RADIO

Taranaki Daily News, 25 July 1930, Page 12

RADIO

RECEPTION CONDITIONS IDEAL. HOWLERS AND POACHERS.

(By

“B.C.L.”)

Reception conditions have been ideal lately and D.X. reception has been at its best. In the early evening several United States stations have been booming in at great strength, notably K.T.M. and K.N.X., which have been heard at volume equal to that of 4YA. The minor Australian stations are all easily picked up at practically any time of the evening. The writer tuned in on 3LO recently in time to hear the ceremony of lights being switched on from Canada, New Zealand and Cuba by wireless, the. playing of suitable music by the band accompanying the successful accomplishment of the experiments. A correspondent in Inglewood writes bitterly of a vicious and persistent howler who is making night hideous in Inglewood and spoiling radio enjoyment to every other set owner in the town. The correspondent enquires if anything can be done and if there is any penalty for creating a nuisance such as he describes. According to law anyone who allows his set to howl is liable to a fine of £lO and in extreme cases confiscation of his set as well. Unfortunately the North Taranaki Radio Society has no power to deal with such cases as the correspondent suggests. All it can do is to assist the owner of the set if he is willing to be advised, or failing this to bring the matter before the proper authorities. If the culprit knows he is howling he should communicate with someone who cun instruct him in making the necessary adjustments to his set, and so preserve the peace in Inglewood.

During the next, few weeks there are to be some very attractive items broadcast from 2YB, The following are a few of tho special attractions to be heard shortly: Irving’s orchestra (Hawera), a party from the New Plymouth Savage Club, 2YB trio in several new numbers, and several new artists are to make their appearance. The Post and Telegraph Department has declared war on pirates in Wellington and other centres and some very substantial fines have been inflicted. It is rumoured that New Plymouth is to. receive similar attention shortly. There are far too many, of these poachers who are. willing to let others pay for their amusement. An amazing feature is that some of these people have the effrontry to criticise the programmes. An “old-time” programme of gramophone music will be given from 2YB on Saturday night next. SENSITIVITY AND SELECTIVITY.

Judging by remarks heard at the recent radio exhibition at the town hall, Wellington, tho average purchaser of a set and even some salesmen have somewhat conflicting ideas on the subject of sensitivity. Many people confused it with selectivity. In many respects the two terms are completely opposite to each other. One need not have selectivity in a sensitive set, nor need one have sensitivity in a selective set. The more sensitive a set, indeed, the more selectivity suffers, unless special care is taken. A selective set is capable of cutting out stations close together. A sensitive set is capable of picking up distant stations. By the fact of its very sensitiveness stations close together on the wavelength scale will be amplified more strongly than on a less sensitive set. If it were possible to design a one-valve set with an amplification of a thousand it would appear to be far less selective than a set using the same coils fitted with a valve capable of giving an amplification of only ten. Fortunately in multi-valve sets a factor kindly comes to the rescue of designers and automatically increases selectivity with sensitivity. The more the number of tuned circuits in a set the more selective it becomes. ‘ In a one-valve set there is only one tuned circuit —the aerial coil. If a high frequency valve is added another tuned circuit is also added, and so on. The aggregate of these tuned circuits gives to the set an increased selectivity thaj; more or less counterbalances the sensitivity. For certain technical reasons it is not possible to make full use of the sensitivity of a screen-grid valve and at the same time insure a set as selective as Cae older type vf neutralised set. Generally speaking, screen-grid valve sets are for this reason slightly less selective than the older type. In order to rectify this special types of band pass-filters have been designed.. These filters are carefully screened and are coupled to one another by calculable and controllable amounts. ' ?

The general idea is that without adding extra valves a resonance curve is obtained with steep sides and a fairly ilat top. This means that for a certain definite waveband generally about 10— five or six kilocycles the set is peculiarly unselective. Beyond that waveband, which, of course, is created by tuning to a particular wavelength, unwanted signals fall away sharply to almost nothing. This is a most desirable state of affairs. For the musical frequencies, as represented in most carrier waves, if they are to bo correctly reproduced, cover a six or seven kilocycle band. We have made our set therefore amplify the useful part of the carrier modulations evenly without spoiling selectivity so far as other stations are concerned. There can be little doubt that more will be heard of wave-band filters as the ether becomes more and more, crowded.*j..

