TO-DAY’S WIRELESS PROGRAMME

Manawatu Times, Volume LV, Issue 7295, 4 August 1930, Page 5

TO-DAY’S WIRELESS PROGRAMME

2YA WELLINGTON, . (720 Kilocycles). THE SECOND DAY OF “MUSIC WEEK.” ' 12.30, from the Town Hall, relay of the Special “Music Week,” organ recitals* and community singing; 3.0, relay of the Combined Schools Concert from the Town Halljj 5.0, children’s session; 6.0, dinner music; 7.0, news session, market reports and:sports Results; 7.40, lecturette, Mr. H. O. South, 'Books—Grave and Gay’; .8.0, relay of the Wellington Symphony Orchestra’s Special ‘Music Week,’ concert from the Town Hall. 3YA CHRISTCHURCH, (980 Kilocycles). 3.0, gramophone recital; 4.25, sports results; 5.0, children’s hour; 6.0, dinner session; 7.0, news session; 7.30, talk, Mr. E. E. Wiltshire, President of Linwood Library, ‘Books of the Month’; 8.0, band programme by Derry’s Militay Band, assisted by 3YA artists; 8.11, male quartet, ‘On the Banks of the Wabash, Far Away’; 8.15, instrumental, (a) ‘Serenata’; (b) ‘Serenade’; 8.27, soprano, Miss Gladys Brooks (a), ‘Tho Sally Gardens’; (b) ‘Cuckoo’; 8.27, band. Humoresque on ‘The Merry Widow Waltz;’ The most popular melody in the opera is burlesqued in the following manner: Introduction and Theme. I—A Little German Band; 2 A Flute Solo with Organ Effects; 3 The Amateur Trombonist; 4—A Street Piano; 5 —A La Rag Banjo; 6 —Finale —A Brain Storm; 8.33, humour, George Graves and Myles Clifton, ‘ The *ole in the Road’; 8.41, instrumental, ‘Rondo’; 8.51, baritone, Mr. Sydney

W. Armstrong, (a) ‘Friendships’; (b) ‘Yours and Mine’; 8.57, Romanza — band, ‘Alla Stella Confident©’; 9.5, orchrestral, ‘The Dance of the Dwarfs’; 9.9, soprano, Miss Gladys Brooks, ‘Where the Bee Sucks’; 9.13, organ, Frederic Curzon, ‘For Old Time’s Sako’; 9.16, waltz, band, ‘Jolly Fellows’; 9.23, male quartet, ‘The Sidewalks of New York’; 9.27, instrumental, (a) ‘Canzonetta’; (b) ‘Gavotte’; 9.35, humour, Flotsam and Jetsam, ‘The Business Man’s Love Song’; 9.39, selection, band, ‘Reminiscences of All Nations’; 9.50, baritone, Mr. Sydney W. Armstrong, ‘Hail Caledonia’; 9.54, organ, Emil Velazo, ‘La Golondrina’; 9.58, march, band, ‘Emperor William.’

4YA DUNEDIN, (650 Kilocycles). 3.0, gramophone items; ,4.25, sporting results; 5.0, children’s hour; 6.0, dinner music; 7.0, news session; 7.40, talk, under auspices of W.E.A.; 8.0, chimes. Special programme of operatic excerpts and incidental music by the Dunedin Orphans Club, Conductor of Orchestra: Mr. E. Kerr. Programme Organiser: Mr. E. Bryant. Honorary Pianist: Mr. Thos. J. Kirk-Burnnand. 2ZR WANGANUI. (600 Kilocycles). This station is on tho air every day from 10.3 oa.m. to 3 p.m., and in the evenings from 7.30 o’clock. 2FC SYDNEY. Tho Evening Presentation—S to 11.30 p.m.: A typical holiday night programme. Band music and commvfiity singing from tho Ashlield Town Hall, arranged by the Asbfield District Band. With Charles Lawrence as director. Assisting artists: Douglas-Graham, comedian, and Vera Passmore, contralto. 2BL SYDNEY. To-night’s Presentation —8 to 10.30 p.m.—Dr. Harvey Sutton will commence the series of August Lectures, under the auspices of the University Extension Board. His general subject is ‘From Baby to Athlete—Food and .Muscle.’’ To-night ho will deal with ‘Growth and Food Requirements.’ The Light Orchestra are playing popular selections, and then we cross to the Sydney • Stadium for a description of tlic Wrestling Contest.A GOOD JOKE. There is a good story going the rounds among the Radio fans of Palmerston North. A local listener who owns a 3-valvc receiver which naturally tunes very broad, decided to build a wave trap in tho hope of cutting out the local station. After working on tho apparatus all Sunday afternoon and evening, the device was ready for a trial. At 8.10 p.m. it was duly connected up and the dial turned when 2ZF was cut out completely and 2YA tuned in for the rest of the evening. Tho listener joyfully showed his admiring wife what a great devico it was and also next day told all tho radio fans at . the office, but failed to understand why everyone did a grin and did not seem at all enthused about such an efficient wave-trap. - The following Wednesday, the listener in ouestion, tuned in to, 2ZF and heard them apologising for the breakdown which put them off the air at 8.15 p.m. the previous Sunday. _ Then

