RADIO AND ITS RECEIVERS

Sun (Auckland), Volume 1, Issue 83, 29 June 1927, Page 8

RADIO AND ITS RECEIVERS

NOTES AND COMMENTS The Broadcasting Company Speaks.— Listeners the other evening were pleased to have an official from IYA at last announce something definite. The words, “Never mind, let 'em wait,” ringing clearly out through space were the first definite piece of information that has been given during the time the company has had control of New Zealand broadcasting, and as such all are truly thankful. Reading a paragraph in our evening contemporary about nasal artists and nasal filters, it seems a pity that one of the conditions of the appointment of the new announcer at IYA is that his diction and enunciation shall be good pure English, no fancy touches, but just “English as she is spoke.” This would surely be much more desirable to everyone concerned than proficiency in book-keeping and all the other little fancy touches needed. Still, one more point—surely Saturday's transmisison was the lowest ebb yet reached. The studio pianist, a singer, a guitar duo, and jazz and intervals, the latter being in several cases well over five minutes in duration. Someone blundered somewhere, as no one in his most sanguine moments could imagine Saturday’s programme would be pleasing to anyone. Sunday’s relay of the West Street Church of Christ was a peace offering indeed, being one of the best relays heard for some time. It merely goes to show what can be done.

A Successful Relay. —Listeners who were listening to 2BL on Saturday night had a treat in the relay of WGY, New York. Sousa’s famous Band was playing, and the rendering of “My Old Kentucky Home” was magnificent. There are so many interesting things to listen to that, as so many of them are unannounced beforehand, one needs half a dozen sets, each tuned to a different station, so as not to miss some special stunt. Tracing Trouble in a Factory-built Set. —When a set fails to deliver signals, the cause may be one of many. First of all test the batteries; every set should have a small double-range voltmeter on hand, B batteries have a habit of going dead quite suddenly;: the set is O.K. when last used, and absolutely dead when next turned on. If the voltmeter reads the full voltage of the' A battery, and the valves light, the A battery circuit may be dismissed for the present. The B batteries should show at least 37 volts for each 45-volt block if satisfactory service is to be obtained, although the set will function at valves much below this figure. Now remove all the valves, and all battery connections, and proceed as below: Connect up your voltmeter in series with a B battery, and have two leads with bared ends for touching to various parts of the set. A reading of the voltmeter denotes continuity of the circuit tested. Grid of radio frequency sockets to A

circuit; aerial grid coil and secondary of R.F. transformers; grid of detector socket to A; secondary of R.F. transformer. Short the grid leak before testing. In some sets the plus A must be substituted for —A in this test, therefore try both. Grid of first A.F. socket to —C, use lowest —C voltage; if M.O.C. battery use —A. Secondary of first A.F. transformer. Grid of second A.F. socket to highest —C or —A if M.O.C. battery. Secondary of second A.F. transformer plate of R.F. sockets to plus 90.45, whichever is used on the R.F. amplifying valves. Primary of R.F. transformers. Plate of detector socket to x 45 or 22J. Tickler coil if there is one and primary of first A.F. transformer (plate of first A.F. socket to plus 90. Primary or second A.F. transformer —A to each filament of each socket in turn; one should be dead and the other live, with switch and rheostat on. An irregular reading will draw attentfon to faulty switch or rheostat. Repeat with plus Ato the filament which was dead when the —A was used. If aerial, batteries and speaker are 0.K., the latter may be tested across the leads used for the set test. The set should be connected up again, and each valve replaced in turn, with the spare valve which every set-owner keeps on hand or decides to when he blows a valve on Saturday evening. If no good results, it is a case for the trained radio mechanic, particularly one who knows the set in question. Weak signals and oscillation mdiy follow the replacement of a R.F. valve with one of a different make, and the set should be reneutralised. Here the handbook should be consulted, or, failing that, a friend who understands the process, or, again, the dealer. These directions might be amplified to a very considerable extent, but the above should give an indication to the commoner types of failures. The relay from WLW was given simultaneously from 2FC and IYA, and the writer developed into a real “dialtwister,” and, thanks to a selective set, was able to jump from IYA to 2FC in a moment. From the point of view of a novelty it was very interesting, but both stations rather overdid the time allowed to it, considering the quality of the relay. The local authorities are to be congratulated on their enterprise, and deserved better atmospheric conditions. Still, there is hope for us, as our announcer, after a particularly bad burst, asked listeners to stand by whilst they cleared things up. All readers would like this receipt, I’m sure.

