WIRELESS TELEGRAPHY.

Nelson Evening Mail, Volume XLVII, Issue XLVII, 11 April 1912, Page 2

WIRELESS TELEGRAPHY.

DR MARCONI ON DEVELOPMENTS. LONDON, Feb. 21. At the annual dinner of the Junior Institution of Engineers, at the Cecil Hotel. Dr Marconi h'a<l something interesting to say concerning the development of wireless telegraphy, of wave group tuning, the possibility ol avoiding mutual interference with messages. He said that since the occasion when he read tirSt .paper before-the Institution 13 Vears ago, wireless telegraphy had travelled a long way —not merely in the distance it covered, but in practicability. reliability, and efficiency. High-speed apparatus had now been introduced which would enable radio-tele-graphy to compete successfully with I long-distance cables in the nntter of speed. He thought the improvements | introduced in cable working were applicable to wireless telegraphy. The speed of wireless telegraphy was more or less a mechanical problem. Difficulties in wire-, less transmission caused by atmospheric electricity had been gradually but surelyovercome. There had been improvements in/the receiver and the effective utilisation of a larger amount of energy in the transmitters. The impulse at the receiving station was so much stronger than it used to be at a given distance, that the natural effects did not have the same "pull" that they need to have. Interference in ship work, due to atmosnlieric conditions, was very small. The improvements had advanced so much that- frequent communication was obtained in the tropics between stations overland for 'n distance of 1000 miles. . MUTUAL INTERFERENCE.

With regard to mutual interference thev had onlv one ether, and were dent upon it for light, heat, cable, wireless, and telephonic messages. Interference between ships had, however, been minimised.-and it had been proved practicable to have a lareer number of highpower stations in England or Ireland without mutual interference. The extended use of wireless communication was dependent upon the ease with which a number of stations could be worked efficiently without interference. Some interference did take place, but Dr Marconi thought that was due to the fact that the International Convention on rad:otelegranhv had limited the wave lengths. It would be an advantage, in his opinion, I if a third and longer wave was authorised. Three years" ago there were comparatively few ?hips equipped with ra-dio-telegraphy. The number now was very large, and in finance and commerce the receipts from messages showed much greater increase. compared with tnree years ago. That result would not have been obtained if "interference" had increased with the additional equipment of vessels. They must bear in inind that the wave lengths at present Available ranged , according to his experience, from 6in to 30,000 ft. Communication for several miles, couid be obtained with a wave length of 6in, while for long Transatlantic distances longer waves were used. Moreover, they had wave-group tuning and directive systems (available, which tended to overcome mutual interference. The waves, as a result of oscillation, .spread a bit, but they did not go all round, and become a nuisance to people who did not want tnem. (Laughter.) Those and other developments with which lie was in touch made him feei convinced that the comparatively new method <if communication was destined to fill a place of the greatest importance in facilitating communication throughout the world.

COMPETITION OF THE 'PHONE. Professor J. Perry, submitting "Electrical Intercommunication." stated that wave telegraphv although only in infancy. had shown an enormous amount of progress and promi.se. In cable work there had been also an enormous development'/ One cable from the Azores could send/220 letters a minute. There were 11 cables across the Atlantic, which meant that in ten minutes four newspaper columns could be sent across the Atlantic. Sir Henniker Heaton had talked about sendine messages at >kl a word, but the general public did hot know the difficulty of quickening up the speed of cables. There were 6,000.000 telephones in the United States. He was assured that they would be able to telephone from New York to San Francisco, and from London to -any part of the British Ifles in a very short time. In a few vears people in Teheran, Persia, would be able to hear a Covent Garden opef'a.