IMPERIAL WIRELESS

New Zealand Times, Volume LIII, Issue 12622, 6 December 1926, Page 4

IMPERIAL WIRELESS

WORLD LEADERSHIP OFFICIAL TEST PASSED BY BEAM STATIONS CIRCLING THE EMPIRE The Marconi Company has received from the engineer-in-chief of the Post Office the official certificate that the wireless stations constructed at Bodmin and Bridgwater for communication with Canada on the Marconi short-wave beam principle, have passed their official seven days’ test, and the General Post Office announces that a high-speed wireless telegraph service between Great Britain and Canada through these stations has been opened. With the first Dominion beam service thus established Great Britain's world leadership in wireless communication is maintained. As the homo of Senatore Marconi s first \ong-distance wireless experiments Great Britain was the pioneer country in commercial wireless telegraphy. And now, with the modern high-power valve transmitting station at Rugby for all-round communication, and the Marconi beam stations for direct communication between the Mother Country and each of the Dominions, it possesses the most complete, up-to-date and efficient wireless service of any country in the world.

A FAR-REACHING REVERSAL OF POLICY It was in 1923, after several years of discussion, that the Government definitely decided to proceed With the erection of wireless stations to communicate with each of the Dominions. The Dominions had been pressing for such a service for some years, and when tho British Government’s decision was taken they immediately put arrangements in hand for the erection of corresponding stations to form a complete Empire wireless service. Senatore Marconi became convinced, as tho result of his experiments, that a new system of wireless telegraphy could be developed that would enable these Imperial services to be carried out much more efficiently and at much lower cost than was contemplated by the high-power long wave wireless stations. His plan was to use short wireless waves—of 100 metres or less which, contrary to the generally accepted theory at that time, he had proved to bo quite reliable for communicating over great distances: and to increase the strength of signals and the speed and efficiency of working by employing reflectors to concentrate into a narrow beam the wireless energy at the transmitting station and to reflect a greater amount of energy on -to the receiving aerial at the receiving station. As Senatore Marconi has said, a considerable amount of courage was necessary to propose such a revolutionary change. He had no uncertainty, however, neither had the company of which he is the chairman; and the proposal was put before the Government. So convincing were the arguments in favour of the new system that the whole technical policy of Imperial wireless communication was revised and the Government entered into a contract with Marconi’s Wireless Telegraph Company* Ltd., to build short wave beam wireless stations in England..t®,/ oommunicate with Canada. South, Africa, Australia and India. The Govern-, ments and wifeless companies m each of these Dominions were equally impressed with the value of the beam system and contracted with the Mar • coni Company to build corresponding stations to communicate with those being erected in England. The building of the stations was started in April, 1925. They have been longer under construction than was at first anticipated, but this has been due to the fact that research work has been carried on simultaneously with constructional work and many valuable improvements on the original designs have been made as the work progressed. Power valve:; have had to he specially designed to deal with tho extra high frequencies of short wave working, and tlie marconi oil-cooled valves at the transmitting stations are the most efficient of their kind in tho world.

EXTRAORDINARY SPEED OF SIGNALLING

’The official Post Office tests laid down that tho stations for the Canadian service should be capable or communication at a speed of 500 letters per minute each way (exclusive of any repetitions necessary to ensure accuracy) during a daily average of 18 hours, and that a demonstration fulfilling tliis condition should be given by actual working for seven aonseoutivo days. This teat took place between October 7th and October 14th, and the guarantees —which were regarded by everyone as being extremely stringent—have been fulfilled. During these and the preliminary tests carried out by the Marconi Company speeds of 1250 letters per minute in each direction equal to 2500 letters per minute over tho complete circuit have been worked for many hours oil end. Counting every hour of the seven days’ test the average speed of signalling has been about. GOO letters per minute in each direction or 1200 letters per minute for tho complete circuit. ADVANTAGE TO COMMERCE

The institution of direct Marconi wireless telegraph services between London and Paris and other continental centres has shown that new telegraph traffic is created by tiio provision of new and rapid means of communication. It can, therefore, be con. lidently anticipated that tlio establishment of the beam services, which can be worked at a speed which will enable large volumes of traffic to he dealt with in the shortest possible time, will create new business that has not previously been possible, and so bestow a. groat benefit on the commerce of Great Britain and Canada. The sites occupied by the beam stations at Bodmin and Bridgwater for communication with Canada are also utilised for the stations to ho used for communication with South Africa. These South African stations are practically complete. Similar stations are being built at Tetney, near Grimsby, and at Winthorpe, near Skegness, lor communication with Australia and India —the Grimsby stations being transmitting stations, and the Skegness stations receiving stations. Corresponding stations are being built in the Dominions near Capetown, Melbourne, and Bombay. All those stations are in an advanced state of ; construction, and are expectH to hs , opened within the next lew mouths. This will complete the present Imperial scheme: but outside this r.'-heum 1 the Marconi Company is already en- 1 gaged on n considerable development of commercial telegraph services

on the beam principle. The company holds a license from the Post Office to conduct wireless telegraph services with certain continental countries, and with all other foreign countries outside Europe. ADVANTAGES OF BEAM SYSTEM It is claimed that a beam wireless station has tlio following distinct advantages over any other form of telegraph communications for point to point communication over similar distances —the capital expenditure involved is considerably less; it is more economical to run and maintain; and it is by far the most speedy method of communication yet devised. The speed of working of the beam system is at present limited only by the mechanical limitations of the transmitting and recording instruments, and when suitablo means of recording over landlines at higher speeds than at present obtainable have been developed it will be possible to increase correspondingly the overall speed of signalling. DESCRIPTION OF STATIONS The Bodmin station, which is built upon a strip of land bordering the main Boumin-Truro road. 41 imii-s south-west of the Cornish county town, comprises two transmitting systems, one for communication with Canada and the other for communication with South Africa. The receiving stations are situated near North Potherton, 2-J miles south of Bridgwater, off the main Brldgwater-Tnunton road. The masts and aerial system —the design of which is peculiar to the short-wave beam system, and is en-

tirely different from the design previously used in commercial wireless stations—are similar at both stations. Thcro are five lattice steel masts lor each service erected iji a straight lino and aligned so that tbe great circle bearing ""on the distant station is at right angles to the line of masts. The beam is, therefore, projected accurately in tho direction of the stations with which communication is being maintained. The masts are 277 ft high, with cross arms at the top measuring 90ft from end to end, and .siring an additional 10ft to tlio height of the mast. The aerial and reflector systems consist of a number of vertical wires, forming as it were a wire curtain, suspended from steel cables attached to the cross arms and running along each side of the row of masts. The aerial system is on one side of the masts, facing the distant station, and tho reflector system is on the opposite side. In tho same way, the messages put on to the transmitter in the telegraph office in Montreal are instantly recorded at tho General Post Office in London. after having traversed the Atlantic and passed through the beam receiving station at Bridgwater .Now that the Canadian station has been completed satisfactorily, the pre* : limjnnry tests will at once bo proceeded with in the case of communication between England and South Africa. ; On the completion of these tests, those j with Australia aml India will I'oOnw. the construction of beam stations for all these services being nearly completed*