Dial-twisters. —That glorious hour of inglorious listening! What would you say of a man who rushed into a concert at the Town Hall, listened to a portion of a cornet solo, tore out again, dashed round to His Majesty’s, listened for five minutes to the comedian, hustled out, and round to the Regent to hear half of a baritone solo, then into top gear and a non-stop run to hear a talk on women’s rights from some local hall. You would be pardoned for questioning his sanity, and you would certainly be justified in claiming that he could not possibly give a proper opinion of any of these entertainments. Yet many listeners, whose sanity is not questioned, do in effect precisely what this comparison suggests. After the aerial trip, what do these dial-twisters say? “Programmes! —terribly poor. Why don’t they buck them up?” The question whether the programmes are deplorably poor or superlatively good is irrelevant to the point here discussed. The merit of a broadcast entertainment, like the merit of most forms of musical entertainment, lies in continuity, and each programme broadcast is prepared or should be prepared with the idea of giving the necessary variety, with due proportion of various types of entertainment, and the whole is so designed to be judged as a complete entertainment, and it is only fair for it to be judged from this standpoint. It would be unreasonable to suggest sticking to one station for the whole evening, but in criticising a programme it is hardly fair to praise or condemn it on one

Conducted for THE SUN By C. Mm Taylor , B.Sc.,

item, and of course programmes can be uniformly bad or uniformly good. If the “dial-twister” has an oscillating valve, what then? We have his squealing track flashing across our entertainment, spoiling and distorting. Radio Varieties. —TVhen the plate generator of KFRC burned out during the afternoon programme, the station was on the air again that evening, the emergency supply being a bank, of 150 heavy-duty car batteries, the largest bank of such batteries ever used for radio purposes.

A new valve, designed to work on A.C. or D.C. for both filament and plate supply, has been brought out in America. The new valve fits standard sockets, and functions by means of a heater, which is not in metallic contact with any part of the set. The heat generated is conveyed to a thimble of nickel, heavily coated with oxides of high electron emission. A connection is made from the thimble to the two A battery terminals of the standard base, forming the grid return connection to the receiver, thus eliminating any wiring change in the set. The other elements are the usual grid and plate. The inventor claims no decrease in signal strength, a 100 per cent overload can be successfully carried, and no effect from fluctuating line voltages.

ANSWERS TO CORRESPONDENTS Mr. N. Walding, of Mount Eden, has an ingenious method of balancing up the losses of a “hay wire” broadcast receiver so that, with suitable plug in coils, he can use the set on the low waves down to 25 metres. The most interesting point is that a plug-in radio frequency transformer is used efficiently on these low-wave lengths, the priimary being 39 inches of 20 enamelled wire, and the secondary 36 inches of similar wire; both are wound together on a two-inch former, and used with a plug-in socket. The next feature is the removal of the grid leak and the shunting of the secondary of the R.F. transformer with a variable o—s megohms grid leak. The circuit used in the ordinary three-coil with regeneration on the radio valve. H.J.K., Colson.—Would suggest a run-down C battery, or a leak from the transformer windings, to the frame of the transformer, if, as you say, the windings and B battery are O.K. Disconnect transformer and test. WITH THE RADIO TRADE Messrs. Waterworth sent THE SUN a Ureco D.X. 200-valve for test. The valve is of the modern gas-filled type, operating preferably with the grid return connected to the negative filament. The results in a standard factory-built set were very good indeed. On local stations little difference was noticed in contrast with the 201 A type, but on weak signals, as the Australians’ in the afternoon, the value of this detector valve was soon apparent. The filament voltage was five, and current taken was just under the rated .25 amperes. The valve took a short time to settle down to work, but the hiss which is a disadvantage of this type of valve was able to be turned much lower after the valve had been in use about three minutes. For the D.X. enthusiast nothing could be more acceptable.. IZQ was on the air on Sunday afternoon, with increased power. Mr. Keith’s transmission on Sunday afternoons fill an empty space in our times of transmission, and his extra power should bring him the thanks of many listeners. Mr. E. C. Gough, 8.E., representing Weston Instruments, was in Auckland last week, and the new ranges of precision instruments made THE SUN’S representative wish for five minutes of Henry Ford’s daily income. A.C. ammeters, voltmeters, and milliametres of the popular 301 class are now being made, and a very neat dealers’ service set which enables a valve to be removed and a plug placed in the valve socket gives readings of all circuits connected to that valve, using the set’s own batteries.