RADIO RECORD

Greymouth Evening Star, 30 August 1934, Page 4

RADIO RECORD

NOTES FOR LISTENERS-IN

( By

“Reception”)

ELECTRICAL MUSIC.

VALVES AS ORGAN PIPES For some years it, lias been the aim of many investigators to provide musical instrument in. which the necessary range of notes is produced purely by electrical means, that is, without the use of pipes, strings, reeds, or any of their equivalents, which have always been considered necessary for the purpose. As a result many forms of pipeless organs, electronic organs, and other instruments to which such names as “Emicon,” “Sperophone,” “Hellertion,” and “Trautonium” have been applied, have been created. Some of them have met with considerable success, and have been used for providing ’programmes for broadcasting stations in Europe (writes N.M. Goddard, 8.E., in the “Sydney Morning Herald”).

Perhaps the largest and most successful electrical instrument is the electronic organ, which has been installed at the French broadcasting station “Poste Parisien,” and which is well known throughout Europe. It was designed by M. Givelet, and has been built by Coupleux Freres, of Lille. In this instrument there arc three manuals, each of four and a-half octaves, and pedals, which provide a further two and a-half octaves, the whole combination giving a choice of about 200 notes. There are 95 stops, including couplers, and the output, which is entirely supplied by electrical apparatus, is delivered from a bank of 13 loud speakers.

To produce each note a three-elec-trode valve is provided, the frequency of the oscillations, in each valve, and consequently the pitch of the resultant note being determined by the values of a fixed condenser and an inductance or choke with an iron core, which are .included in circuit with the valve. ’Tuning of each valve circuit is effected by moving the position of the core of the inductance. The oscillations produced by each valve and its associated apparatus when its key or pedal is operated are amplified, for which purpose each note-producing valve has an amplifying valve coupled to it. The whole assembly, therefore, has the somewhat complicated arrangement of above 400 valves, plus their filament and plate current supply circuits and other associated apparatus. The manner in which the tone quality of each note is determined or varied to give it, for example, a trumpet tone or a flute tone is interesting. The fundamental waves produced by each Qscillatory valve circuit are normally accompanied by a great number of harmonics. Operation of the stops of this instrument introduces into the circuit filters ■ of various characteristics which remove varying numbers of these harmonics, the result being a variation of the quality of each note according to the degree of removal of the harmonics. Taking into consideration its range, the instrument is extremely compact, as apart from the console, -which is similar to that of any organ, the rest of the apparatus, excluding the loud speakers, can be housed in a rack about 10 feet long, six feet wide, and about a foot deep. It is only natural that an instrument such as this should be subjected to a good deal of criticism. Some of its critics admit that the instrument is a remarkable piece of mechanism, but ask why it should be called an organ, contending that it is impossible to reproduce true organ tones by any means other than an organ of the generally accepted type with its pipes and technique, which have been gradually developing through the centuries. To this its builders reply that for 60 years they have been constructing pipe organs. and that, in common with organ builders the world over, they are jealous of their reputation, and that unless they had been entirely satisfied with the possibilities of the instrument they would never have allowed their name to be associated with it.

Whether this particular instrument is truly an organ or some new kind of instrument, which so far has not been christened, is a matter for musicians to determine, but it has some good features, such as case of control and the ability to deal with compositions hitherto found unsuitable for pipe organs, as well as offering opportunities for the development of new effects. It is also a brilliant example of the infinite possibilities of the thermionic valve, which, having made broadcasting and long-distance landline possible, is extending its influence in all directions. Some day it may provide instruments which may give passably good imitations of symphony orchestras and like combinations, in which case some of the difficulties of picking up the performance for broadcasting, which were so apparent recently. may be removed, for the Poste Parisien instrument can feed its electrical output directly to the transmitter without the necessity for converting it into sound.

RADIO AT OLYMPIA A miniature wireless station was used at the International Horse Show at Olympia this year to provide rapid means of communication between the judges in the arena and the awards oflice and the announcer’s office, both of which were behind the crowded stands. Ln previous years, the judge’s decisions were conveyed to the officers by runners, who hurried on foot from the arena, covering several miles each day. Standing beside the judges was an official with a small microphone in his hand and carrying on his back what looked like a small haversack with a rod about 3ft long protruding from the top. The “haversack” contained ultra-short wave transmitter by means of which the decisions of the judges were immediately telephoned to the offices at the other end of the exhibition building. This enabled the announcer controlling the loudspeakers to make the results of the judging public even before the rosettes were presented to the prize-winners. The transmitter working on a wavelength of 5.75 metres, incorporates one valve working at an anode voltage of 120, the power to the anode being .35 walls —less than that consumed by an ordinary pocket lamp. The transmitter hox measured only 11 inches wide, 15 inches high, and 41 inches from back to front. The receivers were of the super regenerative type, one incorporating three and the other four valves, and operated with small rod aerials.

WIRELESS ECHOES.

PUZZLE FOR PHYSICISTS A world-wide “trap” is being set by scientists- in an organised effort to solve the mystery of long-delayed radio echoes, says the “New York Times.” Just as an echo resounds from some natural sounding-board such as a cliff or gorge, so these ethereal reiterations register several seconds after the direct signal is heard. Lapses between the signal and the echo have been sufficiently long in several instance to lead, radio experts to estimate that the secondary waves came from beyond the orbit of the moon. Science is anxious to clear up the mystery or to’ find some way to overcome the reverberations, because in television these freak antics arc more annoying than in wireless. In television the echo becomes “a ghost.” After the main image flashes on , the screen faint duplicates or “sprites” of the same figure appear a second oy t wo later.

