ACROSS-THE-WORLD WIRELESS

Dominion, Volume 12, Issue 228, 20 June 1919, Page 10

ACROSS-THE-WORLD WIRELESS

KAROOLA'S ACHIEVEMENT PICKS UP NORTH SEA MESSAGES OFF AUSTRALIAN COAST Tho cablegrams of a few days ago reported the astonishing fact 1 that tho steamer Karoola, whilst off the northwest const of Australia, picked up messages quite clearly'from an English station in the North Sea, the messages having been transmitted on the ordinary short range wave length of GOO . metres. This was made possible by the fact that the steamer's wireless equipment included tho Fleming valve detector, which enables messages to be picked up (not sent) over almost any distance this sphere can offer. Tor instance, there will never be-any .difficulty now in picking up messages from the Antarctic. So long as explorers .have a low power plant to send out the }messages there Will not be any trouble in picking them up with the Fleming electronic valve. /When Mr. E. T. Fisk, manager of th« Amalgamated Wireless in Australia, was in England in 1910 (says the .Sydney "Sun"), this new detector was being developed, and lie was told that Signer Marconi and one of his assistants wanted to come to Australia to seo if by its means they could get signals direct from the trans-Atlantic stations. But neither of them could leave, for.they were both engaged'in important war work; and so it came about that Mr. Fisk said he would try what ho could do. On tho basis of Fleming's detector ho had to design a complete receiver. Ho had to experiment and modify enormously before he could get the thing perfectly carried out, but in the end he got it, and that is why the Karoola was able to pick up those long-distance messages the other day. Mr. Fisk worked on tho idea, continuously for about eight months. During that time he had test signals from the Carnarvon station in Wales. Having succeeded in tho design, his next concern was to see if tho new receivers would be turned out in quantise in Australia. In that also ho has been most successful. It is a thing worthy of note that the electrical machinery manufactured at Wireless House is ail made by Australian workers. Much of. it demands the most confidbnt and delicato craftsmanship. But Mr. Fisk has not imported one worker since he came out in 1910. Ho has trained tho whole staff. Ho says that, the work is as well done as any men could do it. Ho lias had an order for 25 of the now receivers from the Commonwealth Government, Aush'alion shipowners, apart>from tho Government havo so far ordered about 80. Others have l>cen exported, some of them to the Marconi headquarters; Orders are coining in from New Zealand. Presently a modified type of the new receiver will he produced for use in aeroplanes. At present very few aeroplanes can receive messages, though many can transmit them.

The chief effect of the now Magnifying Valve Receiver is that it makes the messages more audible—magnifies the sounds. Many different types of magnifying valves have been produced, each tyne having different characteristics, and valves are used in'many different types of circuits. The great aim of. .modern designers is to produce n complete magnifying . valve receiver, with valves of such a type and circuits so arranged as to obtain the greatest possible sensitive, ness, combined with simplicity in operation, stability of adjustment, and continuous work on any given adjustment •without trouble.

If this combination is not Rood any advantage which, might lie obtained in the way of sensitiveness is almost entirely destroyed bv flic difficulty of adjustment by instability and consequent loss of signals in the middle of important messages. Such troubjes are almost invariably experienced with "valves which use low iwtentinls in the plate circuit, and again in circuits which attempt to impose a number of functions on one valve. In addition tx> this there are numerous other points in the dteign and construction of complete receivers requirinir careful experiment, and special knowledge. '

There U no need ,to labour technical details. What the average man needs to know is that in this mutter of electrical machinery, ns in other matter*, Australia nan confidently compete • with the rest of the world, ■and.on occasion load the way. The achievement of the Karook, which is the achievement of the new receiver, marks an epoch in the history of wireless. y