RADIO RECORD

Greymouth Evening Star, 2 June 1938, Page 11

RADIO RECORD

NOTES FOR LISTENERS-IN

(By

“Reception”)

LICENSES IN BRITAIN. NEARLY NINE MILLION. The 8.8. C. estimate's that the number o£ wireless licenses in Great Britain will continue to increase until the total reaches 9,500,000. or 1,000,000 more than at the end of last year. According to the 8.8. C. handbook for 1935, the present total of 8,500,000 is more than 14 times as great as that at the end of 1923 and twice as great as the total six years ago. } In every hundred families of Great Britain and Northern Ireland there are 68.3 wireless licences'. This ratio is exceeded only in the United States, where the latest estimate is 71.5, and in Denmark.

Density of wireless' licences is greatest in the Midlands and West country, where there are 76 per 100 families. London, with 73 per 100 families, is also above the average for the country as a whole. North Region, with 66, is slightly below the average. Scotland and Wales have 59 and 58 licences per 100 families respectively, and Northern Ireland only 37. As the number of families in the country is still on the increase, and many parts lag behind the national average, the 8.8. C. assumes that saturation point has not yet been reached. Figures published in the handbook show that radio is least popular in Fermanagh and Tyrone. Northern Ireland, where the average is 20 per 100 families; Londonderry is little better with 29, and North Scotland reaches only 32. During the year there were 100,000 hours of broadcasting and television, an increase of 13,000 hours on 1936. The number of listening schools rose from 5,000 to 6,890 in England and from 750 to 881 in Scotland.

POLICE RADIO NEW SOUTH WALES SYSTEM. Since the initial installation in 1924 the New South Wales police radio patrol (system has been continuously developed 1 and extended, and now for technical efficiency and practical utility it ranks with the best in the world. Fourteen patrol cats and

i two • launches are fitted with equiplinent. and operate within a radius of j6O miles of the Sydney station and a radius of 40 miles' from Newcastle. (Last year more than 10,000 messages relating to police matters and stolen cars were handled, an increase of 2500 messages over the total for 1936. The main transmitter is at Redfern training depot, a site which is sufficiently free from surroundings likely to absorb the signal. The, unit is energised entirely from the alternating current .mains of the city network,! and is crystal controlled to ensure constancy of wavelength. It is de-j signed either for continuous 1 wave) telegraphy, with a. power output ofj 700 watts, or telephony with an out.-] put of 200 watts, and may be install-] taneously changed from one system | to tho other. ,The aerial is supported ! at a- height of 120 ft between steel masts 80ft apart, and an extensive earthing system is buried below the; lawn of the depot. So that the sta-

tion will never be “off the air,” an) emergency telephone transmitter of] 100 watts output complete with duplicate speech amplifier and emergency] aerial is kept standing by for immediate use. It may be changed from] main to auxiliary aerial in a second. The 100-watt Newcastle station operates on tho same frequency as tho main Sydney station for 20 hours each day. and in its general characteristics .if resembles the Sydney station. In Sydney the receiving station, at which messages from the cars and launches are picked up is installed in a suburb, which is relatively free from electrical interference. The mobile transmitters are of relatively low power, and their signals are consequently not always strong, so that a site free from] electrical interference is essential. ( The receiving point, which is' about seven miles from the main transmitter, is provided with a number of sensitive superheterodyne receivers, any of which may be connected to a, direct j land line to headquarters. To main-i tain a high standard of efficiency, a] special test room and staff are em-| ployed, and with a. complete stock of spare sets and parts, a faulty set or piece of apparatus can be quickly repaired or, replaced at any hour oi the day or night, and. in order to make I doubly sure that, the service is fully effective, lhe wireless personnel is

thoroughly trained, the whole of the radio staff holding first or second class comrpercial licensees. The aim is to develop the service so that not only communication with mobile units) may be guaranteed, but also so that existing telephone and telegraph networks may be supplemented, and to provide a, radio link between station's) where a. radio staff is- located for uso during emergencies.

THE 8.8. C. FAMILY AFFAIRS A CONCERN. | Divorce, marriage and 1 maternity are setting the 8.8. C. several difficult problems, says Garry Allighan. New rules governing these matters' are being drafted by Sir John Reith. I There has always Ijpen a. strict I 8.8. C. regulation that any member of lhe staff who is the “guilty party” in a divorce case must leave the service. Recently five 8.8. C. officials' have been concerned in divorce actions. During the 10 years' of its history the 8.8. C. have dismissed six officials on account of divorce proceedings. Marriage is also giving the 8.8. C. a. puzzle. ‘Ariel,’ the 8.8. C. staff magazine, has some caustic remarks to make on the working of “the' marriage ban.” which, it suggests, is not uniform in operation. “It depends entirely on the status or grading of the woman concerned, so that she has to be pretty high up and formidable in order to retain her job after marriage. The smaller fry disappear automatically.” On the question of maternity feeling runs very high. Female members of the staff have received a memorandum stating that if any of them “contemplate maternity” they must, inform (ho Director of Internal Affairs, who will advise them as to the effect it will have on their staff position. All these domestic, matters could be dealt, with by a staff organisation. It is now proposed that the 8.8. C. authorities' should organise a “house union” which members of the staff must

