RADIO TOPICS.

New Zealand Herald, Volume LX, Issue 18567, 27 November 1923, Page 4

RADIO TOPICS.

BY " THERMION." ADELAIDE TO BROADCAST. Although Australia has been somewhat backward in introducing legislation to provide for broadcasting there seems no doubt that now the necessary regulations have been framed and passed, the various interested parties are out to make broadcasting a success. A large amount of money is being sunk in the different high power transmitting stations now in the course of erection and according to their suggested programmes, entertainments of very high standard are to be given. What is to bo one of the largest stations in the Commonwealth is now under course of erection at Millswood for the Millswood Auto and Radio Company. The studio equipment will be of the elaborate type used by the best American broadcasting stations. A service is to be given or seven hours eac' day items being broadcasted for one and a-halihours morning and afternoon, at much hour, and m the evenings. The continuous range is said to be 500 miles, so that there will be little difficulty in picking up the enter tainment here in the evening and perhaps oven in the daytime. The programme is to include weather and market reports, bedtime stories for children, concerts lectures and Addresses, while arrangements have been made to broadcast, specia events such as addresses in the Town Hall. The station is duo to commence operations at any time now. There are at present no details as to wavelength, but, being a comparatively high-powered station, the wavelength, as in the case of Farmers, Lt<L. Sydney, is certain to he well above 600 metres. A wavelength of 850 metres baa been allotted to the Adelaide Broadcasters, Ltd., but presumably this is a different company. Apparently the Australian broadcasters are to be given entertainments of a quality .equal to that given in England and America, and the broadcasting stations are to be of such power that there will be listeners to these broadcast all ove- New Zealand. Receiving equipments ii. Australia aw to be seale< so that they are capable "of receiving on only the wavelengths of the particular broadcasting stations to which they make mi annual contribution .We are in the fortunate position of being able to listen to any of their stations without payment.

AMATEUR ACHIEVEMENTS. The Victorian amateurs are very jubilant over their successes in the recent transPacific tests, when messages were beard from more than 130 different American amateur stations. A station controlled bv Mi. Nikant, of Los Angeles, is reported to have been so consistently loud on two valves that Mr. Hull (3JU) made a successful dictaphone Teeord of the signals, an excellent accomplishment for a distance of 7000 miles. One Victorian experimenter received the Americans on a. loop aerial, buKthis is not a unique achievement, as a few of our Southern amateurs have been doing this for some time. It will be interesting to see whether the Australian amateur transmitting stations will succeed in communicating with the Americans. The first record of long-distance reception was made by Mr. Slade. of Timaru, who some time ago set New Zealand amateurs to the task of trying to pick up American amateurs, when he announced that he was hearing a largo number of them on a single valve. Mr. Slado is now in Dunedm, and owns the transmitting station 4AG. Mr. Edwards, or the local station IAA, reports that he has picked up 4AG very loudly on Morse, when the latter station was transmitting, using two ordinary receiving valves. V 24's, with 100 volts on the plates. Remarkable reception on loop aerials is becoming somewhat common. Mr. Bell. 4AA of Otago, ,has succeeded in overbearing messages passing between two Melbourne amateurs when using an indoor aerial 3ft. square. On this aerial also he has heard a number of the American amateurs.

NOTES AND HINTS. Considerable dissatisfaction is being expressed at present in England at the quality of the programmes being broadcasted, especially from the London station at. Marconi House. Listeners complain of the sameness of the programmes and the broadcasters will havo to devise novelties to hold their radio audiences. The distilled water of the storage battery should ,be kept just above the level of the plates. Any part not covered is inactive in supplying current with the result that the battery, not having its full capacity, will require sntojre frequent charging. . Australian enthusiasts are looking forward to a Radio Christmas as it is expected that their high-power broadcasting stations will all be in operation then. No great number of listeners can be expected during the summer months, but next winter should see these stations having a tremendous number of subscribers if the standard of the entertainments is kept to that of their tentative programme. Contrary to what the novice would expect better electrical contact is obtained by rubbing on the contact of a switch with the tip ox the finger a very small quantity of vaseline, and this prevents wearing of the contacts. This dodge is common practice in research laboratories (with .delicate measuring instruments. The contacts of the rheostat should not be oiled as the oil heats up and carbonises, giving a varying resistance at the junction which causes " frying " noises in the receivers.

There seems no limit to the future service to mankind to be given by wireless means. Transmission of photographs has been practically accomplished in America. Germany is in sight of a combination of wireless, bioscope, and gramaphone which will result in a synchronised talking film. Wireless controlled ships and airplanes have 1 een directed through various manoeuvres. Recently a case of sickness occurred on a doctorless ship and by means of the radiophone the heart beats of the sufferer were heard by a doctor several hundred miles inland, and the result was a correct diagnosis and cure of the case.

Two Wellington amateurs with transmitting plants are sending, for half an hour each evening, slow Morse for the benefit of beginners who wish to learn the code. There is an opportunity for local amateurs to give a similar service and assist to increase the interest of the novice in wireless.

When building a set be sure to obtain a good grid condenser and leak. These components are very important parts of the receiving equipment. Make the grid wires as short as possible and keep them isolated from other wires. The usual value for the grid condenser is .0025 microfarad, and for the grid leak 2 megohms. The latter should preferably be variable. No grid leak is necessary for soft valves, some of which do not require even a grid condenser. The best arrangement for any valve can easily be found by experiment. Newcastle, in Australia, proposes to erect loud-speaking sets in one or more of the parks so that the general public may hear entertainments broadcasted from Sydney and elsewhere. The City Council are moving in the matter, and the town clerk, Mr. Glassop, broadcasted from one of their local amateur stations an outline of the scheme. He requested all those who heard him to ring up on landline. It is said that Mr. Glassop had occasion to speedily regret his hopelessly inadequte estimate of the number who would hear him.

Where single cotton-covered wire is used for winding coils care should be taken to see that the insulation is in no way damaged. If it is, adjacent, turns may be short-circuited, and this gives rise to an undesirable effect. The radio frequency currents in the coil caused by the incoming signal will induce a large secondary current in the shorted turn and this causes a drop in the voltage across the coil and therefore lower signal strength. The same effect is given by some types of sliders on coils which are tapped by a slider.