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Oliver Heaviside and the theory of transmission lines (2021)
Pieter-Tjerk de Boer, PA3FWM web@pa3fwm.nl (This is an adapted version of an article I wrote for the Dutch amateur radio magazine Electron, November 2021.) An antenna cable is not just a piece of wire. Technically, it's called a "transmission line", with special properties such as its characteristic impedance.
Maxwell's ideas about electromagnetism were, at that time, rather speculative and not widely accepted, but Heaviside got enthousiastic, studied them, and succesfully applied this theory to telegraph lines. The figure shows, for a coaxial cable with air as isolation, the theorectical dependence of the capacitance and inductance (both per meter) on the ratio of the diameters of the center conductor and the shield. increase G, so use a not-so-good isolation material: this is what happens when water seeps into a sea-cable (recall that Heaviside as a telegraph operator had already noticed that then the distortion is reduced), but the obvious disadvantage is that the signals become weaker.
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