Senatore Guglielmo Marconi on his visit to New York last autumn told of intercepting round-the-world echoes. He said he had observed at least seven echoes on the globe-girdling short waves. It will be recalled that radio waves travel around the earth seven and a-half times in a second, at the speed of sunlight, so that only fractions of seconds separate the primary signals and the echoes. Marconi explained that he had recognised short words such as “no” after they had spread around the earthly sphere more than. once. It is difficult, however, to understand longer words after two globe-girdling flights, because the echo is back at the point of origin before the last syllable of a long word is uttered.

The .phenomenon of these round-the-world echoes is not as puzzling as those that come back'from interstellar space. What reflects them? That is the question. The elusive signals apparently penetrate the Heaviside surface or “radio mirror” at high altitudes or, finding a hole in it, escape into outer space, only to be reflected back to the earth.

WHERE TO TUNE Dr. J. 11. Dellinger of the Bureau of Standards is in charge of the investigations now being conducted in this country in co-operation with European observers. Short-wave set owners, especially those who understand the wireless code, have been invited to eavesdrop on special signals being broadcast from England and Switzerland. Station GSB, Daventry, England, transmits a 1000-cyelc note on the 9510-kilocycles channel on Sundays, Tuesdays, and Thursdays, and Station HBL, the League of Nations transmitter at Geneva, broadcasts on 6675 kilocycles on Sundays, Wednesdays, and Fridays. The signals from these powerful transmitters consist of a five-minute tuning period followed by the wireless alphabet, each letter spaced by a oneminute interval. The trick in “Trapping” one of the elusive echoes is to check the lapse of time between the main signal and the echo. IL calls for quick work and a stop-watch. “Long-delayed echoes are a baffling phenomenon,” said Dr. Dellinger. “It has been verified in a few scattered observations by Dutch, British, and French engineers. Echoes have been heard from one to thirty seconds after the emitted signal. Not enough is known, however, to determine what causes the echo signals or how they are propagated. “Listeners in all parts of the world have been enrolled in this endeavour. No Technical training is required. More than 10,000 observers have been enrolled in Great Britain.” There are various theories advanced to account for this strange repetition of signals. Dr. Carl Stormer of Oslo University, Norway, who is noted for his observations of wireless echoes, suggests that there arc streams of electrons lurking thousands of miles from the earth’s surface. The radio echoes, according to the Stormer theory, are reflections from the electron streams or “curtain.” The idea that the retarded signals are caused by interference of the radio waves in the earth’s atmosphere has been generally abandoned. It is pointed out that if this theory were true some of the signals would have travelled from twenty-eight to one hundred times around the earth, because from four to fifteen seconds elapse between the first signal and some of the echoes. Encircling the globe one hundred times seems impossible, because in such a prolonged flight the waves would have become so weak as to be imperceptible. Therefore it is believed the echoes returned from the outer space. There is no “wall” in a material sense that throws the echoes back, according to Professor Stormer. He believes the “wall” is a barrier caused by collision of electrical waves from the sun and the magnetism of the earth. Then, according to his theory radio waves which, escape from the earth’s atmosphere and penetrate Ihe upper regions in the lower latitudes strike this “wall” and are echoed to the earth.

HIGH LICENSE FEE Australia has reduced, or proposes to reduce the annual license fee to be paid for the operation of a receiver, a gesture of the Government that will be hailed with delight by hundreds of thousands, and should earn the reward of a marked increase of licenses. This decision leaves the New Zealand payment at almost 50 per cent, greater than its neighbour’s, and there is the prospect of a very strong agitation for reduction springing up. There are many sound arguments Io support this agitation; there, may be equally sound ones against' it, but the board has failed to make them in its one great opportunity—its annual report. Hud that report contained details of the board’s commitments, its expenditure on various blanches of its work, and its proposals, for future development, it. might have convinced listeners of the need for every penny of its income at. the present rate. But, when listeners see their neighbouring country planning a big programme of powerful relay stations, and replacements of existing ones, undertaking expensive programme work in its innovations of the past

nine months, and at the same time introducing a. reduced license fee, they are inclined to ask, “Where do we come in?” SANGSTER SHIELD. It, is announced that Mr D. K. Woodbury (ZLIGH), of Waenga, Cromwell, has won this year’s Sangstcr Shield contest for amateur radio transmitters with a total of 61 points. This contest was inaugurated in 1927, when Mr’ R. Sangster presented the shield for competition in the Dominion, and since then it lias been won four times by amateurs in the Otago district. As it takes the form of a low-powered contest, it. is actually a test of efficiency for both the station and the operator. Points are awarded for each contact made, and the competition is spread over a period of eight days. Mr Woodbury’s total exceeds those of the- runners-up by thirteen points, Iwo amateurs at Wellington each scoring 18. Station ZL4GH is a portable outfit, and was brought from Gisborne to Cromwell when the owner decided to go into camp there to take advantage of the mining subsidy in Central Otago. The “rig” was rebuilt and refitted many times before being entered in the contest, and other amateurs have given valuable assistance in keeping the station on the air by the loan of batteries and other parts.