RADIO AND ITS RECEIVERS

Sun (Auckland), Volume I, Issue 267, 1 February 1928, Page 12

RADIO AND ITS RECEIVERS

Conducted for THE SUN by

C. M. Taylor, B.Sc., M.I.R.E.

SHORT WAVES The Dutch short wave station PCJJ is now making regular transmissions on 30.2 metres on Wednesday and Friday mornings between 6.30 and 9.30 local time. This station has been moved from its original situation and has been rebuilt with much more extensive studio accommodation. IvDKA is still faint, but is there for those who tune in this pioneer station. RFN and the short-wave station of 3LO Melbourne can usually be picked up on Monday mornings, when 3LO does its weekly testing. BATTERY-CLAMP TO CLEAN WIRE An ordinary large battery-connec-tion clamp is useful to skin rubbercovered stranded hook-up wire. Merely file the jaws of the clamp smooth, and then cut in them, with a three-corn-ered file, a notch which is roughly the size of the wire. To use the tool, simply close the jaws over the wire to be skinned, squeeze with the fingers and at the same time pull outward toward the wire’s end. The edges of the notch will pare the rubber insulation off neatly without cutting any of the fine strands of wire. POLARITY TEST Slice an ordinary potato in half and inset two bare wires running from the battery terminals, or power unit, into tli.e raw potato about an inch apart. The negative wire will discolour the potato, the positive will not. The salt-water test may be conducted by making a saturated solution of salt water in a drinking glass. The two bare wires are inserted in the fluid and immediately bubbles will arise from the negative terminal-. Either of these tests are invaluable to the dealer or owijer of a radio set who desires to know the polarity of his power supply leads. THE DEALER AND HIS CUSTOMER The New Zealand Radio Record is making a feature of what the dealer ought to do to carry out his obligations to his customers. There is much good advice in these articles, but it appears to the writer that an assumption is first made that the New Zealand dealer is rather an ignoramus, both as regards business and radio. This is rather unfair, as most of our dealers have fostered both the technical and the sales side of radio, and in this respect are more responsible for the 40,000 licences than the Broadcasting Company’s programmes. A point mentioned by the “Record” is the extensive service the dealer is expected to supply. To go to the other extreme, one does not demand that same service of one’s tailor or shoemaker, and this service is keeping the price of radio up higher than it should be. To provide for the man who forgets to open his earth-aerial switch and demands a service man who has to be sent out in a taxi costs one of the local firms over £ 5 a week in overhead expenses, and if a preliminary training on the lines of a cardriver’s licence could be given to every new set owner, then it looks as though a great benefit would result all round. RADIO AND SUMMER TIME Generally speaking, the advent of Summer Time has had a detrimental effect on overseas reception, but whether this fact, which concerns a minority of the people of New Zealand only, is sufficient for its wholesale condemnation by some listeners is open to question. A similar outcry from gramophone users is almost to be expected, as the main question is the cutting short of one’s time for entertainment. The Australian stations certainly do not come on the air until 10.30 p.m., but against that we have the charm of radio in the garden and on the porch when it is still daylight. Personally, the time is 9.30 p.m. Sidey Time, and 2FC, 2GB and 2BL are coming in strongly for this time of the year. 4QG is weak, as is 3LO, and the strength of 3YA and 2YA i 3 not very much below that obtained during the winter months. It is very little to sacrifice distant reception for an extra'hour of daylight; still, this is a personal opinion, which is all for the new scheme of things. POWERFUL LOUD-SPEAKER Two developments on display at the Berlin radio exhibition stand out as greatly interesting tc electrical manufacturers in States, in the opinion of Herbert B. Pierce, electrical engineer and Berlin representative of the General Electric Company, of Schenectady, New York. “Of the two things at the exhibition of the most concern to the American electrical industry,” said Mr. Pierce, “one is the enormous Siemens loud speaker, which can so magnify the voice as to fill the largest hall, thus taking the place of several small apparatuses. Unfortunately the price of this loud speaker is about 4,500 dollars. Its power is so great that the Cologne Cathedral, which first installed one. had it taken out. “The other interesting thing is the Carolus process for picture transmission, which operates by a principle other than the Marconi system. Only time can show which is the better.”

