What is standard TV coax?
Standard TV coax (RG-6) is 75 Ohms. Most radio/network coax (RG-58) is 50 Ohms.
Calculator
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Analysis
Interpretation of the current calculator output
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How to Use
Step-by-step instructions
- 1Select the cable type (Coaxial or Twisted Pair).
- 2Enter the inner conductor diameter (d).
- 3Enter the outer diameter (D) or spacing.
- 4Enter the dielectric constant (e.g., 2.2 for PE, 1.0 for Air).
- 5The calculator will show the impedance in Ohms.
Coaxial Impedance
Calculates characteristic impedance based on the ratio of outer (D) to inner (d) conductor diameters and the dielectric constant (ε).
Z₀ = (138 / √ε) × log₁₀(D/d)Variables:
DOuter Diameter / SpacingdInner / Conductor DiameterεDielectric ConstantExample
RG-58 Coax
Inputs:
Type:Coax
d:0.81 mm
D:2.95 mm
k:2.26
Steps:
- 1.Z0 = (138 / sqrt(2.26)) * log10(2.95 / 0.81)
- 2.Z0 = 91.8 * 0.56 = 51.4 Ohms
Result:
~50 Ohms