Variables Er Relative dielectric constant P Power factor of dielectric D O.D. over dielectric (inch) S Stranding factor of conductor d O.D. of conductor (inch) F Frequency (in MHz) W O.D. of shielding strands Stranding Factor Solid 1.000 105 Strands .988 65 Strands .985 41 Strands .980 19 Strands .970 7 Strands .939 1. Capacitance (C): Picofarads per foot Definition: The ability to store an electrical charge. 2. Characteristic Impedence (Z0): Ohms Definition: The ratio of voltage to current in a cable of infinite length.     or 3. Inductance (L): Microhenries per foot Definition: Resistance to change in current.   4. Velocity Of Propagation (VP): Percentage (%) Definition: The transmission speed of an electrical signal traveling a length of cable as compared with the speed of light in free space. 5. Time Delay (TD): Nanoseconds per foot Definition: The amount of time required for an electrical signal travel a specified frequency. Where a1 and a2 are constants of the cable.