THE COMING WEEK.

New Zealand Herald, Volume LXVIII, Issue 20866, 7 May 1931, Page 15

THE COMING WEEK.

AUCKLAND PROGRAMMES. The following aro features of tho programmes from stations 11A and IZR next weak: — Sunday.—lYA 3 p.m.: relay of Youth Rally from tho Town Hall, speaker Lord Bledisloe; relay of evening sorvico from St. David's Church; studio items. IZR: ( J a.m., childieu's session; 9.45 a.m., Presbyterian studio service; 7.30 p.m., Church of England children's sorvico; 8.30 p.m., Church of England studio service. Monday.—lYA: Silent. IZR:' Talk. to farmers by All'. \V, Alexander. Tuesday.—lYA: Topical talk by Mr. A. B. Chappell, M.A.; numbers by tho Monto Carlo Orchestra. IZR: Morse instruction by Mr. H. !»• Arthur; ijew gramophone record releases. Wednesday.—lYA : Fantasy, " .'Dreams of Long Ago," by tho choir and Orchestral Octet. IZR: Health lecture by Mr. C. S. Bone. Thursday.—lYA; Manufacturers lecture, "Citrus Fruit Products " ; relay of Bohemian Orchestra concert. IZR: Talk on " Sunspots," by Mr. J. H. l'icld; gramophone recital. Friday.—lYA: "Radio Magic, by "Mister Ree"; selections by the Orchestral Octet. IZR: 2.45 p.m., broadcast to Otakiri school, Bay of Plonty; 8 p.m., community singing; 9 p.m., studio programme. i . . , Saturday.—lYA: Relay of Municipal Band concert. IZR: 1 p.m., sports resume; popular programme. VATICAN CITY STATION. NOVEL TECHNICAL DETAILS. VALVE MASTER DRIVE CONTROL. An interesting feature of the Vatican City broadcasting station HVJ is tho aerial lead-in system. For reasons of space the 200 ft. aerial masts had to bo erected outside the Vatican gardens and to tako the lead-in over tho Roman wall, •which is about 50ft. high, to the transmitter building a brick tunnel some 150 ft. long had to be constructed. Tho lead-in consists of two coppor tubes, one inside the other. Two lcads-in aro needed because of the special short-wavo aerial used. There aro actually two aerials on the same support. One is used for tho 19.84 metres wave-length and tho other for the 50.26 metres transmissions. Between the two slender lattice masts is a cable 296 ft. long and the two aerials hang down ' from this. A third aerial, much smaller, is also suspended from the aerial masts 'being used for a receiver in the Vatican. Tappings aro taken from it at carefully measured points and its electrical length and hence its natural wave-length can be varied by means of a switch in tho control room of tho station. As this wire is only a few yards from the transmitting aerial it would be impossible to transmit and receive at the same time. In spite of the fact that the lower of the two wave-lengths, 19.84 rnetrc3, is very short, crystal control is not employed, a special valvo master drive being used instead. This extremely complicated, piece of apparatus is housed behind the second of four panels in tho transmitting room, while fv separate-valve drive bo--bind tho third panel is used for the 50.26 metro side. One of the other panels contains an H.F. amplifier for both wavelengths, while the other carries the modulator equipment and also a special keying device, the transmitter being used for Morse ' when necessary. Only to 10 kw. of unmodulated carrier-wave energy is delivered to tho aerial, the modulation being 80 per cent.

DOMINION BKOADCASTS. analysis of operations. An analysis of the broadcast service in New Zealand for the year ended March 31 shows that the four YA stations were on the air for tho following times: IYA, 313 days, total hours 2395; 2YA, 324 days, total hours 2392; 3YA, 319 days, total hours 2317; 4YA, 321 days, total hours 2263. The aggregate number of hours of broadcasting of all four stations vra. s 9372. Dividing this time into the session classification, Abo times work out: Afternoon sessions, 20.9 per cent.; children's sessions, 12.3 per cent.; dinner music, 11.4 per cent. ; news and instruction, 10.3 per conkj entertainment (main sessions), 33.4 per cent.; church relays, 3.3 per cent.; sporting relays, 6.8 per cent.; overseas broadcasts, .5 per cent. (43 hours) | miscellaneous, LI per cent.:

" HOWLING " IN VALVES. REMEDYING THE TROUBLE. One of the most annoying little troubles which can occur in . radio is the gradually-building-up howl which is caused by a. microphone valve, says Popular Wireless. With many valves it can be -cured by sticking a lump of plasticine on top of the valve or by damping tho glass in some other manner. Sometimes, however, practically any valve put in the detector position will start up a howl, all with their own particular note. This generally only happens when a Yoj.y high degree of magnification i 3 being obtained from the various stages of the set, or when tho set is working right on tho edge of instability. It will also be found as a. rule that in such cases s. rather higher H.T. voltage than usual is in use on the detector valvo, making itmore sensitive than it would be normally.. If euch is tho case the remedy is obviously to redtico tho voltage, when tho trouble is almost sure to ccasc. It may be necessarv to go as low as 30 to 40 volts, but, the loss in sensitivity will not matter in a set, with high-gain L.F. stages.

2YA MORNING SESSIONS. From Monday 2YA, Wellington, will co on tho air dailv, except on Saturdays and Sundays, at 10 a.m., thus extending tho transmission hours by five hours daily. Various talks of an entertaining and instructive nature will bo presented dying the morning sessions, while many other attractions are being arranged.

GIANT POLAND STATION. What is tho most powerful station in Europe and probably in the world has been completed by Marconi s at Basin, near Warsaw, Poland. Tho station operates on 1411 metres and boasts 160 k.w. of power. It has taken over the daytimo programmes of the Warsaw station and will gradually replace that station altogether > Five smaller' stations aro to bo supplied to Poland. Tho Rasin station has the highest, broadcasting masts, with the exception of radio towers, in Europe, namely, 600 ft. The primary is 700 k.w.-, of which eight 100 lM.\ valves deliver 160 k.w. to the aerial. I,ie plant has an 80 per cent, modulation;, with a straight line characteristic throughout a frequency of from 30 to 10,000 cjcles. '