it dawned on him why his wave-trap had beeu so efficient, and why the radio fans at the office had ali grinned at its wonderful efficiency! KEEP THE AERIAL CLEAN. When 2ZF went off tho air suddenly oil a recent, Sunday night, many listeners waited patiently in the hope that the trouble was only of a few minutes duration. The Club had an old valve which had been tested and found previously to work in plaeo of the oscillator valve which had burnt out. In fact, a test had been mado only eight hours earlier which had proved its efficiency (but at reduced volume) by a report from a listener in Wanganui. But although everything was dono to get on the air again, the aerial meter refused to move, although tho meters in the plate, grid and tank circuits showed that the old spare valve was oscillating. Two other valves wero taken out of, their position as modulatarv and tried as oscillators, but to no avail. The oscillating valve generates what is known as tho “carrier wave,” but the “aerial” refused to radiate the power. By this time it was known that something had gone wrong with the aerial circuit and the job would have to be given up for, the night. Early next morning test instruments were used and the aerial showed a low insulation test, so it was dismantled to look for leaks in the insulators. There are two heavily insulated porcelain wall insulators to lead the aerial and earth wires out of the transmitter room and it was found that owing to frost rnd rain these had got moisture in tho centre hole, with the resplt they developed a leak, thus altering the “fundamental wavelength” of the whole aerial system sufficiently to place its natural wave-length outside of the tuning condenser range. The wall and roof insulators were cleaned and reassembled, and while this was being done, the rest of the transmitter was tested and the radio frequency choke coil, a very important device which prevents the carrier wav© from going where it is not wanted and causing “mush” in speech and music, was found to have been burnt out also. A new one was designed and mado locally and installed, and the result of the spring cleaning of the insulators was shown in the aerial meter which gave a higher reading, indicating more power being radiated in the “sky wire” on the test. While transmitting aerials have to bo more heavily insulatod than those of a receiving set, the principle involved is almost identical. Leaky insulators and wall will seriously lower the efficiency of any aerial. A poorly insulated aerial where it is taken through the wall will change its fundamental wave-length in wet weather, and on some sets this alono will seriously alter the range and power of the radio set. Broadcast listeners should periodically lower their aerials and elear the dust and grime from the insulators and make sure that the aerial system is extremely well insulated, if they want to get the best results. The advantage of keeping the aerial insulators clean and keeping the insulation through the wall where tho aerial is taken in, up to a high value is important when chasing a weak station, while it will give increased volume on powerful stations.

