1931-05-07 — Page 2

HONG KONG DAILY PRESS, THURSDAY, MAY 7, 1931.

**

TADIO

Hear the Golden Voice

FROM THE NEW

ATWATER KENT RADIO

our Radio COME to

Department and let us demonstrate to you the new features of Atwater Kent Radio... Tone Control . . . Quick Vision, Dial... Mastery of everything on the air and many other vital points that will interest you.

Listen to our Atwater. Kent record. Hear how a great orchestra is build up-instrument by instrument--until all parts are blended into Victor Herbert's "March of the. Toys." You will enjoy this treat and feel. marvellous. Come in No obligation.

Decide for Yourself about Tone!

THE SINCERE CO., LTD.

SOLE DISTRIBUTORS.

FEATURES

SUPER-HETERODYNE THE SET OF THE FUTURE.

SLOWER MOVEMENTS OF CONDENSER DIALS REQUIRED.

A fairly common fault with dual- range coils, even in these days, is that the long wavelength part acts to destroy the effectiveness of the pedium wavelength part over & portion of its range.

LO

"'

The difficulty, in part, is that the coils are made of fairly high resist ances in order to help ganging. Then again, the tuning condenser may not tunc accurately over the whole range, due, perhaps, to fault in manufacture or to wrong setting up by the user.

What is happening is that the long wavelength winding, when shorted out or left out of the gir cuit, as the case may be, in tuning Realising these matters, it is not a medium wavelength. This difficult to understand why design. wavelength is determined chieflyers are turning their attention to by the inductance of the coil and the superheterodyne receiver, the self capacity, to which must be There is one, using six valves, added the circuit enpacities.

which is as cheap to build and to You will find when this fault is use as in good-class three-valve set. present that over A part of the Tuning is easy. Dozens of distant medium wavelength band much stations are brought in at full load more than the normal amount of speaker strength. Quality is good reaction is needed. Sometimes, in and the construction is so easy that really bad instances, the circuit can it might well be said to be more not be made to oscillate at all over easily built than some three-valve part of the tuning range.

scts. This is obviously the set of the future.

The fault is not too easily re- moved 'in made-up coils. Shorting out the long wavelength part, when this is not already effected, will often remove the trouble.

In other cases the addition of a fixed condenser across the long wavelength part will so alter the tuning that the trouble disappears. With a faulty coil you get brond tuning, poor signal strength, and the tuning is difficult.

Need of Selectivity.

If you were to ask your keen wireless friends what is the chiel fault with most sets, they would say, not enough selectivity.

The fact is that most receivers have much too poor a tuning curve. Reaction helps, of course, but not to the extent often thought. Our sets, with their one or two, screen- grid stages and three, or perhaps four, tuned circuits, provide not enough selectivity for the magniäga- tion available.

TELEFUNKEN

THE WORLD'S BEST RADIO EQUIPMENT

This illustrates an All Mains set combined with loud speaker

GREAT SELECTIVITY

RECEIVES

Manila, Canton, Japan and Local Station.

For Demonstration and further particulars apply to

SIEMENS CHINA

Office-Pedder Building, 4th Floor.

Showroom-27, Nathan Road, Kowloon.

TELE

FUN

KEN

Canton Offloo..SHAMEEN-

Swatow

...GERE. ROESE

A Pick-up Point. There are several ways of con- necting a gramophone pick-up to a set, some, of course, being cheaper

than others. Results will be ob

tained if the two wires from the pick-up are connected to the ends of the grid leak which is joined to

the detector.

Owing, however, to the varying load of the grid circuit of the valve upon the pick-up the reproduction is usually not considered good enough. The grid circuit of the valve, passes current and the value of the current varies with the volt-

Thus

age set up by the pick-up. the effective land is varying all the time and distortion results,

Connect one side of the pick-up to the grid of the valve and the other side to the grid-bina, battery thus the valve is used as an 'am. plifier with negative bias when playing a record.

A bins of 1.5 volts is usually suf Scient and the high tension applied to the valve mast be of such a value that the valve is able to work as an amplifier. Iri some instances the normal voltage used for detection is not quite enough for amplifica tion with grid hias and this point must be watched.

Poor Wander Plugs Many faults and cases of poor reception are to be traced to the wander plugs. Some of these are so shaped that a good contact with the sockets of batteries is not pos sible.

Others, ngain, have the connect- ing wires fastened to them awk. wardly, so that a poor or intermit tent contact is obtained. There are good plugs, and they cost but, little Dure than the inferior kinds.

New Dials.

With the super-heterodyne circuit- back in favour again, slow-motion- dials with better and slower move-

ments will have to be brought out.

factly satisfactory in many respects, The types now available are per-

for standard three and four-valve sets. Bat the super-heterodyne set tunes 50 sharply that we can do with betler tuning movements. When a station is in and gone in a part of a degree, something really good in tuning movements is need- ed for the best results.

HAVE YOU HEARD THESE?

Here are lists of long-wave and short-wave stations which should be picked up by anyone in Hong Kong who has a mode- rately good set suitable for, re- ceiving such signala. Success in picking up these stations niss dependa very largely upon fav.. curable atmospheric conditions." Readers are invited to add to this list should they succeed In picking up any station not in- cluded in either of these lists.

