A Wireless Direction Finder 



By J. Andrew White 



WITH its primary object to enable a 

 ship's navigating officer to take 

 bearings in fog or under unfavorable 

 weather conditions, the development of 

 the radio-goniometer, or wireless direc- 

 tion finder, has disclosed many applica- 

 tions on land and sea, in peaceful quar- 

 ters and in the center of hostilities. It 

 is reported by an engineer recently re- 

 turned to this country that the British are 

 employing this new instrument for scout- 

 ing purposes, and on one occasion se- 

 cured the position of the Admiral's flag- 

 ship of the "hidden" German fleet. Its 

 aid as protector of ships and human life 

 was still more recently demonstrated by 

 the captain of a Norwegian merchant 

 vessel in the presence of officers of the 

 Royal Norwegian Navy, an army en- 

 gineer and two telegraph and radio in- 

 spectors. 



The experiments were conducted with 

 naval vessels off the Norway coast and 

 the report of the trials as rendered by 

 Captain L. C. Hjortdahl stated that the 

 signals were good even at a distance of 

 130 miles and were heard at 240 miles. 

 At a distance of 34 miles bearings taken 

 through the Flekkero wireless station 

 corresponded exactly with the ship's 

 position and a series of bearings secured 

 with the direction finder in a voyage be- 

 tween Christiania and Bergen disclosed 

 the positions of various warships scat- 

 tered along the coast. In the port of 

 Bergen tests were made with a warship 

 lying but one-third of a mile away, prov- 

 ing that it is possible with this new in- 

 strument of science to take the position 

 of other steamers in foggy and thick 

 weather even at short distances, and thus 

 avoid collisions. 



In the absence of definite reports from 

 the British military and naval forces, 

 which will of course not be available until 

 the end of the war, the details of the in- 

 vestigations pursued by Captain Hjort- 

 dahl stand as the only complete record 

 of what may be expected of the newest 



device to insure safety at sea. Mean- 

 while government inspectors are experi- 

 menting on land to determine the useful- 

 ness of the apparatus in detecting the 

 whereabouts of interfering amateur 

 wireless stations, and commercial opera- 

 tors are finding a new effectiveness in 

 "screening out" messages not wanted 

 when working in crowded waters. 



Since the earliest days of wireless 

 telegraphy the problem of determining 

 with an instrument the direction from 

 which radio signals arrived has engaged 

 the attention of inventors. Ten years 

 ago Marconi began the preliminary in- 

 vestigations that bore fruit two years 

 later in an apparatus evolved and patent- 

 ed by two of his countrymen, Dr. Ettore 

 Bellini and Captain Tosi of the Royal 

 Italian Navy ; the device as developed 

 was not adapted to ship working, how- 

 ever, and the intervening years were de- 

 voted to perfecting an equipment entire- 

 ly satisfactory for use by navigators. The 

 apparatus in use today permits bearings 

 to be taken within two or three degrees 

 of accuracy and is technically known as 

 the Marconi-Bellini-Tosi radio-gonio- 

 meter. It is not claimed for the inven- 

 tion that the bearings taken by this means 

 exceed, or even equal, in accuracy those 

 secured by the optical instruments of 

 navigators, but the utility of the instru- 

 ment is found in obtaining reliable bear- 

 ings when direct readings cannot be 

 taken because of unfavorable weather 

 conditions. It is not necessary to swing 

 the ship to secure a reckoning, and the 

 range of the instrument exceeds the dis- 

 tances required in practical working, be- 

 ing largely governed by the power of the 

 wireless station from which the signals 

 are being received. 



The complete equipment consists of 

 the goniometer, a tuned wireless tele- 

 graph receiver, a tuned buzzer tester, an 

 angle divider and a special arrangement 

 of aerial wires. Apart from the ordinary 

 aerial or antenna swung between the 



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