New Australia-Tasmania Submarine Cable

Abstract

THE new submarine cable which was successfully laid across the Bass Strait last November marks a notable advance in the technique of submarine cable transmission. Before laying this cable, the Australian Government made a searching inquiry into the relative merits of radio and cable systems of communication, and came to the conclusion that for the objects in view the cable system was the more desirable as it is more trustworthy and easier to make the messages secret. In the Engineering Supplement to the Siemens Magazine of January, a technical description is given of this new cable. It links the telephone and telegraph service of the mainland of Australia with Tasmania. Its length of 161 nautical miles is divided into two sections. The northern section, 79 miles in length, joins King Island to Apollo Bay, Victoria, and then by overhead lines and underground cables joins the trunk exchange at Melbourne. The southern section from King Island goes to the northern coast of Tasmania and then by land line to the Launceston exchange. Inter-connexion is thus effected with the existing network of communications in Australia and Tasmania. This cable, although it has only one insulated conductor, allows no less than five telephone and seven high-speed telegraph channels to be operated simultaneously. In addition, it provides for the transmission of a broadcast programme. Subscribers in Tasmania can now communicate directly with Great Britain by telephone. The adoption of a high-frequency carrier system was influenced by the fact that it is easy to repair. Cable ships are not always available for immediate service in Australian waters and this type of cable is the easiest to repair. There are already two carrier frequency submarine cables in operation. One connects Teneriffe with Gran Canaria, a distance of forty miles, and the other Key-West to Havana, a distance of 109 miles. Both these cables operate only three telephone circuits.