NAVIGATION AIDS

Dominion, Volume 16, Issue 148, 10 March 1923, Page 3

NAVIGATION AIDS

WIRELESS DIRECTION

FINDING SUCCESSFUL GOVERNMENT TESTS Successful tests of a wireless direction tinder as a i aid to navigation have been conducted by the Government. As a result, the Government favour the installation of directional receiving apparatus aboard ship, apart from the usual wireless equipment, and (die establishment of a radio beacon on shore. Lie results of the tests were communicated to the Pri ss by the Minister of Marine (Hon. G. -J. Anderson) yesterday. “At present,” he said, “there are two distinct principles in the application of wireless direction finding to marine navigation. Those are: (1) By locating the direction finding stations in fixed positions on shore, from which the ship receives its pt sition through tho medium of ordinary wireless set. (2) By installing lirectional receiving apparatus aboard the ship—quite apart from the usual wireless i equipment—and establishing a radio beacon on shore. “The Government steamer Tutanekai was utilised for tests of No. 2 principle, which were carried out during tho last northern tour of the lighthouses and other Marine Department’s interests. A radio beacon station was established on a selctcted site on the Great King, tho largest of the Three .Kings Islands, and an up-to-date direction finding instrument was installed in tho navigation room on the vessel. Experienced wireless and navi gation experts accompanied the vessel tind conducted the tests. The shore station was si l uated about the centre of the caste, ti end of tho island, at an altitude yf 380 feet above sea level.

“The tests were carrLd out during the greater part of tv,o days and nights, during which time no serious hitch occurred to mar the success of the operations. The signals transmitted by the station were received bv Awanui Radio at a distance of 77.? nautical miles, and by merchant ships at quite readable strength at a distance of 100 mjles daylight. On the last morning of me tests, owing to fog. neither tho islands nor any other land was visible. Direction finding testa were taken continously, and when the islands became visible, it was found that their true direction coincided with the bearings taken during the fog by tho direction finci.ng instrument. “As a result of the lests the Department is satisfied tht t the principle advocated under head ng No. 2 can be applied in a practica. manner. As in tho case of a vessel’s standard compass, the direction finding instrument requires to be calibrated on each vessel and have its errors tabulated. The errors may then be applied m the same manner to 11 at. in which compass errors are applied. Regarding its tabulated errors it was noted that theso are fairly constant, also that tho errors arc at a minimum when th© observations are taken cither right ihe-ad or right astern. ’The same. may be said of bearings taken on either beam. The errors change from additive to subt.racti'vc in succeeding quadrants when using the 3GO degree system, and they follow a simple law that all observed ’Bearings” suffer deflection towards the fore and aft line of the vessel.

“Thff Department is satisfied the riytio beacon station, with its counterpart the ship’s direction finder, can be Considered a practical a.id to navigation of special significance during thick or foggy weather.”