LAYING THE CABLE.

New Zealand Herald, Volume LXIII, Issue 19303, 16 April 1926, Page 13

LAYING THE CABLE.

INTER-ISLAND TELEPHONE.

THE WORK IN COOK STRAIT.

A NOTABLE# ACHIEVEMENT. BY WAREPA. On Good Friday eve the newly-laid telephone cable across Cook Strait was made available for conversations between Wellington and Blenheim and Nelson. While the quality of the speecli was not then first-class the new cable is not to blame for this, and day by day there lias been perceptible improvement.

Until such time as permanent underground circuits have been laid from Wellington to Lyall Bay and from Blind River to Seddon the audibility of speech will leave something to be desired. During the trial' speeches, however, over the actual cable itself, from Lyall Bay to Blind River, which preceded the opening of the cable for limited traffic purposes, the audibility was excellent and was little, if any, inferior to that obtaining between subscribers within any city exchange area.

Until the permanent land lines, therefore, have been laid at the northern and southern shore ends, communication will be maintained by improvised circuits which can hardly be expected to ensure perfectly clear transmission. Doubtless the Telegraph Department would have preferred to have awaited the completion of the permanent land lines in the belief that indifferent audibility over the improvised circuits would not bo a good advertisement, for the much-heralded telephone cable, but it may be imagined that representations were not lacking that the cable should be opened for the Easter holidays and for the busy Nelson apple season now in progress. Three Phases of the Cable. It should be borne in mind that there wfll be three distinct phases in connection with the operation of the cable. The first with respect to the limited facilities is now in progress, and the second will represent the improved speech with the same limited facilities when the permanent land lines arc laid.

The third and most important and farreaehing, from a Dominion viewpoint, will be tho installation of repeaters on the valve amplifying principle, which will repeat speech on with undiminished volume and clarity. This will enable telephone conversations to be obtained throughout the day and night between Auckland and Invercargill and intermediate places. It will be some months before the final stage of the inter-Island working of the cable is reached.

There are four copper conductors in the new cable, their size representing No. 13 standard gauge. Each of the conductors is reinforced by three brass tapes wound spirally round it. Outside tho brass tapes is a winding of fine iron wire which provides what is known as "continuous loading." This is designed to balance the capacity of the cable, which would otherwise have the effect of distorting speech. In brief, the loading will nullify the distortion induced by tho capacity. Each of the four copper conductors is insulated by balata, followed by a protective covering of tinned brass tape. To tnis is added a thick layer of jute, which in turn is covered by the spiral armouring of heavy iron wire. A final covering of jute completes the cable. A Fine Achievement. - The work of laying the new cable was completed witlTout the slightest hitch and no finer achievement of the kind lias been carried out in New Zealand waters by officers of the Post and Telegraph and Marine Departments. Tho equipment of the Tutanekai for the work was undertaken some time before tho arrival of the cable from England by the Tongariro and no time was lost in transferring the cable from the one vessel to the other. On March 22 the Tutanekai left Wellington for Blind River, the South Island terminal point, taking soundings en route. Excellent progress was made, which enabled the South Island shore end to be laid and buoyed the following morning, after which the Tutanekai stood on her course to Lyall Bay, Wellington, which was reached in the evening. Unfortunately the weather was unpropitious on March 24 and operations were suspended. Early next morning, however, the workwas resumed and by 8.45 the Lyall Bay shore end had been laid and the Tutanekai again left for Blind River, paying out the deep-sea portion of the cable m her wake. , , The ship reached the Blind River buoy at 5 p.m., well ahead of schedule time, and there remained only the final splices to be made. A portion of the work was deferred until the morning of March and shortly before nine o clock the filial stages were readied and tho complete cable was lowered gently over tho bo«s of the Tutanekai to its final resting place and the vessel returned to Wellington. The Work of Testing. Throughout tho work of laying the cable. a continuous watch was maintained by testing officers at Lyall Bay. Ihe.foui conductors were connected to testing instruments in a hut on the beach. When the Tutanekai commenced to pay out tho ocean cable on her second trip to Blind River the testing officers were in communication with tho vessel all the time and progress was thus reported to shore. The testing was carried out by means of a highly sensitive mirror galvanometer bv which the insulation resistance of the cable was measured and by which any faults developing would have been localised. Fortunately tho new cable responded in a most satisfactory manner to all tho tosts made. Although the main anxiety of the responsible officers ceased with the successful laying of the ocean cable a considerable amount of work is involved in laying the trench cables between Wellington and Lyall Bay and Blind River and Seddon. These lengths of trench cable have been specially imported and will be encased in vitrified ducts in accordance with tho usual practice with respect to underground telephone cables. Tho work at. the Blind River end will probably bo expedited if the department is to use a plough or excavator in preparing the trench in which the land cable will be laid. It may be safely assumed that the completion of the land circuits will be regarded as a work of paramount importance and will be followed at an early date by tho equally important work of installing the " repeating " apparatus.. Benefits of the Cable. When tho cable is functioning at maximum, day and night, the long-distance telephone system in New Zealand will W completely revolutionised. The Auckland merchant will be able to ascertain almost immediately tho state of the Southland oats market, while the Invercargill and Dunedin merchants will be similarly placed as to inquiries regarding Island oranges and bananas at Auckland. And although the Government frowjw any suggestion of culpability in the matter of providing betting facilities it mav be possible, before the next New Zealand Cup is run at Riccarton .tor"the Aucklander who has heard something reallv good at tho eleventh hour up a Christchurch friend and have hi money placed right on the machine.