join. Such “company unionism” will bo fiercely fought by the trade unions. ’RADIO BY TELEPHONE. ■’ ’l’lio development of the telephone system as a means of distributing radio programmes was suggested by Mr T. S. Skillman, assistant chief engineer of the Philips Company, Eindhoven, Holland, when speaking at the World Radio Convention. Sydney. Transmission of radio programmes by ether-borne methods.” said Mr Skillman, was liable to distortion by static, and other causes. It. was also necessary for aerials to be erected by the public. The distribution of programmes; by carrier current through

telephone wires would eliminate dis- ! tortion and facilitate reception. The day would surely come when every home would be connected by telephone and electric power, and) these two connections would provide many services, besides those for which they were originally intended. By means of the*" carrier current system, radio programmes could be distributed through either telephone or electricity system, and other services; to the public, such aS the provision of hot water services on a, community basis, could follow. Radio receiving" sets would still be required, but aerials would be eliminated. LIGHT FROM BROADCASTING. Free lighting, such as that obtained in Hamburg by market gardeners in the vicinity of the broadcasting station is not likely to affect, the revenues of electricity supply authorities. Under the best possible conditions, very close proximity to a powerful station and an elaborate- pick-up system, broadcasting would only supply a few watts of power. A low voltage lamp connected in a circuit tuned 1 to the wavelength of the source of energy is all that i?) required, but tho source of energy must be either very close or very powerful. Even when schemes such as) this are operated, it is doubtful if the length of the station would be seriously affected. The output of a, station, is distributed equally in all directions. The intercepting circuits' would have to be placed side by side sb as to form a high and compact screen before an appreciable lessening of strength would occur. It does not take much energy to operate a senstivo receiver. Engineers of the General Electric Company (U.S.A.) have estimated that within a hundred' miles of thejr 50 kilowatt station at Schnec(ady there would have to be eight hundred billion receivers all working at. the same time to absorb the output of the station. As> every person in the world would have to come along with about 800 sets) each to achieve this result, there is not likely to be any danger of receivers alone cans ing a shortage of signals. Steel frame building, pipe and conduit systems, and uneven country can do fai more damage. PROGRAMMES BY WIRE.

The British Post Office has decided (hat it will establish a public experimental wire broadcasting service> in Southampton this year. Jn> additio to special wire connections experiments will also be made with the existing telephone wires. A choice o - everal programmes' is to be given at a cost of 1/6 a. week, plus an intia payment. Tho whole scheme probably cost £200.009. The wireless industry and its supporters are up in arms, at this development, contending, that expenditure on this scale, is not justified for what it is submitted, is merely a duplication of an existing service and unfair competition with an existing industry. In some quarters it is hinted that the scheme is' connected with national defence. In others this suggestion is looked upon as only a flimsy excuse. NOISE REDUCTION. While tho installation of noise reducing aerial systems, built especially for a certain receiver, is often beneficial, many experimenters install inefficient systems in relatively noisefree areas. In such instances much better reception can usually be secured with an open-type aerial. The set owner can demonstrate to his own satisfaction whether or not he is -ecuring the best reception possible from his aerial. The coupler, if any, •if the receiving end' should be disconnected from the transmission line lead-in and from tho set. It the re eciver is provided with two aerial terminals and one ground terminal, the aerial terminal nearest the earth ter minal should be connected- to the earth, terminal and earth co “"® c made to the earth terminal. Compare the operation with the usual system. Disconnect the earth and make a second te"t A third and final comparison should be made with the ground still disconnected' and the txvo leads in connected to the earth terminal. The foregoing simple tests will otte disclose a much more effective. pick up system in districts where noise is not too pronounced. COMMON WAVELENGTH. First utilised bTLhe British Broadcasting Corporation’s cl ™aral network, systems on which ®eve < widely separated stations bloa < the one programme on an identical wavelength have come into wide fav our. Tn addition to the two majoi American networks, the C.B S. an ibe NB.C. seven European countr have arransed' nineteen ehaina channels thus treeing 06 inoacicasL pther . and casing congestion on the et e Further steps are to bo taken tn tins .Urectlon, and it is hopedb »><»«£ nvovidin" - the Brussels; Control Vabi tro,, whree frequency ia, ?asureinents are constantly being made on long, medium and short waves with new equipment, to hold broadcast ng sta lions accurately to their allotted programme interact ion.