RADIO AND ITS RECEIVERS

Sun (Auckland), Volume II, Issue 575, 30 January 1929, Page 16

RADIO AND ITS RECEIVERS

Conducted fcr THE SUN fc SYDNEY BROADCASTS | OVER 20 YEARS AGO PROGRESS IN TELEPHONY The majority of people who listen to the broadcast programmes have an idea that broadcasting is but three j or four years old. Their knowledge i of it, either by direct listening or hearing about it from their neighbours, extends only a 3 far back as that. It will probably surprise readers to learn that wireless telephony—that is what broadcasting is—was actually heard in Sydney in 1908. True enough, it must be admitted that the regular services from the stations and the demand for payment of a fee for listening were features unknown before 1923 in Australia. There were not many listeners in 190 S, an<T there was no listening fee; the transmissions were carried out on : Sydney Harbour, and the broadcasting i stations were on two of the ships of! the Great. White Fleet of the United | States Navy, that made the memor- j able world tour during that year. It was, of course, purely an experi-; ment, and the methods adopted dif- j fered from the present day methods j In many respects. In one regard, j however, they had something in com- i mon with present, day broadcasting; | phonograph records were utilised for j the “items.” The transmitters and I the receiving arrangements were very j much in the experimental stage. For , a few years before the fleet left j America, the naval authorities had ! been interested in wireless telephone j experiments, which were being con- i ducted by de Forest, and it was decided to try out the system on a long tour. THE “SINGING ARC” The system of transmission used was the arc—the “singing arc,” as it was sometimes called—just then being developed by Poulsen. a Danish scientist. For a few years previously the arc system was used for telegraph signalling, but as a telephone J transmitter for sending out speech and ; music no attempts were made until j the American, de Forest, took up the ! system. Owing to the fact that no j satisfactory devices were then j known for amplifying or boosting up the very weak impulses produced > ! the human voice in the microphone, the range of transmission was very short. This limitation was also accentuated because the receiving methods were primitive—that is in comparison with the methods known to-day. Consequently the “announcements” and the Sousa band records j were not heard very far from the ships in the harbour. Those were beginnings, however, and they demonstrated that what was needed was more sensitive equipment for strengthening the energy put into the transmitter and picked up by the receiver, as well as a more satisfactory technique for imposing the speech or music energy on the main “stream” of energy developed in the i transmitting station. The next step was not taken until the invention of the three electrode valve or vacuum tube; that device made wireless telephony and its principal application, ■ broadcasting, commercially possible. VALVE ORIGINATOR There has always been some dispute as to the real originator of the valve, or, as it is known in America, the vacuum tube. A careful study of the literature shows that Edison ap- ' parently directed attention to an “effect” which proved later to **e a correct pointer to progress in the de* velopment, but the first valve was made by an English physicist, Dr. Fleming. His valve was a two electrode affair, and was unsuitable for amplifying or boosting signals; this desideratum was attained- when de Forest introduced a third electrode, which he called a “grid,” into the Fleming valve. In the patent courts in later years, however, Fleming was given the credit for the invention of the valve, whether it contained two or three electrodes. The valve came under the most intensive research and development duri ing the war, and shortly afterwards; | and, in 1919, wireless telephony was |on a safe Scientific basis. Experimental transmissions had actually been made before that year. It is recorded that some experimenters broadcast the results of the Presidential election in America in 1910, but the war period put a stop to everything in the way of broadcasting to ] the general body of listeners. And ! those listeners were enthusiastic ama- 1 | teurs who flourished principally in \ j England, America, and in Australia. i | Many listeners to-day remember the ; transmissions carried out on Sunday ! evening in Sydney, about seven years | ago; the usual records. and, later on, !an occasional artist brought before i the microphone in the “studio” in the | amateur’s back room. Mr. Charles j McLurcan, at Strathfield, was the bej ginner in those stunts, and it is no | exaggeration to say that the efforts of j the amateurs in Sydney and Mel- | bourne had much to do with in the inauguration of the broadcasting services as we know them to-day. The first regular broadcasts under the Postmaster-General’s permission were made from station 2BL, and the plant used was the growth of amateur transmitting equipment, and the operators of the station were all from the ranks of the amateurs.

