1931-03-12 — Page 2

HONG KONG DAILY PRESS, THURSDAY, MARCH 12, 1931.

RADIO

ARCTURUS

The Famous Blue Tubes

For Better Radio Reception.

Exclusive Features:----

LIFE-LIKE TONE. When you purchased your radio set, you expected to get clear, life-like reception. That depends on the tubes you use! The exclusive, advanced design of Arcturus Tubes eliminates mechanical background noises every note, every word, comes in with a vivid Life-Like Tone. With a complete set of Arcturus Tubes in your radio, you know you'll get unusually clear, brilliant programmes.

7 SECOND ACTION.-Arcturus Blue Tubes in your radio set bring in programmes in just 7 seconds -no annoying wait for programmes to begin.Just flip the switch, and by the time you turn the dial, the programme is there -quick, certain, as compared to the usual 30 seconds, or more, wait.

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WORLD'S RECORDS. FOR LONG ··LIFE, Throughout the world, Arcturus Blue Tubes are proving themselves to be the tubes that have established a world's record for long life. Because they withstand exceptional overloads that often burn: out other tubes. Arcturus Blue Tubes assure the user of long; satisfactory service.

Ask Us For Demonstration

THE SINCERE Co., LTD.

DISTRIBUTORS.

FEATURES

METAL BASEBOARD: VALVES WITH SOLID PINS.

SCREEN-GRID HIGH-FREQUENCY AND GRID-BIAS.

form

.a

satisfactory's component. The potentiometer to which the Valves, with solu pins, instead of

S grid leak retura of the detector is | the split or kianna type, are being There are other parts, such

chokes, and transformers, which issued in increasing numbers. ought to be examined before fitting taken is not intended as a volume When the valve holders are of them to the base. A single con- control, though actually it does give

Athe set extra sensitivity, sound design good contacts, and thet may rain all the valves. lasting ones, too, are readily ob-use dught; therefore, to be Etted

as a precaution.

tained.

But some holders are not satis-

factory. A flexible part must be provided in the socket itself or a firm contact will not be made,

No matter how precisely the valve bases are made, good contact I will not be possible with a socket that has solid sockets-with a plain hole in them. for if the contact is made fr it becomes difficult to remove and fit valves.

The solid pins are easier to deal with in manufacturing, than the split type. Any slight out-of-truth is bound to be more serious than in the ease of split pins, however, so that suitable holders must be used. Some holders are definitely not suitable, hilt there are many types that seem satisfactory.

Screened-Grid "and" G.B. ⠀⠀

A very useful refinement which oftea enables the last ounce to be. The matter of grid current in got out of a set is a .0001-miò, fix. amplifying valves is an importanted condenser, joined between the one. Many screened-grid high-

frequency stages are used without plate and filament of the detector grid-bins so that it is necessusvalve. (But use a good one, for. when possible to avoid valves which obvious reasons 1). pass a fair grid current when the grid-bias is zero.

Some valves pass much more thin others at this point, and eno would therefore expect the per- formance to suffer with a valve passing current as compared with another passing a lesser current

De

Detector or L.F. stages in which fairly high anode resistances are used will always need far more an it is H.T. at the battery plug than intended to apply to the valve, owing to the drop in voltage across tho resistances.

AC-SG3 Set.

ENTIRELY HAINS OPERATED

- A sensation in 8 valvo sets," with 1 wait undistorted output. enough power for any moving coil or dynamie loudspeaker. A set that will appeal to you whether you are interested in perfect quality from the local station or clear reception from distant stations.

Price only $145.00

Fucluding Masda Valves (the beal British Valves)

Special B ELIMINATUR for any domestic set or made to order for any requirements.

For

use

or

There are considerable differences between the grid-current character- A pointed wooden skewer istics of: valves, and these are re-broken lend pencil can generally be Rected to an extent in the other used successfully to start a ston! characteristics. If you plug in one nut on an inaccessible thread: valve, note the results, and then' A paint to hale is that with a valve try another valve and obtain differ- having sold pins slight bending is ent results Grid current may the only trick to be tried to over playing a part, A valve having a come a pear St. Bending is not heavy grid current at zero bins generally recommended, however. tends to broaden the tuning and to But may he tried in bad cases. Ideaden the circuit. must be remembered that the pins, though called solid, are really tubes, the contact wires from the bulh passing through them and ling saltered on: the tips.

Metal Baseboards.

The fashion of using metal bases for sets, upon which to mount the various component parts, is not without its dangers.

Care should be taken with the valve holders. Some are no con. atructed that when the valves are pushed home the pins touch the metál base and prevent reception. Other parts must also be watched take care of certain tuning-coils, they have torminals in their bases with too little olearance, with the result that contacts with the metal hase may occur. A piece of insulat ing material may be used to safe. guard the coil.

The contacts ought to be pro- perly countersunk in the base in

TELEFUNKEN

THE WORLD'S BEST RADIO EQUIPMENT

When grid-bias is used, such as negative . volt, the results are not likely to be so different. Provided there is no grid current at this bias, the valve, having most at zero bias will provide the strongest

gala,

SOME USEFUL HINTS.

