RADIO RECORD

Greymouth Evening Star, 20 December 1934, Page 3

RADIO RECORD

NOTES FOR LISTENERS-IN

(By

“Reception” )

FIVE LIBRARIES.

8.8.C.’s GREAT COLLECTION. Th© 8.8. C. have formed three very fine libraries. They have 37,000 gramophone records, 8000 plays, and a collection of music that must surely include every work they could be possibly be called upon to provide. Besides these, they keep a file of all the manuscripts of broadcast talks. The library of gramophone records, although it was started only 18 months ago, is already one of the finest in the world. Its musical section ranges from the great symphony orchestras to the “effects” thfit are used in the production of plays and light entertainments, its operatic selections recall famous voices of the past, Caruso and Melba among 1 bcm; and not only are great singers among the records, but other celebrities, like Sir Arthur Conan Doyle, whose voice we heard again only the other day in the “Scrapbook of 1910,” telling us why he wrote “Sherlock Holmes.”

Though the records number ,37,000, any one of them, can be found in a moment, so complete is the system of cross-indexing under the titles of the piece, the name of its author or composer, and the number of the record. They are all filed vertically, each inside its folder, upon rows of steel shelves.

The music library was started in a very small way some 12 years ago, when the 8.8. C. were at Marconi House. Then it was that a member of the staff collected a dozen or so items and kept them on a shelf over the stove. To-day this library occupies two large rooms of steel shelves.

The main orchestral section, excluding dance music, contains 13,000 items, some of which may have as many as 40 or 50 additional pieces scored for the various instruments. The library supplies al the stations with their requirements for music, and those items that are in special ,request, and they run into some thousands. are duplicated and triplicated. Added to these are 3000 items of military band music. 8000 songs, and some 80,000 vocal scores. Even these figures do not exhaust the list, for there is music for the piano, music for the piano and violin, music for the piano and ’cello, and recently there has been added a number of items for the organ.

The library for plays was started some eight years ago with “Paddy the Next Best Thing.” It. now contains about 8000 works. Only a small nroportion of this number has been broadcast, but thorp they all are. arranged for quick and easy reference, like the music and the gramophone records, always ready at a moment’s

notice in case the producing staff should call for any one of them and wish to adapt it for an evening's broadcast.

WIRELESS AND AIRCRAFT.

CONTINENTAL SERVICES. In the past few weeks it has been shown that if long range and night commercial air services are to become always reliable, wireless equipment of a complete nature is essential. Some of the competing machines in the air race were fitted with wireless, but even so, they were at a loss as, for example, the Dutch aeroplane which landed near Albury. The trouble arose because, although there was equipment both in the ’pilane and on the ground, its combined resources were not fully capable of fixing the position of the. machine accurately and of enabling the necessary information to be conveyed to the pilot quickly. Perhaps the most highly organised air services from the wireless point of view are those which' are in operation between England and the Continent. Part of the apparatus consists of three directionfinding stations in England, which can co-operate in fixing the position of any air liner which may be in flight. The aeroplane sends out signals and the bearings of the incoming signal are taken simultanously at all throe points. Two of them pass on their results to the third, and the operator in charge of the third station sets the bearings out on a map and the point at which the lines intersect fixes the position of the aircraft at the time its signals were received by the three stations. The observation is passed on to the machine. Direction-finding •stations such as these are of great value to the aircraft, because their positions can be traced continuously during the flight so that in the event of any trouble the point at which they were forced down can be determined with reasonable accuracy, and so effective steps can be taken to render assistance quickly. However. in order that the service shall be of maximum value the directionfinding equipment must be of such a nature that it is equally useful not only in daylight, but at night time and at twilight and daybrak. Special equipment is, therefore, necessary land what is known as the Murconi- | Adcock direction-finder performs the I necessary operation with the required I degree of accuracy. This apparatus i requires a. special kind of aerial which ignores everything but the dijrect ray. Tn addition to directionfinding gear, it isfcalso necessary to have transmitters- which can com-

