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 E9(eff) Effective dielectric constant or,   Er x factor Factor 0.90 if foam insulation Factor 0.95 if solid insulation 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. or 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 to travel a specified length of cable. 6. Attenuation (A): dB per 100 feet Definition: Signal loss in a given length of cable at a specified frequency. Where: R = Resistance (AC), G = Conductance 7. CROSSTALK: dB Definition: Signal interferance between nearby conductors caused by pickup of stray energy. Where a1 and a2 are constants of the cable.