I'm not a newbie, but this is a question I've wondered about for a while and never seen answered. We know that AV cables should have the proper impedance. TV coax, such as RG-59 and RG-6, is said to have 75Ω "nominal impedance." Component video cables are the same. Here's my question. How can, say, a 1m cable have 75Ω impedance and a 2m cable also have 75Ω impedance? Resistors in series impose the sum of their resistance, so wouldn't a 2m cable have 150Ω impedance? The same as two 1m 75Ω cables connected in series? What am I missing? Is this really impedance per unit length?