LONG-WAVE STATIONS.

Call Kilo- Sign cycle K.Z.I.B.. 1,158 K.S.M.S. 1,063 1,070

C.R.C.

Ways length (Metres) Station

200 Manila 277 Shanghai 980 Ticatsin 310 Shanghai K.R.O. 907 320 Peping C.O.P.K. 945

J.O.A.E. 345. Tokyo

870' 953 Hiroshima J.O.F.K. 800 355 Hong Kong Z.B.W.

640

157 Hembay V.U.B. 840 301 Sappore J.O.I.X. 300 Keijo

370 Nagoya

370.4 Calcutta

830

J.O.D.E. 820 J.O.C.K. 810 V.U.C

809.8"

380 Kumamoto J.O,G.K. 790

300 Sendai

355 Dairen

398 Rangoon V.U.R. 400 Danka

J.O.H.K. 770 J.D.A.K. 760

754

410 Canton 413 Manila

J.O.B.K

C.M.B. 789 K.Z.R.M. ***B

760

SHORT-WAVE STATIONS.

TIK (HONG KON

STATION

CALL 810

OF WOLKING -

Kootwijk (Ilollard) P.C.L

K.SAPI.

2.D.L.

8.1.0.

W.2.X.A.E

31.20 Eindhoven (Holland) FC.J.

CTCLEA

4,434 Mon, Wed. & Fri, 6 p.m. & 2 mi

4,000 610 p.m. 8,201 Not regular

0,000 Tue, Thurs, Sat., 8 p.m. 0,990 Sunday midnight. 7,142 Daily 6.30 p.m. & 11 p.m. 7,810 Not regular

7,730 Daily 1 p..

8,108 Tues, & Fri., 9 p.m.-1 am.

9.230 Not regular

9,503 Not regular

9,530 Daily 7th

9,020 Fri. 8 a.m., Sat, 9 am, & 10a.m.

50.

Mosco

57.65 Dobiatz (Germany) A.F.K. 60.12 Khabarovsk (Bussin) | K.A.07. 56.7 Nationw

A.G.J: EF.N.

CO.

43.5

Rome

1.M,A

42. Porth

6.A.G.

41.8 Singapore

V.S.1.A.B.

20.8

07.

Bangkok (Siam)

82.4

Sydney

81.55 MelbouEB

81.48 Schenectady

81,09 Sydney,

2.F.C.

9,600 Not regular

81.

Nairobi (Konys)

7.L.0.

9,677 Midnight dafly

29.6 Bydney

2.M.E.

10,626 Not regular

27.3 Bandoong

P.L. R

11,020 Midnight-3 a. daily

25.03 Chelmsford (England) 5.5.3.

11,761 7.80 p.m. & 8 am, daily, except

Saturday and Bunday

24.6 Manila

K.1.X.H

12,240 Nightly

23.35 8cbenectady

17.2.X.0.

12,860 4 a.m. Wod., Fri, Sat.

18,88 Bandoong

PLO

18.4 | Kootwijk (Holland)

P.C.I

TELE

17.1

Bandoong

P.L.F.

FUN

18.0

Bangkok

10,3

Kootwijk (Holland)

15.74 Bandoong

1.8.1.PJ. P.C.K. PLE.

17,761 Sundays 7 p.to & midnight

10.220 Daily 5.30-7 p.

15,5

Nancy (France)

10,861 Dally Bam.

13,93 | Pittsburg

W.8.X.X,

21,640 Not regular

10,102 Daily 030 pm to midnight

10 304 Daily 7 p.m.

17.280 Daily 8 p.m. to midnight

18,404 Each afternoon

AC-SG3 Set

ENTIRELY MAINS OPERATED

A sensation in 3 valve sets, with 1 watt undistorted output; enough power for any moving coil or dynamic 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

Including Marda Valves (the best British Valvesj

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

usė

For perfect reception MAZDA" Valves, large stock newly arrived

RADIO batteries made by new process minimis- ing deterioration "PERTRIX" 180, 100, 80, 45 volts and C. batteries.

Ebonite "TROLIT" and Pressed Fibre Panels cut in any size. Loudspeakers, and various parte are also obtainable."

For further information apply to :-

CANTON TRADING ASSOCIATION, LTD.

CHINA BUILDING (5TH FLOOR).

TELEPHONE 24610.

EVERYTHING (9.E.C.) ELECTRICAL

gout Puarantee

COSIER FIRES

FOR COSY HOMES

ELECTRIC

Magnet

An example from the complete range of Megast Household Electric Appliances Irons Kettles Toasters Cleaners Fans Fires Washing Machines Cookers, Grillers. Appliances for the

Toilet etc

TIRES

"Magnet Fire

Current consumption x or x3 undis an hour. Finished in brown, blue, green, grey or white vitreous gñaznel

TYPE T83 WL.

(Allowance must be made for “summer-time" in mort Buro- pean countries, which is one hour ahead of true time.]

MADE IN ENGLAND

by

CO. LTD.

Sold by his col

Dealers, Steras, etc.

THE GENERAL ELECTRIC leading Electrical