THE WIRELESS COMPASS

New Zealand Herald, Volume LI, Issue 15563, 21 March 1914, Page 8

THE WIRELESS COMPASS

THREE KINGS PROPOSAL. WORKING OF APPARATUS. FINDING SHIP'S POSITION. The suggestion of the Minister for Marine that the "wireless compass" should be adopted for the purpose of guarding shipping against the danger of the Three Kings . has aroused a remarkable degree of interest, and some hostile criticism. Mariners in particular have expressed opinions unfavourable to the suggestion, and have urged, in spite of the stated objections of the Minister, the installation of a light- ' house. A feature of many of the published objections is that the critics say they know nothing of the wireless compass, and they imply a distrust in it as a means of warning. Inquiry was made yesterday by a Herald representative into the nature of the invention. The wireless compass is a comparatively recent though not by any means a really new, adaptation of wire- ! less telegraphy. It is not a warning device, any more than is the sextant, but j is an appliance for enabling a vessel with- ! in short range of some shore station to j establish her own position on a chart. A light, of course, does the same thing, but, primarily, being itself visible, it indicates first its own position relative to the ship. According to the expert information obtained, any wireless station, either ashore or afloat, can provide a properly-equipped vessel with her position. Wireless messages radiate all round the sending station, and cannot be confined to any particular direction, and a land station, such as is proposed for the Three Kings, specially instituted for compass duty, differs little, if at all, from any other as far as its sending apparatus is concerned. But by means of the " wireless compass," the receiver of a message can tell exactly from what direction it arrives. The apparatus consists of a special receiving outfit, _of which a principal part is a duplex aerial, of which half the wires cross the rest at right angles. The two halves are connected with apparatus and rolling an indicating needle". If a message arrives from a direction towards which one set of wires exactly points, those wires pick irp little or no impulse, but the others, being at right angles, obtain a maximum of the wireless waves. If both the sets lie obliquely to the arriving waves, they pick up the impulses, varying in proportion to the angle at which* the waves strike them. The electrical apparatus connected with the aerials and controlling the indicating needle is such that the needle swings, according to the proportionate energy, picked no by the two aerials, directly towards the sending station. Any vessel carrying the "compass." and knowing her own course and rate of nrojrress, can take : two or more bearings of the sending station, and by simple navigating practice es- ! tablish her own exact position at the times the messages were received. Similarly, if it is desired, a land station possessing a "compass" can tell the direction in , which an inquiring ship lies, and can send , replies accordingly. There is nothing special about the messaees sent out from a land station to "wireless compass" vessels. Mariners in the South have questioned whether the presence of different vessels in , the vicinity of the station would not have a confusing effect. But it is explained that such confusion is unlikely, and if it should occur the land station has the right 1 to order all but one vessel to " keeD out" ' till the other is satisfied. The wireless compass is not yet in ' (reneral use, but it is stated that it has had sufficient trial to have i>°en proved thoroughly efficient and reliable. i The cost of a wireless equipment suiti able for use with a wireless compass and , for ordinary shins' service is said to be , about £150: and the great majority of vessels passing the Three Kintrs are stated ' to be equipped already with the ordinary * apparatus. - A meetine of shipmasters in active service and out of service will he held at the Harbour Board's office at 11 a.m. on Monday to discuss the nronofed wireless ! station on the Three Kings.' It is antici ■ pnted that the meeting will be largely " attended by captains of vessels who have traded regularly to this port.