THE WIRELESS WORLD.

Otago Daily Times, Issue 19020, 16 November 1923, Page 2

THE WIRELESS WORLD.

(By Mauna Vox.)

NEWS AND NOTES.

[ltems of news, comment, suggestions, ' etc., will be welcomed by "Magna Vox "1 I On Tuesday night Mr Arundel conducted i tlie final traiusniission from 4YO. lie an- 1 no-anced that he had hoped to carry on [ until some detinito arrangement was in i hand, but now found he wa s compelled to shut down. Up appealed to those listeningin nor. 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, etc., provided 200 citizens would advance £5 each. lie further offered his own services free of charge until arrangements could be completed. The station would then become tlie 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 listeners-in, and each owner of a receiving set would have a say in its operation. A regular service could bo inaugurated on (lie following lines:— 6 p.m.—News summary. This would include late announcements of local and general interest, sporting results, and correct, time. 6.15 p.m.—Market reports; latest sale prices for fruit, grain, produce, etc. 6.45. —Weather forecast and weather information for farmers 7.0 .News summary as at 6 p.m. and sporting results. 7.li>-7.30.-~-Selected musical items. Two or tliree nights weekly this schedule could t-e extended as below. 7.30-7.*5.~-Children's story. 7.45-8 p.m.—Announcements. C-9 p.m. —Concert programme. 9 p.m.—Lecture or instructional talk on subject of general interest. 9.50-10. —Dance music and orchestral selections. tO p.m. —Late news and sporting results. 'J hero is no reason why there should not be such a broadcasting service in Dunedin. and if evoiy listener would only do his share while there is an opportunity the scheme could be set in operation immediately A.G. writes as follows:—"Now that Mr Arundel has closed down it seems to me finite possible that Mr O'Neill will do likewise unless something is done to assist in the work he is carrying on. It is perhaps j no! generally known that Mr O'Neill { .broadcasted at regular intervals to the Hospital and Benevolent Institution. Apart from this, however, it is only fair that the "listeners in" who have enjoyed many fine concerts from 4YA should contribute something to the upkeep of the station. Another very good reason also—one which concerns "listeners in" most, I should think--is that many will have to put away their sets if 4YA closes down. So it is in the infeie.sts of possessors of receiving sets not to allow this to happen. The Radio Club will have ns itwdi as it, can do to carry on with the limited finances at pre- I sent at its disposal, but this obstacle can be overcome if all 'listeners in" will do their part end pay the subscription which will be asked of those who are interested j in wireless. There is an old saying. "You never miss the water till the well runs dry." Dunedin listeners should rise to the occasion before it is too late. THE KEFLEX RADIOPHONE. j The recent articles dealing with one-valve 6ets gave a fair idea of what is possible with a one-valve set of the right kind with a. good circuit. Many New Zealand amateurs are receiving California, Honolulu, and American concerts, but I have seen only one set which is capable of this—the Reflex Radiophone. V great advantage of this set is that it can be used with either inside loop aerial <>r outside antennas. The extreme simplicity of operation and the elimination of extraneous noises and super-sensitiveness mane an unusual reception range possible. Lsing the outside loop aerial, this set receives broadcasting stations up to 800 miles when a loud speaker is used and Up to thousands of miles when 'phones sir;; used. Numerous Transcontinental receiving records have been made w-ith this %et. which has a wave length range of from 2ut) to 500 metres, and adjustments may be mado in the- set which will enable it to receive longer wave lengths. The circuit is a combination of radio and audio frequency. The signals are first passed through the three tubes at radio frequency. The amplified radio frequency signal is rectified in a crystal detector, and the rectified signal is "reilexed" through the last two tubes at audio frequency, and the signal is then conducted to the head 'phones or the loud speaker. The result is five stages of amplification with three tubes. The crystal detector is used to rectify. 'I he signal is the result of years of experiment, and it has proved itself ideal. The adjustment knob which projects through the centre of the panel is designed so that, it is shock-proof and will remain in adjustment through any shock less severe than one which will endanger the tubes themselves. The use of the crystal detector tor rectification ensures reception free from distortion and all extraneous noises. Prevision is made so that the antenna and ground may be used in conjunction with the loop if desired, which gives increased signal strength. The antenna should never exceed 50ft in length. Regulation of signal intensity is accomplished by means of an "A" battery potentiometer, and the. use of a directional loop eliminates interference fiom practically all stations not in the direction towards which the loop is pointed. This greatly reduces the effect of static, which'is now known to be directional. By the use of a vernier condenser separate stations, tuning only a fraction of a degree apart on the condenser dial, may be brought in A grounded shield is also required to eliminate all body effects in tuning. The whole reflex outfit mav be packed in a porlmaateau, and the loop is collapsible. If low temperature valves are used a couple of dry cells make an ideal "A" battery, DIRECTION FINDING. The New Zealand Shipping Company's steamer Remuera is probably the first commercial vessel to visit New Zealand equipped with an up-to-date direction-finding plant. It will not be lomr before most of the large oversea liners will be similarly equipped. To the layman the apparatus presents a complicated mass of switches and terminals, but to the wireless man it is full of interest although much practice with the instruments "is required to obtain perfect results. The circuit, employed with the loop aerial consists of six valves divided into four steps of radio frequency amplifications, followed by the detector circuit, after which comes one stage of noli-magnification. A very interesting device is the goniometer, which is the principal tuning device, and the, dial is so arranged as to represent o compass. When a certain degree of coupling brings in maximum signal strength, a reading is taken from this dial, and is nlotled on a chart. The position of a vessel is then calibrated. The receiver covers a range of all commercial wave lengths, and is u«ed a great deal in English and American walet's. . ... This particular installation is supplied and controlled bv the English Marconi Company The company is installing one on the TiiiaVehu. which will be the next vessel to visit Auckland equipped with this device for assuring safety at sea. WIRELESS WAR. A now honor of war is foreshadowed by the experiments of the. Germans in wireless lnle.lv. aimed nt the development and perfection of a new wireless ray or beam which will concentrate the naves on a given point. If thev can achieve it they will be in possession of what one. might call an enormous invisible "gun." which will provide e form of "artillery" far more deadly than has ever been conceived before. From some vast transmit ting station a beam will be aimed at some city in an enemy country it wa» desired to attack. The power wave would be so controlled that it flowed constantly in this one path, and in this one path alone. Then along this definite wirele--« ray would be sent rushing a stream of ltirt.il-nulleil. pilotless "flying bombs." The beam would supply the power for their motor, and when they came to the point in the sky exactly above the city they intended to destroy, there would be a means of stopping their machinery automatically, and permiUinsr them to fall, with their loads of high explosive or incendiary material, in a constant devastating stream. That is the theory of the aeronautical authority of the Daily Chronicle, and having in mind the wonders aelreved in the past war who shall denv that, fantastic as it would have appeared 10 years ago. it has not the foundation of practical application in ii'i