Metroliner telephone article 4103

At radio frequencies, which is what we are talking about here, the signal travels on the surface of the wire and doesn't penetrate the metal to any depth. Thickness of metal is only important insofar as it increases the surface area. The key factor is the skin resistance of the wire which is a function of the material, the surface area and the degree of corrosion etc. as well as the dielectric constant and losses of any insulation. Also power lines are poorly designed for use as transmission lines. Unlike, say, phone lines where the wires are constant diameter and spacing and make quite a good transmission line, power cables are wide (and usually variably) spaced and the spacing to earth varies. This makes for a widely varying impedance and significant losses, not to mention radiation. Buried power lines as used for local distribution in the uk are free from most of the problems, but the supply has to come above ground somewhere! I imagine those parts of the US that still have overhead power distribution would have severe interference problems!

-- Cheers, Stan Barr stanb .at. dial .dot. pipex .dot. com (Remove any digits from the addresses when mailing me.)

The future was never like this!