IHE RADIO WORLD

Southland Times, Issue 19102, 21 November 1923, Page 9

IHE RADIO WORLD

(By

‘ Regenerater

THE RADIO CLUB. The demonstration in reception advertised by the Radio Club for their last meeting was more or less of a failure owing to the prevalence of static. The operator, Mr Undrill, did his best but conditions were against him. Wellington was the only station that came in with any degree of distinctness. Mr Jordan was engaged in effecting repairs to his generator and was unable to transmit till about 9 ■ o’clock. When he did start, however, he was very clearly received. Members of the club should make a point of coming along this Friday as there are one or two very important matters to be discussed. The lectures will also be of great value to all amateurs. Mr Shaw will continue his series of lectures on practical electricity and Mr C. Roberts will give a lecture on ethereal waves. Mr Roberts is a well known local amateur who has been attending the Otago University for the last year. He- has attended a course of lectures by Dr Jack, who is one of the pioneers of radio in New Zealand and who has great practical and theoretic knowledge of the subject. There can be of no doubt that Mr Roberts’ lectures will be of unusual interest. SPARKS. The hot, muggy weather experienced haa been far from a boon to radio amateurs. Static has been extremely bad, preventing any coherent long distance reception. The growing efficiency and sphere of usefulness of marine wireless equipment closely concern all who travel by the sea or are commercially interested in shipping, and a special exhibition is being prepared by the Marconi Company of the latest developments of the wireless service for ships. From the time when wireless apparatus was first installed on ships, one of the most important functions has been the safeguarding of life, and the Marconi Company, by means of the installation for ships' lifeboats, pow seeks to increase the measure of security which wireless already affords. The Guardian, Sydney, has arranged with the Sydney Broadcasting for a wireless news and entertainment service, which is to start within a few days. It will probably embrace the whole Commonwealth. The service is free, and will be conducted by experts, and it is calculated that it will break the monotony of the long evenings in the backblocks with the best entertainments available. On Tuesday night Mr Arundel conducted the first transmission from 4YO, says a Dunedin exchange. He announced that he had hoped to carry on until some definite arrangement was in hand, but now found he was compelled to shut down. He appealed to those listening-in not to allow the broadcasting to fall through and emphasised the fact that only by united effort could the service be continued. To enable a permanent broadcasting service to be inaugurated Mr Arundel has offered to hand over his whole station and also the equipment for broadcasting from theatres, churches, ete., provided 200 citizens would advance £5 each. He further offered his own service free of charge, until arrangements could be completed. The station would then become the property of the city, and the annual subscriptions from listeners would provide funds to keep the station in operation. A certain portion of the annual income could be set aside for the purpose of paying off the initial capital advanced, and the plant would finally become the property of the listerers-in, and each owner of a receiving set would have a say in its operation. Mr C. J. B. Norwood, of Wellington, has recently imported from America for his son a 3-valve Kennedy set, which tunes from 150 to 23,000 metres without the necessity of changing the coils. It is enclosed in two cabinets, and embodies the Armstrong feed-back Radiotron detector and two 201 A circuits. The valves used are a UV2OO Radiotron amplifiers.—‘Dominion. Patea has discovered “gramophonic” wireless (states a newspaper). A local enthusiast of wireless in this centre was entertained recently to a concert, when the use of earphones was not required. “Wonderful!” was his comment, but his subsequent remarks, when he learned that this latest local contrivance was a muffled gramophone in an adjoining room, are unprintable. The hoax was neatly carried out, much to the disgust of the enthusiastic “listener-in.” By this time, no doubt, all users of Hertzite crystals have realised that it is only possible to obtain maximum results by employing a very fine tentacle. There is, however, one great drawback with the very fine wire, that of the contact being disturbed by accidental knocks or vibration from various other sources. The difficulty can be overcome by employing a bunch of fine wires, so that if one solitary wire become misplaced, one or more of the others will remain in operation. This method has the additional advantage of simplifying matters when “finding points,” and it is also very stable when once adjusted. Theoretically, it can be assumed that several sensitive “points” are engaged simultaneously, and as the multiple tentacle has a natural tendency to reduce the resistance, it follows that the signal strength is greatly improved. There appears to be a likelihood of broadcasting being established in Italy. According to the New York Tribune, “the walls of opposition which thwarted every radio plan has been demolished by the Fascist Government. .4 company has undertaken to establish a broadcasting service, and to pay a tax to the Government for the necessary authority. It is proposed that funds be raised by taxing the subscribers, but this important point does not appear to be quite clear. The Government tax on amateur transmitting sets will vary according to the power of the set. The use of colloids for purposes of wireless detection and amplification is discussed in a recent issue of the French Radio-Re-vue. Apparently colloidal solutions—or suspensions—were first used by certain French experimenters for detection, but more recently a German, Nieuhold, has adopted them to the purposes of low-frequency amplification. A correspondent, Suprin, vicepresident of the Rochelais Radio Club, points out that the chief interest attaching to such a colloid-cell would be the absence of any low-tension battery, and also the possible reduction in the required anode voltage. He considers it essential to obtain a colloid suspension in a non-electroly tic medium, this condition being difficult to obtain, for the colloidal state is usually obtainable in media which possess, in a greater or less- degree, the power of ionisation; a substance actually employed by him was colloidal silver. if using your wireless receiving set, you notice considerable variations in sensitiveness for reception, and these variations, of I course, are generally due to alterations in I the adjustments of the instrument. But ! it is not generally known that the human ear may vary considerably in sensitivity from day to day, and some, at any rate, of the variations experienced with the set, particularly on feeble signals, may be due to this cause. According to the Journal of the American Medical Association, Professor Martin Gildcmeister, a German doctor, has found that the acuteness of the hearing depends very much upon the health. This shows itself by alterations in the upper limit of audibility; on “good” days an observer may be able to hear notes as much as 200 vibrations per second higher in pitch than on “bad” days. The French Navy Bureau of Research has been experimenting to find out whether a jet of sea-water, projected high into the air, can be used as a wireless aerial. The water was drawn by means of the ship's j pumps, and the column of water was con- , nected to the radio apparatus in lieu of , the ordinary aerial. Used in this way, . transmission was effected over a distance of J about eight miles. This water-jet is much f less efficient than the metal aerial, and it is < not contemplated to substitute it for re- I < gular use. The purpose of the experiments | / is to find some form of substitute which i i

could be used in an emergency—for example, when the ordinary antenna had been shot away.