CAUSES OF STATIC. Listeners will be glad to know that there is every prospect of the coming summer being much freer from heayy thunderstorms than the past few summers have been. These electrical disturbances are to a certain extent connected with disturbances on the sun which reveal themselves in the telescope either as sunspots or immense clouds of luminous gas (writes J. H. El'gie in Popular Wireless). Tho sunspots are known to be vast whirling masses of electrified matter, and it is therefore easy to understand how, by discharging streams of electrons to-

ward the earth, they frequently affect our atmosphere to such an extent as to bring about more- or less violent electrical storms. There are regular recurring periods of about every eleven years when the- sunspots reach their maximum both as regards size and number. One of these maximum periods has just passed; the fact of the sun has become very much freer from large spots, and even the smaller ones are noticeably fewer in number. Generally speaking, there is little doubt that during periods of maximum sundisturbance the listener-in experiences a great deal more trouble with ‘'atmospherics” than when the sun is quieter. “Atmospherics” can ba caused by thunderstorms hundreds of miles from the user of the affected wireless set. While a very conspicuous sun-spot, many times the size of the earth, may pass without- any effect whatever on the atmosphere, an insignificant one is capable of causing no end of trouble to the listener-in, who naturally wonders whence tho irritating interference comes. There was an instance of this curious anomaly (so far as concerned magnetic storms) a year or two ago, when a spot appeared which, so to speak, I scarcely looked at twice with my telescope, but which caused a violent magnetic storm, while a large' spot not long before had failed to affect the earth’s magnetism’ in the least. It will be a relief, to the listener-in, therefore, to know that even these small but potentially troublesome sunspots are gradually becoming fewer and fewer as the thunderstorm season approaches. NEW ITALIAN STATION. OUTPUT VOLUME OF 200 KW. Italy became a. leading factor in European broadcasting at the beginning of the year, when one of the most powerful stations in the world was inaugurated-. The transmitting plant of the radio station is located in Santa Polomba, a little suburb outside Rome, and connected by direct wire to the studios in the heart of the Italian capital. The new superradio station was designed by, and installed under the supervision of, American engineers as part of a contract under which the R.C.A. Victor Company sold the entire operating equipment to the Ente Italiano Audizioni Radiofoniche, the Italian broadcasting company. Programmes of entertainment and news bulletins are broadcast and it is expected that soon the voice of Mussolini will be heard frequently from this station. i The new station represents the last word in broadcast transmitter development and embodies several outstanding advances in American radio technique. While the new station is rated at 50 kilowatts in the antenna, by .means of a special modulation scheme it is capable of reaching a peak'of 2'oo kilowatts output during transmission. In addition, new high-voltage mercury vapour rectifying tubes increase the operating efficiency and affect a saving in energy of from •35 to 40 kilowatts over the ordinary type of valve rectifier. Anothc" feature is the system of constant frequency regulation which keeps transmission steady on the desired wavelength. This -is carried out with crystals which are kept in a special temperaturecontrolled oven. The temperature in this , oven never varies more than one-tenth of a degree. The equipment for tho new station was shipped last August, and construction was begun immediately. La Scala Opera House, Milan, has been wired

with microphones and it is was planned to make broadcasts from this theatre a regular feature. All Italy is most enthusiastic over the quality and power of the station. The 100 kw. valves have | proved fully able to stand the enormous power during the modulation peaks and listeners more than 1000 miles from Rome report clear, powerful and constant reception. TELEVISION BROADCAST. TRANSMISSION OF PICTURES. AUSTRALIAN COMPANY FORMED. The Postmaster-General has given permission for experiments to be made in Australia in the broadcasting of pictures by what is commonly known as the television system. For some months there have been such broadcasts by the British Broadcasting Corporation ,and by different companies in America, all of which are experimenting with a view to perfecting the system of transmitting and'receiving both still and motion pictures over the air. There has been a reasonable success in the transmission of photographs of persons and still subjects not requiring too much detail, but the success in motion pictures has not been great. Both system of transmission are still very much in the experimental stage. A company has been formed in Melbourne under the title of Television and Radio Laboratories Limited for the production of a receiving apparatus which could be used for the reception of weather maps, pictures, duplicates of printed reports on. markets, and other matters of special interest to those residing some distance from the capital cities. The first experiment will naturally be made with the transmission and reception of photographs of persons and still objects as was done in Britain and the United States. It is claimed tliat it will be possible to sell the receiving apparatus from about £l4. The first broadcasts are to be from 2UE in Sydney- and from 3UZ and 3DB in Melbourne. It is expected that the promoters will be able shortly to announce the date on which the transmission of pictures will be commenced. The future development of this system in Australia will be watched with interest by all listeners. Radio engineers believe that the time will come when it will be feasible, from the commercial standpoint, to transmit for the information and amusement of listeners pictures of current events, as is now 'done in the picture theatres, over the air by means of radio —but that time is not just yet.

