RADIO AND ITS RECEIVERS

Sun (Auckland), Volume II, Issue 475, 3 October 1928, Page 14

RADIO AND ITS RECEIVERS

Conducted fop THE SUN by R. F. HAYCOCK. Providing Variety RELAYS FROM COUNTRY Success in Australia

COMPLAINT lias often been made of the sameness of programmes broadcast from New Zealand stations, and lack of sufficient performers to supply the necessary variety has been the excuse. , There is something to he said for-this, but might it not be overcome by arranging to relay programmes from provincial towns?

It is suggested that it should not be very difficult for Auckland to relay concerts and similar entertainments from places like Hamilton, Cambridge, To Awamutu or Whangarei. Apart from giving Auckland listeners the opportunity of hearing new talent, added interest would be added to country listeners by hearing artists whom they know. Some of the more important sports fixtures played in the province could also be broadcast, and here again country listeners would be more interested in hearing accounts of those familiar to them. The idea has been tried out in Australia and has proved highly success-

ful, and as the result of the success of the recent week-end land line relay from Orange, quite a number of New South Wales country towns have been approaching the New South Wales Broadcasting Company, Limited, for dates. Arrangements have now been completed for a transmission from Lismore on September 22 and 23, and from Goulburn on September 4, whiJe matters are in train for broadcasting from Newcastle, Wagga, Albury, Wollongong and Bathurst. The transmissions will be carried cut through the service of 2BL. It would be interesting to see how such an experimental relay in New Zealand would be received.

TOO MUCH VOLTAGE A valve will become inoperative if the lUaments are subject to continuous overheatings. Most of the valves now in common use are of the thoriatedtungsten type. This type depends upon a surface layer of thorium oxide for its electronic emission, and this active layer is automatically deposited or formed on the filament when the tube is operated at a certain temperature. Overheating will quickly destroy the active surface coating and the result is a poor valve. For best results, it is evident that the valve must be kept at the voltage specified by the tube manufacturer. This may be checked with a voltmeter or controlled by the use of- any filament-control device.

BATTERIES AND POWER VALVES Power valves should never be operated from light-duty “B” batteries. Use only the heavy-duty size, of a good reliable make, and be sure to use the correct “C" battery voltage. The electrical characteristics of power valves are quite different from those of the customary amplifying valves. Power valves consume more “B” battery current and they require greater “C” battery voltage. The wrong “C” battery voltage robs the power valve of its ability to handle greater volume without distortion, resulting in operation little, if any, better than ordinary valves. In addition, if the “C” battery voltage is too low the “B” current consumed by the valves is multiplied many fold, which rapidly exhausts the "B” battery. Merely substituting a power valve for some other valves in the last audio stage of a receiver will not bring about any noticeable improvement in reception. Provision must be made in the wiring of the set to allow placing the correct value of “C” battery voltage on the grid of the power valve. These valves can be operated on “B” battery voltage of 90, 135 or ISO.

ATWATER KENT CONCERTS SUNDAY EVENING TALENT Atwater Kent, whose series of Sunday night. radio concerts is generally conceded to have raised broadcasting to new heights in America, has gone even farther this season in bringing to the radio public the finest available musical talent. In addition to retaining the headliners of previous series, he is this season presenting more stars of the famous Metropolitan Opera Company to the public. Nahan Franko, who for the first time conducts a twenty-piece orchestra in support of the Atwater Kent artists, was formerly conductor of the Metropolitan Opera Orchestra, with which he was connected for twenty-five years. Franko is the favourite oj New York’s four hundred. Another newcomer from the Metropolitan was Nina Morgana, soprano, who toured the country in concert with Caruso and is widely known. She has sung for Metropolitan patrons for the past six years. Giuseppe de Luca, baritone, broadcasting for the first time in the Atwater Kent series, has been with the Metropolitan more than twelve years. Benjamino Gigli, leading tenor with the Metropolitan for the past six years; Mary Chainey, concert violinist, and Mildred Seeba, winner of the Caruso Foundation award, are otheradditions to the list. Among the popular favourites of previous concerts broadcasting again this season are Reginal Werrenrath, America’s most popular baritone; Maria Kurenko, well-known Russian soprano; Albert Spalding, the American violinist; Alexander Brailowsky, Russian pianist; Margaret Matzenauer, contralto; John Powell, American concert pianist; Kathryn Meisle, contralto; Editha Fleischer, soprano; and Andre Benoist, pianist. These concerts are broadcast each Sunday night from Station WEAF, New York, at 9.15 eastern standard time, the complete network of stations following: WEAF. New York; WEEI, Boston; WRC, Washington; WASI, Cincinnati: WTAM. Cleveland; WGN, Chicago; WDAF. Kansas City; WFI. Philadelphia: WCAE, Pittsburg: WGR. Buffalo; WOC, Davenport; KSD, St. Louis; WWJ. Detroit: WCCO, Min-neapolis-St. Paul: Schnectady: WSB, Atlanta: WSM. Nashville; WMC, Memphis; WBT. Charlotte, North Carolina: WVOO. Oklahoma CityTula: WFAA, Dallas; WOW, Omaha; WHO, Des Moines. LOUD SPEAKER CONNECTIONS In certain types of loud speakers, the steady plate current decreases the strength of the magnetic field. This reduces the sensitivity of the unit and may ruin it permanently. If the leads are reversed, the opposite effect takes place. Use the connection which gives best results. Full-floating armature types may be connected either one way or the other, however. * CONCEALING WIRES Unsightly wires connecting to the radio set or cabinet may be placed out of sight by using a base socket of the plug-in type, a plug to fit the socket, and a short length of lamp cord. The antenna and ground wires are fastened to the base socket. The aerial and ground leads on the set are attached to the plug. When the set has to be moved, it is merely necessary to pull out the plug from the socket.

