Propagation of carrier signals in homogeneous, nonhomogeneous and mixed multiconductor systems

In the last few years the theory of natural modes has become an accepted form of analysis for multiconductor systems. This theory is used in the paper for two purposes; first, to determine optimum methods of carrier coupling in vertical and horizontal conductor configurations, including the effect of coupling equipment and line traps. Numerical results are given for a number of limiting conditions relating to busbar impedances. The general conclusion is reached that, in horizontal systems, coupling should be near the centre of the conductor group, in vertical systems it should concentrate toward the top of the conductor group. Secondly, the theory is extended to a nonhomogeneous system made up of a teed-feeder arrangement with a short section of cable in one leg of the tee. Numerical results are given to show the large insertion loss which occurs at frequencies which make the cable length an odd multiple of one quarter of a wavelength in the region.