TO-NIGHT’S PROGRAMMES NEW ZEALAND STATIONS. IYA, Auckland—3 p.m., afternoon session—selected studio items, including literary selection; 5, children’s session; 6, dinner session—“ Columbia” hour; 7, news and market reports; 7.40, talk, J. Montague, “Maori Pronunciation and Place Names”; 8, chimes; orchestral; 8.9, mezzo-soprano, Audrio Golder, ‘I Love Thee”; 8.13, orchestral, selections from ‘Salome”; 8.23, lecture-recital, Mrs. D. Basham, assisted by Lola Solomon, soprano, “Strauss”; 8.38, orchestral, “Serenade,” “Scarf Dance”; 8.47, piano, I. Paderewski, “Valse Caprice”; 8.51, bassbaritone, F. Sutherland, “Cargoes”; 8.56, musical quartet, ‘Quartet in D Minor — Seherzo”; 9, weather forecast; 9.2, ’cello, “Harlequinade”;. 9.6, mezzo-soprano, Audrie Golder, “I Attempt from Love’s Sicluiess,” “Cupid”;. 9.13, lecture-recital, Mrs. Basham, assisted by Lola Solomon, “Chaminade”; 9.28, orchestral, “Callirhpe Suite”; 9.38, organ, “Romanza”; 9.42, bass-baritone, F. Sutherland, “Like to a Damask Rose,” “The Minstrel”; 9.49., string quartet, “Quartet in D Major —Andante”; 9.53, selection, “Der Busenkavalier.” 2xA, Wellington.—3 p.m., chimes; studio items; 3.30 and 4.30, sports results; 5, children’s session; 6, dinner music; selection, Columbia Symphony Orchestra; violin, Toscha Seidel; 6.30, orchestral, Orchestra Symphonique do Paris; band, Band Garde Republicaine de France; 7, news session, market reports and sports results; lecturette, Miss M. S. Christmas; 8, chimes; (Note: During the course of this programme an excerpt from, a sound film feature will be relayed from the Majestic Theatre);

overture, 2YA Orchestrina; soprano, Miss Veronica McKenzie; piano, Miss Eileen Bradley; bass, Mr. W. Binet Brown; selection, 2YA Orchestrina; elocution, Miss Dorothy, Miller; selection, Band of H.M. Grenadier Guards; tenor, Mr. Chas. Williams; baritone, Mr. Will Goudie; selec-

tion, 2YA Orchestrina; weather forecost and, announcements; twenty minutes of vocal gems from Friml’s musical comedy “Katinka” by the Lyric Quartet, assisted by Miss Veronica McKenzie; selection, 2YA Orchestrina; humour, Miss Dorothy Miller; chorus and orchestra, Columbia Light Opera Company; God Save the King. 3YA, Christchurch. —3 p.m., afternoon session gramophone recital; 4.25, sports results; 5, children’s hour;.6, dinner ses-. sion, “11.M.V.” hour; orchestral, Vienna Philharmonic Orchestra; light orchestra, New Mayfair Orchestra; 6.30, orchestral. New Mayfair Orchestra; ’cello, Cedric Sharpe; oi’gan, Herbert Dawson; band, H.M. Coldstream Guards; trip, De Groot (violin), A. Gibilaro (piano), J. Pacey (’cello) ; organ, Herbert Dawson; orchestral, Berlin State Opera Orchestra; 7, news session; talk, Mr. D. Cosgrove, 2nd seri-is of “Radio Service” talks; 8, chimes; overture, San Francisco Symphony Orchestra; mixed quartet, Valencia Quartet; soprano, Miss Lucy Full wood; clarionet solo, Mr. M. E. Withers; tenor, Mr. T. G. Rogers; instrumental, Studio Instrumental Octet (Conductor Mr. Harold Beck); contralto, Miss Mary Taylor; 8.33, popular song, Mr. Clieslyn O’Connor; instrumental. Studio Instrumental Octet; bass, Mr. E. J. Johnson; mixed quartet, Valencia Quartet; clarionet solo, Mr. E. Withers; soprano, Miss Lucy Fullwood; instrumental, Studio Instrumental Octet; 9.2, weather report and station notices; tenor, Mr. T. G. Rogers; popular songs, Mr. Cheslyn O’Connor; instrumental, Studio Instrumental Octet; bass, Mr. E. J. Johnson; soprano and contralto duet, Valetta Duo; instrumental, Studio Instrumental Octet; 9.30, dance music until 11 p.m.—“11.M.V.”; 11, God Save the King. 4YA, Dunedin.—3 p.m. chimes. Selected gramophone items; 4.25, sporting results; 5, children’s session; 6, dinner music, “H.M.y.” hour; suite, New Light Symphony orchestra; Philadelphia Symphony Orchestra; waltz, International Concert Orchestra; march, Philadelphia Symphony Orchestra; 7, news session; 8, chimes; orchestral, 8.8. C. Wireless Symphony Orchestra; soprano, Miss Muriel Eagar; instrumental, 4YA Trio; recital, Miss Leonore Mackenzie; 8.31? tenor, Mr. J. E. Davies; piano, Friedman; contralto. Mrs. Nellie G‘, Shrimpton; in-

strumental, 4YA Trio; bass, Edward Bond; 9, weather report; orchestral, Menorah Symphony Orchestra; soprano. Miss Muriel Eagar; duet, Max Scherek and J. A. Wallace; chorus, Don Cossack’a Choir j recital, Miss. Leonore Mackenzie; 9.30, tenor, Mr. J. E. Davies; instrumental, 4YA Trio; contralto, Mrs. Nellie G. Shrimpton; ’cello, Mr. P. J. Palmer; bass, Mr. Edward Bond; orchestral,.New Queen's Hall Orchestra; 10.3, God Save the King.