R&D Report 1962-52 : The power loss from open-wire high-frequency transmission lines due to support structures. J.B Izatt, R.G. Manton The balanced open-wire transmission lines used at high-frequency transmitting stations are subject to losses due to the currents induced in the supporting structures. This report considers the magnitude of these losses in the cases of steel and reinforced concrete support structures. A method for calculating the loss is presented and it is shown that significant power is lost only when the structure is electrically resonant.