RADIO AND ITS RECEIVERS

Sun (Auckland), Volume 1, Issue 65, 8 June 1927, Page 10

RADIO AND ITS RECEIVERS

Conducted t>y THE SUN.

By

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

RADIANA

By the

BUZZER

An event of interest to all listeners took place last Thursday evening, when the Auckland Listeners’ League held its first annual meeting. The object of the league is to ensure good entertainment for all people who have taken up this latest form of amusement and instruction.

The history of broadcasting in Auckland has certainly been one of progress, but we have always been behind other countries in our progress. Some of my readers will doubtless remember the old IYA, with its five minute intervals between items for the valves to cool. Then with increased technical knowledge this difficulty was overcome, and a programme of good quality was presented on four nights of the week; to six nights and afternoon transmissions was an easy stage followed by the advent of the modern station with the final improvement wrought by the capable and popular Uncle Jack.

Where do we stand to-day? Many people think this progress is at an end and the A.L.L. has been formed to see this progress continued. One voice of complaint is that the resignation of Mr. Prentice has been accepted, and anyone who heard his talk on what King George means to us, to the children on the King’s Birthday, will regret the fact more than ever that his services are drawing to a close. Why is this so? Surely as the source of the company’s revenue the listeners are entitled to be told. UNSATISFACTORY WAVE-LENGTHS Another complaint is the unsatisfactory allotment of wave-lengths. When Wellington is on the air with its increased power interference is inevitable with the Australian stations; it is not a matter of selectivity, but actual heterodyning or heating will take place. Yet another complaint is the broadness of the tuning of the stations. Many reasons have been put forward for this broadness; technically it looks as though the aerial coupling was too tight. A popular reason is that the local stations do not desire comparison with the Australian stations, but that is manifestly absurd, as one has only to wait till after 10 o’clock. Still another reason given is that as the average crystal set is broad in its tuning, a station transmitting with wide sidebands is more easily picked up. If this is the company’s idea with the object of getting the first 40,000 listeners mainly from crystal owners, it certainly deserves some consideration, as the crystal user is limited mainly to the local station, and that station being his only source of entertainment should be of easy access to him, but they must remember that the crystal user of to-day is the valve user of tomorrow, and surely the quickest way to get the required number would be to give programmes which would appeal to crystal user and valve user alike. Listeners who heard 4QG broadcasting from the bottom of the New Chum No. 3 Colliery had a treat in the acoustic properties of the mine. There was that natural- clarity which is so often lost in the studio by excessive draping of the walls, and in this respect it is of interest that 2LO London has special echo rooms for special types of transmission. PROPOSED RELAY Station WLW, Cincinnatti, is broadcasting a special programme for New Zealand listeners on Sunday, June 26. 3.00 a.m., U.S.A. time, which is 8.00 p.m. New Zealand time. The wavelength is 52 metres, and the power 250 watts* Here is an opportunity for a re-broadcast by the local station, especially after the work done by 2BL Sydney in relaying London and then Holland and by 2FC Sydney In relaying WGY New York.

I am sure there are many short-wave workers who would be glad to assist in such an event, and which would especially appeal as the time in New Zealand is 8 p.m., and the Australian re-broadcasts took place in the early morning—and these mornings are cold. Station WLW has a very splendid studio complete with all the modern mechanical musical instruments, in addition to those usually used.

Station SCL Adelaide and 3AR Melbourne have been at excellent strength during the week. The latter station is not much sought, and the howling valve menace is completely absent, so “howlers” please continue to keep off.

An interesting and instructive table is to hand, which gives a pictorial representation of the chaos existing under the present wave-lengths. The table shows the spacing of the New’ Zealand and Australian stations on a wave-length, and for the more profound also on a kilocycle basis. It must be remembered that the transmission has not a definite wave-length but has side bands roughly five metres on each side of it. These sidebands vary in width with the degree of modulation applied. Thus we see that 3YA, on 405 metres, will extend from 400 to 410, and SCL, on 395, will extend from 390 to 400, which will mean interference. Similarly 2YA, Wellington, on the proposed 380 metres, will be between 375 and 385, and 4QG, on 385, will he between 380 and 390. A worse case still is with 4YA and 2FC, if 4Y"A is put up to 442 metres as suggested.

RADIO VARIETIES In St. Luke’s Hospital, Chicago, the avoiding of mental shock to patients having an operation with a local anaesthetic is obtained by’ the installation of a loud speaker beside the operating table, and the patient is carved to a musical accompaniment. The effect of an accidental transmission of the Dead March is not stated. Another American use for radio is the testing of the ignition system of a motor-car. It is said to pick irregular troubles at once; for instance, a broken down condenser in the magneto will only be apparent at certain speeds, but this short is apparent at all speeds with this new device, which is merely a valve circuit with the grid connected to the aerial, which is 25 feet long, and the grid and plate circuits inductively coupled. A stage of Audio amplification is added. Anyone interested can get the circuit and description from the writer. 3LO Melbourne is moving its studio from Collins Street. The whole move will take place in one night without affecting the transmission. The announcer at 2FC, with his years of experience, states that the only way to be successful in the studio is to make the miscrophone your audience, and “woo it as you would an actual audience, and don’t dismiss it as a dumb absurd piece of mechanism.” The Irish Post Office has decided to supply a broadcasting station for Cork and to locate it in the city gaol, which is now fortunately not required. The local force does not hold out any’ immediate hope for Mount Eden. In Holland telephone subscribers can listen in to concerts, the receiver and amplifiers being located at ‘ central.” If a message for the subscriber comes through the broadcast service is automatically cut off until the conversation is finished. The difficulty of neutralising the ever popular Brown-ing-Drake circuit over the complete wave-length range of the receiver has been solved by a device called the “Phasatrol,” which appears to be a resistance-capacity device. The writer as one of the original Browning-Drake builders in New Zealand, would be glad to hear of any reader having seen or used this device. British exports of radio apparatus make interesting reading. A few figures are given below for six months ending March, 1926:—Russia, £75,000; Japan, £145,000; Brazil, £34,000; Holland, £67,000; Ireland, £70,000; Australia, £279,000; New Zealand, £43,000; United States, £20,000; St. Helena, £IS. Australia and New Zealand took 25 per cent, of the total exports.

ISSUES OF LICENCES TOTALS TO DATE (From Our Oxen Correspondent.) WELLINGTON, Tuesday. Radio licences issued and renewed throughout the Dominion show a total of 19,579 licences registered up to June 2, comprising 18,326 listening-in, 1,155 dealers, and 98 transmitters and receiving. Licences were distributed as follow: Auckland, full-time 7,894, part-time 1,039, total 8,933; Wellington, 3,238, 109, 3.347; Canterbury, 3,988, 618, 4,606; Otago, 1372, 68, 1,440. The totals were: Full-time 16,492. part-time 1,834. Grand totals, 18,326. Dealers’ licences number 351 in Auckland. 197 in Canterbury’, 132 in Otago and 475 in Wellington.

Wave-length Station. Kilocycles. Station. Metres. — 1500 — 200 — 1400 — 250 — 1300 — 300 — 1200 2GB — — 1100 2BL — — 350 3LO — — 1000 2YA — 4QG — 5CL — 2GB — 3YA — — 400 — 900 1YA — 2BL — 4YA — 3LO — — SOO 2FC — 2YA — — 450 4QG — 5 CL — 3 Y A — 1YA — — 700 OAR — 4YA — 2FC — * — 500 3AR — — 600 7ZL — 7ZL — — 500 — 550