Radio Broadcast (May-Oct 1922)

100 RADIO BROADCAST House of Commons recently, the PostmasterGeneral said that experimental transmission had been commenced between the two stations and as soon as the preliminary trials were completed a public service would be inaugurated. The Leafield station had been working satisfactorily for some months, and its messages were regularly picked up practically all the way by liners on the Australian route. The total cost of these two stations was estimated at well over $1,000,000. The cost of the remaining stations of the Imperial Chain is estimated at well over $4,000,000, but without provision for patent royalties. Some Applications of the Vacuum Tubes PROBABLY no piece of electrical apparatus is so adaptable to a variety of purposes as the three electrode vacuum tube, and this with little or no modification of its construction. This wonderful adaptability is well illustrated in the high-speed transmitting and receiving equipment recently described by Lieut. -Colonel Cusins in his paper before the Wireless Section of the British Institution of Electrical Engineers. The transmitter and receiver contain together eleven tubes, which have, between them, eight different functions to perform. Of the two in the transmitter one is the main highfrequency generator while the other acts as a variable control resistance in its grid circuit. In the receiver, three serve as a radio-frequency amplifier, one as a tube relay, one as an audiofrequency generator, one as a tube-relay control valve, one as a direct-current amplifier, and two in conjunction as a double-current valve relay. Although the paper described the progress made in what the author called the mechanicalization of wireless telegraphy, this progress is only made possible by the elimination of mechanical links, except at the beginning and end of the chain, and their replacement by three-electrode vacuum tubes. Radio Telephones on German Railroads WHILE the idea of using radio telephones on railroads is not altogether new, all previous attempts along this line have not proved successful, for the simple reason that no suitable form of wave generator was available, and the receiving equipment was relatively crude. Now with the vacuum tube available for receiving and transmitting, it becomes possible to utilize radio telephony for railroad purposes. It is reported that several German express trains are to be equipped with radio telephones to provide communication between the passengers and hotels and stations. Radio Telephony in Sv^eden THE telegraph authorities of Sweden are now conducting experiments for linking up the ordinary telephone with the wireless telephone so as to enable through calls to be effected. This scheme of using radio links, as radio telephony is called when employed in conjunction with regular telephone systems, has been tried out in the United States with promising results, and there is a radio link connecting up Santa Catalina Island with the California mainland in everyday operation. Northern Africa Radio Station THE building of the radio station at Ain-el-Hadjar, near Saida, on the railway line from Perregaux to ColombBechar, has just been started by a detachment of military engineers. The station, which will be the most important in North Africa, is intended to form the radio link between France and her African colonies, and in case of a breakage of the submarine cables to undertake the forwarding of telephone messages between France and Algeria. Radio Service for British Columbia THERE has been estabHshed at Vancouver a radio telephone service for British Columbia, interior and coastwise, and for deep-sea ships as far as 2,500 miles at sea. It is planned to give the world news, concerts, and speeches to distant parts. The tests have been successful, and the station is now in regular operation. When Wireless is Better than Wires ESTABLISHMENT of radio stations at Stewart, Atlin, and Alice Arm, in British Columbia, and Dawson and White Horse, in the Yukon, will be urged upon the Canadian Government by Frederick Stork, member-elect for Skeena Riding. According to Mr. Stork, the cost of installing radio would be very small compared with the amount required to put the old telegraph line in shape, and would insure a service that would be in operation at all times.