RADIO AND ITS RECEIVERS

Sun (Auckland), Volume I, Issue 279, 15 February 1928, Page 15

RADIO AND ITS RECEIVERS

NEWS FROM IYA A persistent rumour has it that Mr. J. Orbell, B.E. (Elect.), A.M.LE.E., who has been engineer in charge of station IYA, has tendered his resignation to the Broadcasting Company and it has been accepted. Things seem to be on the downward trend again, as Mr. Orbell is the only engineer in the company who can correctly claim to be a radio engineer, i.e., a man who is fully qualified in electrical engineering and physics, and has had overseas training and experience on the high frequency side of electrical practice. Mr. Orbell has been away on holiday and his place has been filled by a New Zealand Broadcasting Company engineer, who must take the blame for the recent poorness of the transmission. The volume has not been steady and a lot of parasitic noises have been manifest at times. Worst of all is a most decided double hump in the transmission, giving much broader tuning. Rumour, lying jade though she be, also hints at other changes in the staff. These changes in staff are a great pity, as it takes a man some little time to pick up the technique of his work, and while the patient (?) listener waits and hopes, he no sooner gets into his stride that someone else comes along, and the listener, who is now rather fed up, has to go through it all again. This is in a nutshell the history of station IYA. RACING BROADCASTS IYA in some way or another, most likely through the popularity of its station director, still manages to be able to put on this most popular sporting relay. In the South the racing authorities are becoming adamant in their demand for payment for relays, otherwise no relays, and no relays they are getting. Now, to the writer’s small experience, the racing authorities are amongst the most generous of all bodies in their catering, within their power, for public needs. Something outside our general knowledge must account for this change of attitude, and it is up to the Broadcasting Company, if the reason lies with them, to put this matter right. Rumour again is quite persistent in the statement that there will be quite a number of licences not renewed this year, by reason of the little consideration paid to the complaints of the unsatisfactory nature of the service. SOME NEW USES FOR THE RADIO VALVE In various branches of applied science and arts the receiving valve is being applied in an increasing number of ways. Among the well-known uses are in various amplifiers for speech currents, as in telephone repeaters and gramophone attachments. New uses number amongst them systems of control in big electric generating stations, controls of street lighting systems, and the latest, a boon to motor-owner and motor-car thief alike, an attachment by means of which the car may be started by the wave of a hand. HOW BROADCASTING “PULLS” Every day evidence grows that broadcasting stimulates interest in entertainments of every sort, increasing the attendances. The Australian National Games, for example, just concluded, as a preliminary to the Olympic Games, attracted record attendances, a contributing cause being the fact that the games were the subject of many broadcast talks. The same applied to the big athletic fixture at Manly, th e attendance being easily a record, due, to a large extent, to the fact that much publicity was given to it over the air. Mr. J. C. Allison, organiser of the Olympic Federation, and Mr. J. S. W. Eve, secretary; Mr. >L,es. Duff, secretary of the Amateur Swimming Association; and Mr. Harold Baker, the international boxer and footballer, have all been heard by thousands “over the wireless.” ON TRAINS Compact transmitting and receiving sets have been evolved in America for communication between each end of trains. The equipment is housed in the engine and the “caboose,” or guard’s van, and is entirely self-con-tained in steel boxes. Two systems have been tried out —simplex and duplex. The simplex system consists of an arrangement whereby the pressing of a button changes the outfit from a transmitter to receiver, or vice versa, the conversation thus being one way only at one time. With the duplex system simultaneous conversation both ways is possible. This is more complicated, however, and at present the simplex arrangement is being used. Loud speakers or telephones are used, a loud whistle being the signal to attract attention. The exact use of the contrivance seems rather obscure, as does also the reason why an ordinary telephone circuit cannot be used from one end of the train to the other, which, as the wireless transmission is subject to interference from iron bridges, cuttings and so on, would apparently be more satisfactory. However, several railroad companies are now using it. WIRELESS WONDERS “A theatre of wireless wonders” was one of the attractions at a radio exhibition held recently in Chicago. Machines were demonstrated which made accurate measurements of distances like one ten-millionth part of an inch. Rays of “cold heat” were transmitted in a beam, and blocks of ice melted in front of the audience, and a visible stream of electrons was precipitated at the rate of 150,000 miles a second. There were also amplifiers which built up sounds to millions of times their original volume, allowing

