WIRELESS NOTES

New Zealand Times, Volume LI, Issue 11855, 14 June 1924, Page 9

WIRELESS NOTES

By RADIO. - Jfe.

4Y.A. DUNEDIN Those -who tuned *n on Tuesday nighl in the expectation of hearing- Mr O’Neill’* transmission from his new 500 watt plant at 4 Y.A., Dunedin, were seriously disappointed, because, for some unaccountable reason, the music and speech failed to come through. Mr O’Neill has only just installed the now apparatus, which develops 10)J watte, 500 of which is expected to bo transmitted from the aerial, this being by .far the most powerful tion in New Zealand. DESCRIPTION OF SET Mr O’Neill is usiDg six 250 watt valves, three modulators, and three oscillators i of 250 watts each. The pauel consists 7 of two sheets of Junoite, each 3ft square, which are mounted on angle iron brackets turned in at the 'bottom on to a sliolf “ft by 3ft. A boiled stay comes up from this to the top of the ancle iron, and a shelf fitted in halfway. Tho bottom shelf holds "C"' batteries, Choke coils, eto. The centre shelf holds the other gear necessary, and on the top panel will 'bo a pilot lamp on a bracket to light the set, three modulating valves and three oscillating valves, each to take 250 watts. These valves will give an ) efficient 500 watts into the aerial. This, - however, will depend on the class of valve lu.cd. The radiation meter will also be mounted) on this panel. The bottom* panel will cany the Fillament voL and amp. meters, the Milliamp meter, 4 he plate current meter, and six five to 10 amp. stats, will be mounted at tho back of the panel, the shafts projecting through, and dials mounted theroon. unregistered sets t requo.nt warnings have been issued by the department to wireless amateurs against the use of unregistered sets and . prohibited circuits, but in spite of this the practice is still persisted in, and those guilty cannot complain if they are visited with official wrath. The regulations are quite clear on the point, and set forth in the amendments to the Post and Telegraph Act, 1906, that every person who uses wireless sets, for transmission or reception without having complied with rhe department's regulations and secured a license, is liable to a fine not exceeding <£soo. The apparatus may, also be confiscated, and held at the pleasure of the department. The department is very patient and has so far lefrainod from taking action locally, though in other centres offenders hav© been dealt with in tho courts and fined. Those amateurs in Wellington who seem disposed to regard the regulations as more or less of a joke would do well to take warning. RADIO CONCERT The programme broadcasted from the Dominion Radio Compony'3 station on Sunday night comprised the following items:—"l Stood on the River of Jordan" and "Lethe" (songs, with violin and 'cello obligato) by Mr N. A. Bryne; Valeo Triste" and "Reverie" (violin solos) by Miss M. Joyce; "My Gentle Child" and "Arboo at her Lattice" (songs by Miss Jean Joyce; "Oh, Rest in the Lord" and "Caro mio Ben" (songs) by Mrs Rich worth; "Comfort To" and "The Sower" (songs) by Mr E. K. Rishworth; "Ave Veruin" and "Memory Fever" md "Out from the North" (songs) by Mr P. Martin-Smitih; "Polish Dance" and "Three-fours" (violin, piano, and cello trio) by Misses M> Joyce, E. Joyce, end M. P. Byrne; r Sweet and Low’-’ I (vocal trio) by' Miss Joan Joyce. Messrs t D. K. Rishworth and. P. Martin-Smith, with violin obligato by Miss M. Joyce. LONG DISTANCE SETS The last stage in connection with the long distance radio teats between Australia and New Zealand and South Africa was carried out during the present week, but up to the time of writing no reports had come to hand 'indicating the success or otherwise of the experiments, which close to-day. An interesting feature of the tests is that they were conducted at 5.50 a.m. New Zealand mean time 4 a.mm Eastern Australia, and 2 a.m.’ in Eerth. In the east, comparatively little .work has been done in this line during i the earlier hours of the morning, though the general belief is that conditions are very favourable at this time for long distance work. , FACTORS OP EFFICIENCY This is something for owners of wireless receiving sets to ponder over The radio editor of the New York "Tribune" was recently asked: "How would you apportion the various factors affiliated with the obtaining of satisfactory results with ?,„ radl °. re <* lv er?" The editor replied: Uperator, 40 per cent.; aerial and earth, 20 per cent.; ing connections, 10 per cent • locnhonof wiring, « per cent.; wiring and soldering connections, 10 per cent • location of parts, 5 per cent.” The con?w°„ n *? V drawn from the above is ' that nearly half the efficiency of a receivi?B set ,1 s . dependent upon skilful operation. The moral is, “learn to operate your set properly." TENSION BATTERIES ELIMINATED ! „ sp ? clal Mldegram from London to : the Sydney Sun states that "listening- > with valve-sets without the bugbear 1 of high tension batteries, has been ac- 1 complislied by two radio experimenters . mean™ ? OWC ) IDS and Rogere, who, by i means of a step-up transformer, are able 1 . u . se . the small current emitted from a 1 i^nn ed im lom f nt : fi] 111 its resistance. This ' ates the P disto n rtion sC and ry ’"llzling C ” i “in' l SSSSL; f Tr lector and amplifier sets to the simplicity {

