====== Characteristic Cable Impedance ======

===== Method 1: Measure C and L of a known cable length =====

For a transmission line:

  Z0 = SQRT( L' / C' )
  
  where:
  L' = inductance per meter (H/m)
  C' = capacitance per meter (F/m)
  
==== Step 1: Measure capacitance ====
Take a known cable length l. Leave the far end open-circuit. Measure the capacitance between center conductor and shield:

C′= C_measured​​ / l

==== Step 2: Measure inductance ====
Short the far end. Measure the inductance seen from the near end. For a shorted transmission line at sufficiently low frequency:

L' = L_measured / l