flowers actually to be heard growing! Wireless beams were also sent out which froze the flowers into brittleness, so that they crumbled in the fingers. This juggling of atoms, including their measurement and velocity, forms a big part of radio research. NEW LINES The following details of two new lines have been sent to us from a totally unreliable source. As the apparatus concerned has not been received for test we should not dream of commenting on its performance. A PORTABLE EARTH This accessory, which is long overdue, has at last been put on the market by Messrs. Mould and Co. It consists of a red clay pot similar In appearance to a flower pot except that it is fitted with a carrying handle. It is fitted with best quality grade A “earth,” in which is embedded a small copper tube with a terminal for connection to the set. It is, of course, designed primarily for portable receivers, but it can also be used for growing rhubarb or hollyhocks. NOVEL RECEPTION Last Sunday evening many picnickers walking along the Lyttelton wharf, returning from Corsair Bay, were amazed to hear the strains of a church organ, arising as it seemed from the sea. The mystery was solved when a loud-speaker was seen on ehe deck of a small Timaru fishing smack tied alongside the wharf. This impromptu broadcast attracted many listeners, who heard the church service and following concert programme under novel conditions. RADIO VISION Regarded not so very long ago as something beyond the ingenuity of the cleverest engineers, television now is probably in that phase which telephony had reached when we first strained our ears for the faintest intelligible whisper, and when music by wireless came very near to being the eighth wonder. That was six years ago, which in view of all that has happened since is a brief period; but there is no reason to suppose that television will take that time to develop, for it is. after all, but another angle of broadcasting. Three-quarters of the way to successful television been paved by the progress made in ordinary radio services. Although similar in many ways, television must not be confused with the transmission of still pictures. This is comparatively simple, and if not a regular occurrence, the transmission of topical photographs between America and the Continent is by no means unusual. These represent the first commercial use of wireless pictures of any sort. The popular—and probably the ideal—conception of radio-vision consists of a contrivance resembling the broadcast set, showing in the ht>me—and they would be sufficiently inexpensive to enable every home to own one—a picture about two feet by three, complete in every detail. The sounds from the scene of action, whatever it might be, would of course synchronise with the picture, making a perfectly natural visual and audible reproduction. A slice of real life, as it were, could be cut practically from anywhere, and transplanted in the homes of a million people. But television may develop along different lines. English experts suggest that it may at first become an adjunct to the cinema, when any event of importance would be televisioned to the audience. Thus, for some time, until the apparatus came within reach of the average pocket, it would be simply an addition to the picture theatre. The ability to introduce the outfit In the home, however, must be the final test of its popularity, and messages from America indicate that television apparatus, which will be accessible to everyone, has been completed. Fireside radio-vision is a fact. HOW IT IS DONE Much of the gear used for ordinary receiving purposes is used in transmitting pictures. Broadly, it can be said that, whereas in sending sounds, variations in the pitch of the vdice or music have to be impressed on the ether waves, in transmitting pictures variations in depth and colour have to be superimposed on these waves. “Photo-electric” cells, discs revolving at terrific speed, letting on to the screen in some instances over ten million dots of light per second, all Lake their part in the television outfit. Of these the photo-electric cell is the most essential, and perhaps the most interesting. When an electric current is allowed to flow through it, the , slightest variation in the light thrown on to the cell shows itself as a fluctuation in the flow of electricity. In this way the light and shade of the scene are converted to definite pulsations in an electric current, which is exactly similar to the transmission of sound. Practically all the men who have carried out experiments in television— Francis Jenkins, an American; J. L. Baird, an Englishman; and M. Boulin, a Frenchman, have followed these lines in their quest for an equipment nearing perfection. Soon, in all probability, the amateur will make his radiovision outfit at home just as he does now his single valve set. THE NEUTROBLOOPODYNE The Dunn-Browne Radio Corporation, the makers of this remarkable set, claim that it will bring in every signal “on the air,” whether it is wanted or not. It employs 17 valves in all; seven as H.F. amplifiers, one detector, and nine L.F., the last one being of the “high u” type. Both H.T. and L.T. current (the former amounts to about 3A as no grid bias is employed) are supplied by dry batteries, and a gramophone turntable is provided for the electrical reproduction of gramophone records. This is driven by a sturdy little two-stroke engine which will run for ten days on an eggeupful of petrol. Its speed is controlled by a small vacuum-assisted brake, while provision is also made for playing records backwards if desired. All this equipment, together with horn loud-speaker which cuts-off at 350 cycles, is built Into a cabinet about the size of a large bookcase, and fitted with an extra-strong carrying handle. CORRESPONDENCE Valve.—You can test whether your set is delivering energy to the aerial by moistening the finger and touching the aerial terminal. If a distinct “plop” is heard in the phones, the set is causing interference. G.D.H. Manurewa.—As you have tried most of the four-valve sets which give really good results, and others are merely slight alterations which are hardly worth building if distinct variety is desired, I would suggest a try at the new shielded grid four-valve set, as described in detail in “Modern Wireless” of October and November. The valves should be procurable by now from the Marconi Osram agents, or from the Cossor agents. The children's tonic! Sulfarilla Tablets purify the blood and give them rosy cheeks and bright eyes. Easy to take. Is 6d a box at all chemists.