by R. F. HAYCOCK. INDIAN BROADCASTING COMPANY' IN FINANCIAL STRAITS UNAPPRECIATIVE PUBLIC Inadequate resources, poor programmes, and lack of public support j are connecting links in the vicious j [ circle which has encompassed India's broadcasting experiment in its second year. It has been a matter of common knowledge that almost since its inception the Indian Broadcasting Company has been in sore financial straits, reflected in the balance sheet, when a loss of nearly two lakhs of j rupees on the first year's working was j disclosed. Those members of the public who, j in their enthusiasm, had purchased j : wireless sets, were early aware that ; I all was not well by the steady decline j j in the quality of the programme broadI cast from Bombay and Calcutta. The j two fundamental reasons of the present crisis, and the resignation of j the European expert members of the j staff, appear to be that the company i was under-capitalised a.t the start, and ! that broadcasting in India has failed ! to capture the imagination of Euroi peans and Indians. ; At least 25,000 licence-holders are j needed to enable the company to work j efficiently, but the number of licences ! taken out is less than a tenth that | number. Mr. Eric Dunstan and Mr. C. C. N. Wallich, the experts brought out from the British Broadcasting Corporation, have left because, in a nutshell, they are not enabled to provide programmes of sufficient attraction and utility to ensure success on a station programme allowance of 30 rupees a day (£2 ss). EFFORT TO RAISE CAPITAL ! To the credit of all concerned, it can ! be recorded that the present situation ; has come about in spite of a splendid j effort. Early this year, finding that j Indian capital was shy, Mr. Dunstan j was given leave by the company direc- | tors to proceed to London and there endeavour to interest home manufacturers in the financial possibilities of Indian broadcasting. But the mission failed, as did the subsequent attempt to secure a Government subsidy. MUST LOSE THOUSANDS r It was on his return that Mr. Dunstan summed up the future of broadcasting in India. Either, lie said, financiers must be prepared to incur a loss of several thousands of pounds , during the first four or five years of : endeavour, or they must by a miracle . overcome such obstacles as the gene- , ral illiteracy of the public and the ' poverty of entertainment talent in comparison with that available in the ! big European cities. “Moreover, with ) the advance of broadcasting and the : appearance on the market at increasi ingly cheaper prices of elaborate ap- . paratus enabling listeners-in to receive from thousands of miles away, the ’ tendency will be for possessors of wireless sets to tune in to London and Rome direct, -without concerning themselves with an Indian relaying station.”

In spite of these apparently* overwhelming odds, Mr. Dunstan, in Bombay, and, Mr. Wallich, in Calcutta, made a gallant struggle, which has ceased only with the resignation of the exmembers of the British Broadcasting Company, “on a fundamental principle of policy, believing that the sole criterion whereby broadcasting is judged is the programme.” STATIONS WILL CONTINUE

The disappearance of the European staff is not to interfere with broadcasting. Not only will the stations continue to work, but their activities will be extended, declares Mr. F. E. Rosher, a director of the Indian Broadcasting Company. Certain it is that if the curtain were now rung down, the prospects of a revival during the next decade would be negligible. That a great service, with its power of entertainment and education, and potentialities for unimaginable advance, should be lost to the country, •would be deplorable. The directors incline to the view* that rather than that this should occur, the. Government will take an active interest in the company, assuming a measure of control similar to that exercised by the Home Government over the British Broadcasting Company. That seems the only solution of the present difficulty if broadcasting is to survive in India. INSULATED SCREW-DRIVERS Many a valve has been burned out., or battery seriously damaged, by an accidental short circuit of the high tension battery through the valve filament when making adjustments to the components of a receiver. One of the most common causes of such accidents is the use of metal tools inside a cabinet in such a way that the body of the tool can bridge wires carrying the high tension current if it touches them. Whenever possible, the high tension battery should he disconnected when making such adjustments, but in some cases it is necessary to note the result of adjustments on the operation of the reeciver as they are made. The removal of the high tension battery then -becomes impossible. In such cases the risk of damage can be eliminated by using a screwdriver which has been insulated in such a way that it cannot cause short circuits. There are two simple ways of doing this. The first is to take a length of black insulating tape, which is treated with a rubber compound to make it slightly sticky, and hind the metal shank of the screr/driver with it, leaving only the tip of the blade exposed. The rubber binding should then be dusted with powdered chalk to cover the tacky exposed surface of the tape. A more effective and convenient insulation can be provided by obtaining a piece of thin rubber tube about as long as the blade, and slightly smaller in diameter, carefully drawing It over (he blade so that it forms a tight casing. This casing will last indefinitely, and can easily be replaced if the rubber shows any sign of perishing. Quite a. good panel marker can be made from a pen-holder into the end of which an old gramophone needle has been forced.