AERIALISMS

The antenna for the short-wave receiver should not be more than 50 feet long. Often a wire only 15 feet in length will be satisfactory and bring in signals half way around the world.

Weather conditions are often, responsible for the change of performance of the receiver. The set may work fine one day and then the following day act faulty. When the humidity is great, the decrease in sensitivity and selectivity is probably due to atmospheric changes.

A fixed condenser in series with the lead-in or ground has the same effect as reducing the length of the antenna. The smaller the capacity of the condenser, the greater is the reduction in wave length. The purpose of a series condenser is to sharpen tuning; that is, make the circuit more selective.

One of the most important things to watch in using the new A.C. tubes is to make sure that the wire used for making the connections to the filament is heavy enough to carry the required current. Rubber-covered twisted wire not smaller than No. 18 should be used. If obtainable, No. 16 or even No. 14 is to be preferred.

Scratching sounds heard in the midst of radio reception during a storm should not always be attributed to static. Where the lead-in consists of more than one piece of wire, The joints should be periodically examined for mechanical and electrical weakness, and places where the lead-in is fastened to the antenna must not be overlooked, for when the wires are strained and vibrated in a heavy wind noises will be heard if the joints are not firm.

HOW TO SOLDER A clean joint is one of the important factors of soldering:. Solder will not stick to any kind of metal unless the surface 6f the metal is clean. In some cases it is necessary to file, sandpaper or scrape the metal to be soldered in addition to using a good flux. The object in using a flux in soldering is not to clean the surfaces to be soldered but to keep them clean after they have been cleaned by other means. The dirt on a joint which is particularly inimical to good soldering is oil and oxide or other chemical compounds of the metal. Such compounds are very readily formed on the surface of the metal when it is heated, particularly the oxide, since there is always free oxygen around. The purpose of the flux is to keep the oxygen away from the cleaned surfaces and thus to prevent oxidation. Because of oil in the skin, keep fingers away from joints. Finger-prints do not make a good flux. Insulating wires of the enamelled type must’ be cleaned of all enamel at the point to be soldered before any attempt is made to connect them. This is best done mechanically with a knife or sandpaper, rubbing or scraping until the bright copper surface is exposed. Cotton, rubber or shellac covered conductors must also be mechanically cleaned before soldering, and in the case of some rubber-covered w*ire it will be found that a sulphate has formed that has practically destroyed the tinning on the strands. It is then best to clean down to the raw copper, as resin cannot remove this material in the quantities that will be experienced. Exercise care in soldering rubber-insulated hookup wire, as this insulation may melt and run into the joint. Heavily oxidised or dirty metal surfaces should be cleaned thoroughly with a file, sandpaper or scraper before attempting to make a solder before connection, and the same thing applies to nickelled surfaces.