municate reliably.either in code or by telephony with other aerodrome stations, and with the aeroplanes, that are in flight, so that the result of the direction-finding observations can be given to the aeroplane with as little delay as possible. Complete equipment of this sort is, perhaps, the most useful of all, as it enabes the position of the ’planes to be always known at headquarters. It also tells the pilots all they want to know, but it is somewhat confined in its application, because the distances between observation points must be comparable with the length of the flight. In long range flights the power of the aroplan.o transmitter is not always •sufficient to enable bearings to be taken accurately so that the procedure can often be conveniently reversed, and the aeroplane itself carry direction-finding equipment which will observe the direction of powerful ground transmitters. To meet these conditions, various types of equipment, including what are known as homing devices, have been developed. These instruments give visual or aural indications when the ’plane is on or off a course set for a specified transmitter, which usually sends out distinctive signals in a more or less confined beam, although any station, even as a broadcast transmitter can be used. The trouble is that many of these devices are liable to error at long distances or at night time, but with suitable choice of equipment good results can be obtained. All long distance commercial services are provided with some kind of wireless navigating and communication systems, and such facilities are being extended for the England-Australia service. Complete equipment of the kind outlined will ultimately be necessary for all services, including those to Tasmania and those between States, if such uncertainties as those that occurred when the Southern Cloud, and, more recently, the Miss Hobart, were lost. Wireless beacons and' co-operating devices on the ’planes themselves can be very useful. but well equipped and suitably situated ground direction-finding stations seem to be essential for the complete and proper supervision of aerial services which have to cross the sea, or sparsely populated or dangerous country.

BRITAIN’S BIGGEST STUDIO. The largest broadcasting studio in Great Britain, which has recently been opened by the 13.13. C. at Maida Vale, London, has a floor area of lit) feet by 72 feet and a volume of 220,000 cubic feet. The premises were originally a roller skating rink and the new studio has been built inside the original structure. A special control room has been installed with the necessary equipment and permanent, line connections with Broadcasting House. The studio is adequately served with listening rooms, control cubicles, artists’ waiting rooms, etc. The building also contains additional accommodation for recording apparatus. Tt is possible that eventually the remaining space in the building will be used for further studios made necessary by

the expansion in the Home and Empire Programme Services. There are now a total of twenty studios available for the transmissions of every type of programme in London.

SIMPLEST VOLUME. CONTROL. Somewhat out-of-date sets, without any form of volume control and without variable-mu valves, may be fitted with a form of regulation, which can be added without any difficulty and used temporarily until a more up-to-date set is assembled. Some type of predetection control is desirable, and a simple plan is to connect a variable, resistance of some 5000 ohms across the aerial and earth circuit of the set. The variable resister should preferably be of the tapered type, but this is not very important if a plain variable resistance should happen to be available. A volume control of this type is by no means perfect, but it will serve well enough as a temporary measure ROUGH CONDENSER TEST. Although it is none too easy to make a definite test of the condition of a fixed condenser, there are an almost innumerable number of ways of making a rough check. Many methods have been described from time to time in these pages, and now a. reader points out still another which he has found to be effective. The condenser under test is connected momentarily across the loudspeaker terminals; with a little experience,j the resulting alteration in tone and volume will convey a good indication ?.s to the capacity; with regard to insulation, it. will at least he proved that there is not a complete shortcircuit. A large condenser will attenuate the high notes and also reduce the average level to a greater extent than a small one. This test is j only applicable to capacities greater | than, say 0.001 mfd.: even with that J value the alteration in tone may be barely perceptible. RADIO IN PALESTINE. The day when lonely wandering Bedouins in Palestine will have radio receiving sets in their camel packs or donkey saddles is brought nearer with the decision of the Government to equip and operate a broadcasting station under the direction of the Department of Posts and Telegraphs, states the Jerusalem correspondent of the “Christian Science Monitor." A contract for a station to he situated near Jerusalem has been awarded to the Marconi Wireless Telegraph Company. The studios and control room will be in Jerusalem, and will be connect ed by land lines with the transmitter. A special receiver has also been ordered for receiving, and relaying foreign programmes. It is intended that the selection of programmes, which will be transmitted in three official languages— English, Hebrew, and Arabic —will be in the hands of a programme board. The design of the station has been carried out by the chief engineer of the Department, of Posts and Telegraphs, which Department will be responsible for its operations. The establishment of a Government-

controlled transmitting station was first urged by Mr C. F. Strickland, of the Colonial Office, who was sent to Palestine to investigate the possibilities of organising co-operative societies among the Arabs. •

Broadcasting, it is hoped, will prove the best means of access to illiterates, who now get their news by word of mouth. It is also expected to supplement the work of the various Government Departments in the bet-

terment of education, and agricultural methods. It is also expected to be a valuable asset to the Government in settling differences which periodically arise between the Jews and Arabs.