Radio Broadcast (Nov 1926-Apr 1927)

FEBRUARY, 1927 LINKING CONTINENTS WITH TWENTY KILOWATTS 355 that the signal strength is practically the same no matter what the strength of the incoming signal. MARCONI PRAISES "HAMS'" EFFORTS IN THE course of his address on the beam system, Senatore Marconi made some interesting remarks relative to the value of the amateurs' share in short-wave development. "The results obtained by amateurs in the field of short-wave endeavor do great credit to them," he said, "especially if we consider that most amateurs possess only limited facilities for experimental work. It should not be forgotten that amateurs were the first to carry out two-way communication with New Zealand for brief periods. Their observations have often been of value in helping us to arrive at a somewhat better understanding of the very complex phenomena involved, but I think it is sometimes dangerous to attach too much importance to all their observations, especially when they concern what I might term 'negative results.' Only the other day I, read a statement by an eminent authority that, according to amateurs' observations, the daylight range of a 100meter (2998-kc.) wave did not exceed 200 miles, and for a 50-meter (5996-kc.) wave 100 miles. I have carried out tests on a 100-meter wavelength for months on end and have never found its daylight range to be below 1000 miles. With a 47meter (6379-kc.) wave, which is close to 50 meters, we have never observed any skip distance commencing at 100 miles or at anything like so short a distance. It may well be that some of the observers were not particularly skilled, or were using insensitive receivers or that their stations happened to be situated near buildings or structures which unfavorably affected receiving. I therefore think it would be unfortunate if, in consequence of some reports, the theory of skip-distances should become unduly generalized and extended. " I have found that, for reliable observations and deductions in regard to the behavior of transmissions over varying distances, there is nothing so good as a receiving station installed on a suitable ship." LOCATION OF THE BEAM STATIONS THE beam transmitting station in Canada is situated at Drummondville, 30 miles east of Montreal, and the receiving station at Yamachiche, 25 miles north of Drummondville. These stations are linked up by land line to the central office of the Canadian Marconi Company in Montreal in the same way that the English stations are linked to the General Post Office, in London. Beam stations are also being erected in Canada for direct communication with Australia, and corresponding beam stations are being built at Melbourne. The sites occupied by the beam stations at Bodmin and Bridgwater in England, for communication with Canada, are also utilized for the stations to be used for communication with South Africa. These South African stations are practically com H'Horizontal Support Wires R=Reflector Wires Two to each Antenna Wire A-Vertical Antenna Wires CPhasing Coils 1 = Insulators Reflector Wires end at safety Hook ft f 1st Mast Antenna Wires go to Feeder System via Coupling Box 2nd Mast THE BEAM ANTENNA SYSTEM Showing the position of the antenna and reflector wires in relation to each other, of the insulators, phasing coils, supporting wires, and towers are also shown. tenna wires and thirty-two reflector wires to each span The relative location There are sixteen an plete. Similar stations are being built in England at Tetney, near Grimsby, and at Winthorpe, near Skegness, for 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 Cape Town, Melbourne, and Bombay. All these stations are in an advanced state of construction, and are expected to be opened within the next few months. This will complete the present Imperial Scheme; but outside of this scheme, the Marconi Company is already engaged PRELIMINARY MEASUREMENT 2SQ86 METRES 2 SAYS TAKEN AT £217 FT RAOius POLAR CURVE, SOOMIN. A POLAR CURVE OF A RADIO BEAM Showing how the radio wave travels out from the station in a beam instead of being broadcast in all directions on a 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. In addition to the wireless stations the Company has been operating on these services for some years, it has a beam station nearly completed at Dorchester for communication with North and South America. A corresponding station is also in process of erection at Rio de Janeiro. Another important development in which beam stations are included — and these are already under construction — is the Portuguese scheme for linking up Portgual and its colonies. Some time ago the Marconi Company obtained a concession from the Portuguese Government for the establishment of wireless telegraph stations in Portugal and its colonies for the purpose of linking them together and establishing wireless communication with other parts of the world. These stations are now being built in Lisbon, in the Cape Verde Islands, in the Azores, and in East and West Africa. When they are completed, wireless services will be established with England, with the principal continental countries, and with South America. The beam system is not by any means limited to wireless telegraphy, according to Senatore Marconi. He feels confident that it can be utilized for placing wireless telephony on a much more practical basis than it is on at present, besides helping the systems of picture and facsimile transmission, not to speak of television. Even for broadcasting he believes it will result in enabling programs and speeches to be transmitted to large portions of the United States, Canada, South Africa, and Australia with much greater strength and accuracy than it is possible to obtain by means of the existing broadcasting systems.