Wireless Broadcast

Star (Christchurch), Issue 17192, 8 November 1923, Page 11

Wireless Broadcast

Contributed by

"Aerial.”

“Hallo, you're just in time to see the whole show go up in smoke, so runic right in.” Thus spoke Mr .1. Or bell, of 3A A. as I knocked at the door of his wireless room on Monday evening. Accepting the, invitation to curne right in,” I edged into the room to find a little knot of interested people, all anxiously watching the works. Among those present was Mr F. D. Bell, better known as 4A A, who was helping Mr Orbell to get things going. For this was THE night, the night when Aussie and Now Zealand ” haniis ” were to start transmitting test signals to America. After a few minutes spent in making some final adjustments, the filament of the big 250-watt Marconi -Os ram transmitting valve was lit and the power turned on. All eyes were glued on the aerial radiation meter, and a great sigh of satisfaction went up as the pointer of the meter moved over. Then power was cut off. and some niofc adjustments made, and another trial was given, but it was not until an hour’s experiment ing was done that the full possible output was obtained from th© set. A little later New Zealand’s highest powered amateur valve transmitter was sending out its first, call to our “ wireless M friends in U.S.A., who at the time were standing by for Australian and New Zealand signals. For the benefit of those who want to know the details, the following notes may be found interesting. The valve itself, about as big as a young football, is rated at 250 watts input, with an anode potential ot 1500 to 2000 volts. A special transformer, whiah is being made for the job, was not quite finished, so power was obtained from two B.F.JT. generators, which were both belt driven from one motor. The generators, which were connected in series, gave n pressure of approximate ly 1200 volts. This, of course, could not work the big “bottle” at full power, but it w r as the beet that could be done, after it was found that the transformer was not ready. The circuit used was the “ Colpitts,” which is the favourite at BAA. This station usually transmits with a power of ten watts, so the only alteration necessary was the addition of a second generator, which was lent for the occasion by Mr Bell. The big vbe was simply connected to the rest of the. circuit in place of the usual two five watt valves. The aerial/ radiation meter also had to be altered to cope with a heavier current, and time did not permit of an accurate calibration of the meter 6inco it was altered. But the approximate calibration showed the big set «o be radiating at least four amjieres. Radiation on ten watts is usually about two amps, so considering that the 260 watts was only being worked on about half power, results were very gratifying. At the time of writing no news hasbeen received from the American listeners, though a message is expected from GKA or 6CGW at any time. During the evening one or two Australians and another Maorilander were heard calling U.S.A. Judging by the noise they made, they stand a good chance of getting over. One Australian amateur, Mr Charles Maelurcan, 2CM, of Sydney. has been hoard before in Hawaii, so things are very promising. The radio publication known as “ Popular Radio ” reproduces a letter received from an Indian guide in the backwoods of Canada, just as it was received at the broadcasting station YY.G.Y. in Sehnectadv, New York : i am gide for hunter man wot com© at dis place Lac-de isles for hunting deer, dose hunter man bring it with Him a mashine for lieer you spik Sunday nito my old modder dats long tiTne i dent see my modder an i tink dats dame fine Song also J hear odcr song i dent no de name, tuesday nite storie for re small boy all girl bout mak de star shine for dem if dey is good buy an girl, hunter man laff like hell an tole mo ax you how we make some moonc-

shine, i hear u spik just de same like your at ine place, i tink you have good mashine i liASen more nex week tank you and much oblige gide Camille Poirier. Ctiemis. P.O. Quebec, Canada. The tedious five-minute-intervals that have marked the concerts transmitted by IYA arc now . 1 believe, a tiling of the past. An Auckland wrier savs the listener-in will get his full period of pro gramme, and will not find it necessary to fill in the intervals combing the air in search ot 2YB or 3AC. Mr White, of 7YA, and his staff will receive hearty thanks from their * unseen audience for the new conditions, which will place Auckland on a par wth the other broadcasting centres of the Dominion. The following discovery was announced in a recent issue of “ Western Electric.” the official publication of the Bell Laboratories “ Wire less fans who have loud speakers arc acquainted with the singing noise, which the oscillator sometimes makes. Some people are discourteous to call it howling, but, of course, when anybody attempts to sing, unless they ran show diplomas from several conservatories of music, they are liable to be misjudged and even maligned—vacuum tubes being no exception to the rule. This singing noise has been the cause of no little research, but the answer was reached the other day by a West Street engineer. In dissecting u. worn-out “B” battery, he found that the‘cells wore wrapped in scrap sheet music. He claims that the electrons get all jazzed up from being surrounded by music, !• i that they just hare to make, a noise. Hence the sing. Next, please. The broadcast station of the tt.S.C.. 3AC, will be working overtime this week. Concerts will be transmitted dll Wednesday evening, Thursday eveiir ing. all day Friday till 0.30 p.m. and again on Saturday and Sunday evenings. At the Show Grounds the Radio Society of Christchurch are giving a demonstration, and those- who are strangers to radio, will have a good opportunity of becoming acquainted with tho wonders of modern wireless telephony. Th© society will not hold it’s usual meeting on Thursday, and the following Thursday is to be devoted to u social evening in the club’s rooms. All information can be obtained from Mr J. W. Webb, care L. M. Tsitt and Co., or from Mr L. Steel, at the showroom of Messrs \N . B. Scott and Co., Gloucester Street. City. Come along and see what a gang of “ hams ” can do. Mr F. J). Bell, AA. of Palmerston South, is in Christchurch for th© holidays. This well-known amateur is the guest of Mr T. Jamieson, of Feudal ton. One of Wellington’s genial hams. Mr R. G. Black, has been staying with liis brother in Lin wood for a few days. He railed on “ Aerial.” and spent an hour or two chatting oil current radio topics. Mr Black returned to Wellington last Tuesday evening. An excellent example of low-power-ed efficiency is shown by ,Mr Slade, of Dunedin. Using a transmitter with an input of two and a half watts, Mr Slade works almost anywhere in New Zealand. Two receiving Y 24 valves with eightv volts on the plates is all that is sused. Mr Slade was heard working 3AF on phone a few evenings ago, and since then he has been heard working several stations in the Wellington district. What next !To China on an " Ora ” with twenty volts on the plate methmks. 3AB is still working feverishly on liis filter, and making good headway, as his generator hum is a little less severe now than it was two months ago. Where did all those Christchurch radiophones spring from? Loop modulation is getting very popular since 3AF started the craze. 3A.F by tho way has worked four hundred miles on his five watt phone. This is his best DX so far. The station who received his speech is 2AE, Mr Ratty, of Gisborne.