RADIO WEDDING MARCH. Oyer a year ago—on July 10, 1929 —when the Karamea district was in the throes of th-3 great earthquake—and still is completely isolated, except for precarious access by way of the sea or along the beach—a marriage was being celebrated and 3YA received a request to broadcast a Wedding, march as radio was the only means by which music suitable for the occasion could be obtained. 3YA did so, and received the thanks of the parties concerned. Now, a, year later, as indicative of the gratitude felt, comes the following appreciative letter:— “I am writing to acknowledge and to thank you sincerely for your kind action in broadcasting a Wedding March on the evening of July 10, 1929, during which time this district wa,s in a state of turmoil owing to the disastrous earthquake of Juno 17, 1929. AVc appreciated your action very greatly ana the reception here was splendid. Once again I thank you most sincerely.” FAULT FINDING IN RADIO It often appears to the owner that a radio receiver is an extremely fragile object, always breaking down and giving trouble. Undoubtedly a radio set is more liable to break down than a motor car or a piano, but this is not duo to the fragility of its construction; but Tathcr to the fact that it consists of a chain of apparatus, and if any links of the chain are defective the whole chain breaks and the receiver is out'of action. If a nut comes loose in a motor car, it may rattle, but it is extremely unlikely that it will stop the car. On the other hand, a similar accident in a radio-set produces Tattles, if not a complete stoppage, and reproduction is ruined. In the motor car each part, with the exception of a few essentials, functions independently, but in the radio set the signal has to pass through every part, and therefore a defect in one is equally as serious as a defect in all. One of the greatest problems in manufacturing radio sets is caused by tho numerous connections necessary Id the internal wiring. There are probably over 100 soldered or screwed connections in even a small set, and if any one of these is not a good connection, trouble is experienced. _ Thus ten bad connections may cause the failure of ten sets, and yet tho percentage of defective work is only 1 per cent. This fact has done much to ago radio engineers beforo ■ their time. Sooner or later a radio set is bound to develop a defect, and knowledge, combined with intelligence, is required to find quickly tho source of the trouble. It is somewhat amazing to watch an experienced service man looking for a fault. Most

probably the only tools bo uses aro bis lingers and a short piece of wire. With these* provided that the user knows how, it. is possible to localise any troublo in a very short space of time. This is because the parts, as previously stated, aro connected in the form of a chain, and tho expert can rapidly test each link of the chain, starting from one end, and so locato tho defective link. It is a more difficult task to find the precise fault after its location has been found, and for this purpose it is often nbccssary to uso a set of testing meters in addition to intelligence ana knowledge. .

A. radio set consists of four main sections—a radio section, a detector section, an audio section and a power supply section. Tho actual process of locating the fault is based upon observations of each section in turn. It is usually best to start at the end of tho receiver, that is, tho power valve, rathei than at the beginning. In inosts sots a slight hum is heard in the speakor, and this hum indicates that tho main units of the power section arc operating. It no hum is heard tho output of the power section can bo checked by momentarily touching a speaker terminal with a wire' whose other end; is connected to earth. Observe tho word “momentarily" and use a piece of insulated wire, as the voltages aro usually high enough to bo unpleasant. If no. spark results from this test it is a sign that tho rectifier valve may be defective, the filter condenser punctured or a transform cr burnt out. If the power supply is 0.k., tho power valve should next. bo tested. The quickest test for this purpose is to touch tho grid connection of the valve with the earthed wire, when a click should be heard from the speaker. If not, the valve may be burnt out or the speaker defective. It is quite simple to find out. which. If satisfied with the operation of the power .valve, the first audio stages can then be checked by touching the grid of the detector or first audio valve with the finger. A click should result from these tests. If not. it may be due to a defective valve or transformer. The latter can be tested quickly by means of an earthed wire by touching the plate terminal of the valve with it. Again, proper functioning is demonstrated by the click from the speaker.

Tlic experimenter is warned to make contact with the wire for only a, fraction of a second. If the detector uses anode bend or power detection, touching the grid of this valve has little effect. It is most convenient to test the radio sections by means of a wire from tho aerial. If this wire is connected to the plate of the last audio valve, signals should be received as proof, of the operation of the detector. It is thus possible to check each, radio valve in turn, and it should be observed that failure to receive signals is an indication that a fault exists in either the tuning circuit or the valve after and not before the valvo to tho plate of which the aerial is connected. The most common faults in the Tadio section are due to a short circuit in tho tuning condenser, a broken coil or a defective valve. Incidentally, as the aorial is moved from plate to plate towards the first, valves of the receiver, reception should increase in volume. Tho foregoing tests, combined with some common sense, will rapidly locate any source of trouble, or at least indicate which valve is not functioning, Great caro should be taken when applying tests to an electric receiver, as the voltages arc dangerous, and the inexperienced are strongly advised to employ the services of an expert, as, although the tests arc simple, the results require interpretation and, if wrongly applied, may cause damage ,to the receiver.