of a crystal apparatus, and overcomes the it greatest defect in communication between ’h aeroplanes. It also eliminates the airit driven, high-tension generators, which s- were constantly failing. Mr Rogers was t- formerly with the Marconi Company's id research staff. £ ENGLISH TRANSMISSION 5" The English and Continental concert ** broadcasting stations do not get across to America with anything like the efficiency of the Americans’ transmission, which is regularly heard by hundreds in Groat Britain and on the Continent. As an example, the Eitfel Tower broadcast stas tion, in Paris, S.F.R., using 2000 watts, twice the power of the American stations, was heard for the first, time in. a regular •s concert on March 29th in the United 1' States. The music was picked up by Mr 1 Bert Mkmlto.il, at Chatham, Massachusetts. * It is significant that Eiffel Tower operates on a wave-length of 1780 inetres, as j compared with the/Yankee stations' waves s length of under 550 metres. The dis- ? tance between Paris and Mr Moulton's t home in Massachusetts is less than 3500 5 miles. The Californian music from » KGO which is heard regularly by scores i of New Zealanders, many employing only » one valve, KGO being distanced over 6000 * miles, uses half the power of Eiffel Tower 1 and works on a wave length of 312 metres. ? CARE OF CRYSTALS c . . 1 In receiving sets employing crystal > detectors, the effective range depends a - great deal upon the “sensitivity of the crystal. Some crystals are naturally .more sensitive than others, but even ; a sensitive crystal may be ruined by f jnnpvoper care. Tho action of the air on . .these crystals sometimes oxidises their , surface and prevents them from func- , I' 10111 *!# properly, but a more serious (trouble is caused by touching the surfoce of the crystal with the fingers. , j*nere this has been done and tho surface of the crystal is-found to be less : sensitive after continued use, it should [ be scraped lightly with a penknife. | EDUCATIONAL BROADCASTING . Tlio first test organised on an extensive scale of the possibilities of broadcasting i as an educational medium for use in the schools uas made recently by the British Broadcating Company, in conjunction ; with the London County Council. In over 70 schools, mostly elementary, but including some private schools, loud speakers were installed in the afternoon, and a lecture on school music, given by Sir Henry Walford Da \ies at the Savoy Hill studio of the 8.8. C., was broadcast to more than 10,0 CO children. At some of tho schools L.C.C. inspectors .attended to observe the effect in the class rooms. The lecturer had in the studio 25 L.C.C. school children, who provided a visible audience, and was assisted in the musical illustration of the lecture by six boys of the Temple choir. The illustrations were chiefly drawn from Shakespeare’s songs, and included "Where the Bee Sucks" and "It was a Lover and his Lass." Blake’l anthem "Jerusalem" was also sung to Sir Hubert Parry's setting. Sir Walford Davies explained how simple it was to take certain notes, if , one knew tho proper method, and form them into definite melodies; and in a practical illustration enlisted the aid of some the school children in his audience, as well as the choir boys. Later reports came in from tho schools as to the quality and clearness of tho reception, gnd these showed that the un- t seen audiences of the lecturer had heard I well and had manifested considerable in- ' forest in the lecture and ; the musical illustrations. One fact appeared, and that was that boys' voices wore in dined to sound a little shrill in tho loud speaken?. Mr 0- P. Trevelyan, president of the . Board of Education, expressed 'himself as j greatly impressed by the possibilities of this method of simultaneous lecturing, TUNING FOR LONG DISTANCE A beginner in experimenting wrote to a friend well-known for hie prowess in miedytog long-distance signaiU, asking . m how he managed to bring them lu ;, reply was as follows: Next time you try to tuno in at- dis- 1 ( tant station, make up your mind to take ; every care, and do not move the dials . more thai a thousandth of an inch at ■ Hme. First of all set your valve oscillating-, not too strongly, just past the point where you hear a kind of thud in the receivers, caused by increase in ! i c V' rr ® when the valve breaks into j oscillation. Now tuno carefully until)you hear the carrier wave. It is usually ‘ surrounded by a chorus of squealing' valves, so do not attempt to tune In I one of these by mistake. You-ean tell I 1 the earner wave, because it has a growl J behind it, while the ’how 1 ing* receivers are pure whistle. Now is where extreme ■ care is required. "By very slight adjustments you will find the carrier growing louder and ( louder until you pick up distorted music amongst the whistles, and vou must now i turn down your rheostat, or turn back 1 your regeneration dial, until tho whistle < fades into a low growl, and a very slight t movement will suddenly bring in the i music clearly. You will find this re- 1 quires a good deal of practice to tune < successfully, the carrier wave having a nasty habit of breaking in just as yots have got the music comfortably loud. < The music should he much weaker than < the carrier wave, usually about half I strength or less, and therefore, unless « you receive the carrier wave loud enough * to hear very comfortably, vou will not 1 have much chance of tuning'.in the music and may as well go to bed, or add an- „ other valve, as the fancy strikes you,”