KDKA HAS POWER OF 50,000 WATTS Announcement was made recently by the Federal Radio Commission that the power of KDKA, the Westinghouse station at Pittsburg, Pa., has been increased to 50,000 watts. The increase makes KDKA one of the most powerful broadcasting stations in the world. The station formerly operated on 30,000 watts. KDKA is known as the pioneer broadcasting station of this country. Although several stations previous to 1920 had sent music intermittently into the air, the Pittsburg plant was the first to inaugurate a permanent broadcasting schedule such as we now have. It also pioneered in the broadcasting of events of national importance. On November 4, 1920, KDKA broadcast the first ra'Gio election returns, and on the following July 4 staged the first air reports of a boxing match, the Dempsey-Carpentier light. PROPER USE OF RHEOSTAT In building a receiver employing radio frequency, the filament of each radio frequency tube should be controlled by separate rheostats. When the radio frequency tubes and the detector tubes are connected to the same rheostat, one of the tubes may be getting too much current from the maximum efficiency, while the other tubes may be working at their best. The detector tube requires a grid return to the A-plus. The amplifiers require an A-minus connection. When one rheostat is used to control all three tubes, the grid bias is controlled by the position of the arm on the rheostat. When .the bias is used for the detector it may not be correct for the radio frequency. The audio frequeqcy tubes are not critical to filament adjustment and may be controlled by one rheostat of proper value. NEW LAMP FOR TELEVISION A gas-filled electric lamp into which have been built several entirely separate sources of light has been developed by C. Francis Jenkins, Washington scientist, inventor and radio engineer, for use in improved apparatus for the reception of radio vision, which Jenkins first successfully demonstrated two years ago before a group of high Government officials. The invention has come about as a by-product of the larger effort in improving the present operation of apparatus for transmitting all receiving vision by radio, Jenkins stated. It was devised to overcome one of the most difficult problems in the receiving apparatus, and while its use is especially adaptable to the radfo vision apparatus it is likely, he said, that other branches of scientific endeavour will find it valuable. EMPIRE BROADCASTING SUCCESSFUL TEST FROM SYDNEY Hundreds of letters were received by the British mail recently, congratulating thei Sydney “Morning Herald," 2FC, and Amalgamated Wireless (Australasia), Ltd., on the success of the joint effort in broadcasting from Sydney an Empire programme, which was relayed in Britain on Sunday, October 30, by all stations of the British Broadcasting Corporation. Among the letters were a great number from listeners who had previously resided in Australia, and from Australians engaged on a holiday tour of Britain and the Continent. Mr. John J. Cooper, who was engaged in the Melbourne office of the Sydney “Morning Herald" in 1907, and is now in the Paris office of the National City Bank of New York, reports that the British relay was heard with wonderful clarity in Paris. He congratulates the pioneers of Empire broadcasting from Australia on their enterprise. The “laugh” of the kookaburra and the coo-ees of Mr. Smith were regarded by Australians as the outstanding feature of the broadcast, though, from the reports, it is evident that the music and speeches were, as a whole, excellently received in Britain, and on the Continent. “A RADIO MARVEL” The “Daily Mail” (Paris edition) stated: “All Britain and many listeners on the Continent last night heard dawn breaking in Australia. This fantastic marvel was achieved by the remarkably successful relayin'- from the Daventry stations and London of a wireless programme broadcast from Sydney, New South Wales. “Sitting by their firesides after tea., with the lights burning and the curtains drawn, tens of thousands of people, enjoying the tranquility of Sunday, actually listened to Monday morning in Australia. They heard the great clock of the G.P.O. in Sydney—more than 13,000 miles away—booming out the hour of four the next morning “As though it were some magic timemachine, wireless had transported them 10 hours ahead. At a quarter past seven in the evening, when daylight had faded from the west only one and three-quarter hours previously, they heard a voice saying: ‘lt is a lovely warm morning here. Dawn has just broken, and it is the beginning of a perfect summer day. It is now thirteen minutes past five.’ ”

TROUBLE OVER COPYRIGHT

“The action of the copyright claimants is most reprehensible, not only in claiming royalties on works over 90 years old, but in actually demanding royalties on monologues written by the individual performing them —a blind demand made with the expectancy that its browbeating 1 methods would intimidate the broadcasting stations into complying with its demand.” The foregoing appeared in a report prepared by a sub-committee and submitted to the Wireless Conference recently. The report stated that as the Copyright Act was passed before the advent of radio, the Performing Rights Association had been permitted to collect fees from broadcasting stations. which the Legislature had never intended. At present Performing Rights could demand any royalty they thought fit, and dictate as to what music should be given to radio listen-ers-in.

The proportion of revenue paid by broadcasting stations in Australia was more than double that paid in Great Britain, states the report, which expressed condemnation of the monopoly claimed under the Act, and urged the Government to end it. The conference carried a resolution demanding that there should be a registered copy of all copyright music made available for inspection by the public; that a maximum charge should be established on the minimum basis under which the combine can claim on all copyrighted items broadcast; and that proof of ownership of any item be first established before any copyright claim is made. Mr. G. A. Taylor, chairman, said that the author of that popular song, “I Was Dreaming,” had received only 25s in copyright fees. It was fairly evident, he thought, that the Performing Rights Association, and not the authors, benefited by the Copyright Act. NOISY GRID LEAKS

Carbon resistors are most frequently to blame when a hissing noise comes from the loud-speaker. The trouble may be traced to a grid leak, or to a plate coupling resistor. Sometimes the cause is a corroded contact and must frequently occurs at the positive terminal of the storage battery.

RADIO BREVITIES

Canada lias seventy-four broadcasting stations operating on 247. S to 516.9 waves meters. An outdoor antenna picks up from 10 to 100 times as much energy as the loop antenna. The season’s developments in load speakers seems to show a trend toward the horn again. Recent efforts of acoustic engineers have brought forward an improved horn which i* said to rival or outclass the cone. The new horn does not by any meins resemble the old “goose neck” type, is it generally’ is made up in a cabinet very similar to that which houses the cone. Keep batteries standing upright to get the longest possible life from them. A spider web antenna arrangemmt is employed by the Swedish. The wires are all brought to a central ring. From here they radiate to the roofs of many houses around. The lead-ins are taken off the centre of the wire. The high-resistance variable resistor in series with the antenna lead maket a handy volume control. The charging current of a storage battery of 100 ampere hour size should not exceed six amperes. If for any reason a storage “A” battery of the lead plate type is b® stowed away for some time it should be fully’ charged and the electrolyte removed. The electrolyte may later he poured in, the battery charged and put into operation. English miners may be compelled to carry miniature radio sets —recemUf and transmitting—as a means of communication in case of disasters. Radio development in Denmark **■ Norway’ is said to be undisturbed if atmospherics, static being almost unknown. The antenna should never be foffw” ten, as it is the source of many difflcwties. It must not run parallel to bip» tension wires. It should be well Insulated and the lead-in free from contort with any grounded object. Never permit the antenna to S® through the change of seasons without a thorough inspection. ConnactiflU* and insulators are bound to deteriorate