Post-war and on to 1975 (continued)

As the network of trunk wires and cables grew and high voltage power systems began to form intrastate and later interstate grids, issues relaying to co-ordination of the two systems began to emerge. On the one hand it was necessary to avoid both high frequency induction, with associated noise levels, and low frequency induction, with the risk of dangerous voltages, into the telecommunications system, while on the other the optimum location of powerlines involved important cost considerations. Comprehensive co-ordination arrangements were therefore developed through the active participation of the power industry and the APO at both national and State levels.[43] Avoidance of overvoltages, due to lightening discharges, also involved quite extensive development of practices, based on theoretical studies, in the interest of protecting staff, customers and equipment.[44]

Although unspectacular in terms of visible technology, the provision of ducts and cables for main systems, pit and pipe for reticulation, pillars and cabinets for economic control of distribution, and cables buried directly in the ground, involved substantial capital investment and influenced maintenance costs and system performance in major ways. Extensive on-going work was undertaken in conjunction with the cable factories on cable design ranging from materials for insulating conductors, to wire gauge, wire configuration to control performance, to sheathing materials. Development of installation practices, under H. M. Fitzpatrick, was a parallel activity involving an extensive range of such diverse matters as the direct ploughing to depths of 1.2 metres in the case of long distance coaxial cables,[45] to the machine jointing of cable pairs and the sealing of new types of sheathing materials.

23 Joining Coaxial Cable, Victoria

24 Laying Sydney-Melbourne Coaxial Cable

The rapid growth in the network which has been briefly described, the even more rapid increase in the number of trunk calls, the introduction of single operator control and finally the move to subscribers dialling their own trunk calls, progressively changed the network from a number of relatively small local networks connected together under the supervision of an operator or operators to a national one, and later to a segment of an international network, in which calls had no operator supervision. These changes required corresponding improvements in the performance of the whole network and in each of its elements, necessitating in turn the development of performance indicators and performance evaluation methods, and also improved and systematic testing and new approaches to maintenance. For these processes to thrive an attitude within the organisation which facilitated innovation was required at various levels, and progress was often made in conjunction with the intregration of new systems and new equipment into a working environment. Here only a sample can be given of a range of initiatives which were taken.

Australian Academy of Technological Sciences and Engineering