A pair of phones in serics with a dry call makes an exceedingly sensitive and satisfactory test de- vice for checking continuity.

THE VATICAN WIRELESS

STATION.

A WORLD-WIDE RANGE..

If you spill acid on the carpet or clothes, neutralise it immediately with ammonis, soda, or bicarbonate of soda, liberally applied.

When a pick-up is inserted in the grid circuit of a detector valve whistling and distortion is often caused by unnecessarily long leads.

Although conversations on the Transatlantic, telephone may sound rather amusing, it is no infringe. ment of your receiving licence..to' make these conversations public

*

*

.Several Continental etations, in. duding Oslo. and Radio Lyon, pick up and relay English programmes to their own listeners ocasionally.

Roman wall to accommodate the feeders connecting the transmitter with the aerial.

A special receiver will secure. good telephone

and telegraph duplex communication between the The short wave broadcasting and Vatican City and any part of the wireless telephone and telegraph world, telephony being possible duplex atation which has been sup from any telephone installation fu plied by Marconi's Wireless Tele- the Vatican City. This receiver is graph Company to the Vatican situated in one of the rooms of the City, and which was formally in transmitting station and utilises augurated by His Holiness the vortical aerial placed at a distance Pope on February 12 has a world-of only a few yards from the rend

wide range

The station is housed in a sub

stantial one-storey, building near

ing aerial and suspended from the same triatic.

Every effort has been made to

the Vatican railway terminus. In harmonise, as far as possible, the

its main features the transmitter ransmitting buildings and serinl

This illustrates an All Mains set combined with loud speaker follows the design of the famous fowers with the graceful surround

GREAT SELECTIVITY

RECRIVES

Mauilu, Canton, Japan and Local Station. For Demonstration and further particulars apply to

·Marconi. short-wave high-speed | inge" of the Vatican City. The beam transmitters which are used transmitting building is of suber In the British Imperial Beam but pleasing architectural desigo, stations and it was manufactured The tops of the asta are finished at the Marconi Works at Chelms-off to give a Bishop's mitro 'effect which greatly enhances thoir ny ford:

The complete installation con-pearance in silhouette. sists of four thaid paneis, designed The new wireless station which in for telephony and high-speed tele- all respects represents the latest raphy on either 13.81 at 60.30 word in short wave technique to

SIEMENS CHINA CO. metres On telephony, the treas which such far-reaching contribu

Office-Pedder Building, 4th Floor. Showroom-97, Nathan Road, Kowloon.

TELEN

FUN KEN

Canton Ooo...SHAMEEN

UEUIL, BOZBE

TYPE T88 WL.

mitter is rated to deliver fromations have been made by Marchese. to 10 kwa of unmodulated carrier : Marconi and his able assistants has wave opargy to the Rerin) feeder been erected by Italian engineers system, the output depending under the personal supervision of slightly on the wavelength used. Marchese Marconi. It will not only On continuous wave telegraphy the provide the Vatican City with a rating is from 13 to 16 kwa, to the radio telegraph, and radio telephone, aerial feeder A special farconi line with distant parts of the earth, Lype of vertical short-wave aerial but, when required, will also en- is used for trapsmitting, there being able the voice of His Hohacks the separate acrial for each wave Pope, to be broadcant throughout length."

the world.

The transmitting room is situated During tests the Vatican station in a part of the grounds in the carried out good clear telephone Vatican which, in surrounded by communication with Australia, In- Roman wall 45 ft high, while the

masts, 200 feet in height, are pinced din, 8. Africa, Argentina, Canada, outside this wall. In order not to United States, and with London, destroy the amenities of the Vati Paris, Berlin and other European con gardena, a tunne) 141 feet long.

bue becha constructed under the capitals.

perfect reception

·MAZDA” Valves,

large stock newly arrived

RADIO batteries made by new process minimis. ing deterioration “PERTRIX” 150, 100, 45 volts and C. batteries.

Ebonite “TROLIT" and Tressed Fibre Panele out in any size. Loudspeakers, and various parts are also obtainable.

further information apply to

CANTON TRADING ASSOCIATION, LTD.

CHINA BUILDING (5TH FLOOR),

The

TELEPHONE 24610.

EVERYTHING.C.) ELECTRICAL

Mont Fustanica

COSIER FIRES

HOMES

FOR COSY HOMES

ELECTRIC

Magnet

An example from the complete range of Magurt Household Electric. Appliances

Irons Kettles Toasters

Cleaners Fans Fres

Washing Machines

Cookers Grillers.

Appliances for the

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MADE IN ENGLAND

FIRES

Magnet Fire

Current consumption 1 of 14, unke in bout Finthed in brown, blue, green, grey or white vitreous enamel.

THE GENERAL ELECTRIC Laling – Elctrical

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Sold by all

Dealers, Stores, 112.