PULL TOGETHER HELPING RADIO ALONG CO-OPERATION NECESSARY Broadcasting, more than any other industry, demands a very close and sympathetic co-operation between the various organisations contributing to the service. The broadcasting company cannot be blamed for all the dissatisfaction expressed by listeners, nor can it claim all the credit for the development of the industry. The wireless traders and the Postal Department have each a responsible share in the undertaking; and the establishment of the business on a basis of permanence and of continued satisfaction to the listeners depends on the degree of co-operation that exists between those three organisations. Many a fine programme, carefully worked out weeks beforehand and faithfully put on the air to the scheduled time, is spoilt for some listeners owing to causes beyond the control of the broadcasting company. The receiving equipment may not be functioning properly; the cause may be due to one of several things. The equipment may not have been properly designed for the particular purpose in the first instance, or it may have been installed in such a way as to produce a failure after a few weeks, unless careful attention is given to some part of the equipment. The listener himself may be to blame here; as often as not he is the blameworthy party in such failures, which have a nasty habit of occurring on the night when we invite our friends to hear a special programme. Unless the owner of the receiver takes reasonable care of his set and batteries, he is courting that kind of trouble. FAULTY SETS It is unfortunately a fact that there are too many sets in use that demand more than reasonable care if satisfaction is to be guaranteed at all times. Moreover, there are hundreds of sets in use that are incapable of a faithful reproduction of the music as sent out from the broadcasting station. The pity is, the Owners of many of these sets are not aware of the deficiencies of their sets, and thus blame the station for faulty transmission The fault, in the first place, too often rests with the trader who sold the set. Sufficient inquiries as to the location of the set when connected up were not made, nor was it ascertained if the operator was capable of adjusting a receiver containing components capable of introducing distortion or difficulty in tuning. Many sets of that nature are sold to persons as ‘‘cheap sets”; with their intricate parts calling for careful adjustment. Such sets should not be in the hands of the average broadcast listener. If not properly understood and operated, they may cause interference to neighbours listening as well as giving their own ers a quality of reproduction that is far from being faithful and pleasing. There is an obligation on every trader to do something more than sell his sets; he should ensure that the particular type of set being obtained by a listener is likely to give satisfaction for a reasonably long time without calling for more than ordinary

attention. It may be better to refuse to sell a particular type of set selected by a prospective listener who does not understand the proper adjustments. Every set that does not satisfy the owner becomes a bad advertisement not only for the trader but often for broadcasting as well. TRADE’S RESPONSIBILITY

While wireless traders have undoubted responsibilities to the business in the design and manufacture of receivers, the suiting of the sets to the particular needs of each owner, and the “servicing” of the sets to a reasonable degree after the sale, the broadcaster has his share conspicuously in the development of the industry. It is well known, of course, that there are some reputable traders who regularly attend throughout their organisations to the needs of listeners and the future of the business; but at the same time it is equally evident that all wireless traders do not take the same reasonable and sensible view. It is a pity that all wireless traders are not in a well-organised body for that purpose. The broadcasters have perhaps the greatest responsibility, for on them rests the burden of keeping the service up to a standard of such quality that it will retain the existing customers and' attract new ones. Coupled with that responsibility is the sphere of the Postal Department; to ensure that all listeners pay for the service they use, so that a sufficient and constant supply of revenue is available to the broadcasting company for the provision of programmes. The Postal Department also hafe the responsibility of ensuring peace in the ether, by regulating the wave-lengths of the stations and dealing as far as they can with the listeners who offend by careless or wilful use of radiating receivers. With a close co-operation between the broadcaster, the trader, the administration and the listener, and with a sympathetic appreciation of each other’s sphere, we can look forward to a happy future for this great community service.

GOOD JOB OVERDONE The duty of keeping the prongs of the valves clean can be carried too far. Sometimes these prongs are filed so much that the brass shows through. This may be all right in theory, but it should be remembered that these valves have to be put back into sockets that have not? been tightened to compensate for the metal filed off the prongs. Tight contacts are important in good reception and radical service on the valves may violate this rule. It is best to clean the valve prongs with a rubber eraser. IN SEARCH OF “DX” . The distance ability of a set depends upon the sensitiveness of the detector, the radio frequency valves, the antenna, ground and the weather. A loud speaker does not influence distance. Conditions of the weather are responsible for the absence of the distant stations, which are not heard as well in the summer as in the winter.

LOUD-SPEAKER POSITION If your loud-speaker does not wort properly where it is located, move it some other part of the room. To some extent every speaker h* B _ resonant frequency, or possibly se\erof them, at which signals are dispr® portionately amplified. Speaker., velopment work has centred largely, the problem of minimising tala quency discrimination. One thing that frequently “ elp ? $ trouble is a change in the locatio the speaker. A. sound wave offing at the speaker will travel to aor some object, be reflected ana aK strike the speaker diaphragm or ' * ing element. If this occurs at the right time it helps increase tc tensity of the vibration, and ben ® e sound. This results in what are as “standing waves.” This nCment entirely alters the characteristic of the speaker. ing the distance from the sp ? a *£, a nca the walls and other objects v/ill the emphasis on different notes. is one of the main reasons for na a speaker demonstrated in yoiir » and with your receiver. - i-. •