1930-05-22 — Page 2

THE HONG KONG DAILY PRESS, THURSDAY, MAY 22,

1930.

For Better Result

TRY MULLARD

IM.

THE BEST BRITISH MAKE

THE

MASTER VALVE

British & American Bases Available

SINCERE'S

SOLE DISTRIBUTORS

RADIO

FURTHER

FEATURES

DEVELOPMENT OF THE

VALVE.

SELECTING A COMBINATION.

Discussing the early development of the valve last week, it was stated that after the acceptance of the three-electrode tube the next step by manufacturers was to design a valve with characteristics suitable for that part of the receiving-circuit in which it was to be employed.

Receiving-sets not having reached the high degree of afficiency they have to-day, there was little to be pained by this distinction, and the "general purpose" valve of the R type found its way into the majority of sets in each stage.

quired for the flaments.

[Br" COHERER.")

At the present time, so,wide is the range of valves that can be used with a two or four-volt ac cumulator, that there is little to be gained by the use of the six-volt series, unless considerable power output is required and means avail- |

of the supply able for the use mains.

The Bull Emitter. Radio enthusiasts of some years' standing will remember the earlier a brilliancy valves us giving off sufficient to illuminate £1 small room.

A later developmen: dwelt on the

The current required by such economical aspect of valve receiv

rs, and steps were taken to reduce valves (some taking as much as both the voltage and current re-lamp) not, only" necessitated large cells but frequent charging, thus making the upkeep of a three or four-valve set a rather costly affair. It was about six years ago that market, a valve whose filament,

The first valve required from 6 to $ volts to heat the filament, and

With improvement in receiver de- sign the general-purpose valve is no longer a useful stand-by, and some care has to be taken in choosing a combination of valves if the full valve of their capabilities is to be obtained.

Bre

To work out the current im- pedence required for each compon- ent on the market would take some reams of paper, but constructors will not go far wrong it the follow- ing are used as a basis:-

High Frequency Coupling. Transformer Ratio. Impedence.

60,000 40,000

......

*............. 30,000 For resistance-capacity coupling the impedence should equal one quarter of the value of the resistance, and for L.F. transformer coupling 6fteen to twenty-five thousand ohms should be the approximate figure for the

valve.

more

Manufacturers of the modern type of loud-speaker usually specify the type of valve most suit- ed to it, but for the ordinary high- im- loud-speaker an resistance pedence, of three to four thousand ohms will be found quite suitable.

Selecting the Valve.

Reading Valve Data. Choosing the most suitable valve for a certain type of receiver is rendered easy when the data that is supplied with every valve is Unfortunately. the understood.

which slips of squared paper on makers curves

draws and figures tabulated convey nothing to

Having decided on the impedence the majority of radio users, and most prefer not to be bothered with it only remains to select a valve For those who offering the highest amplification their meaning. possess a factory-made aet this is factor for that Bgure, when, with safe enough, it being only neces- duo consideration to the current sary to specify the type or number consumption, the valve may be The home constructor, however, The two main features in valve shout base his choice on at least Resign of the last year or two are

the Pentode and the Screened Grid two of the figures supplied, name- ly, those of the impedence and The former has already been dis amplification factor.

cassed in these' columns, and the latter will provide the subject of next week's article.

for many years any lower voltage the dull-emitter first came on the of a valve when renewal is required.selected.

appeared useless.

"

A good deal was to be gained in theme of a lower voltage filament, as mains-operated sets were then unheard of, and weighty accumula- tors presented an item of some con.

sequence when having to be carried

about for charging.

Valves requiring four or two volts were next designed, and although they perhaps hardly had the eff eleney of the six-volt series there was a lot to he said for them from the economical point of view.

BUY BRITISH & BE PROUD We have just unpacked a Shipment of

ALUMINIUM BASE-BOARD & PANELS. Suitable for Short Wave Receivers and other seta

#

that require Screening &

OTHER RADIO & WIRELESS PARTS

(Guaranteed British Made).

ORIENTAL COMMERCIAL & Co., LTD. BANK OF CANTON BUILDING, TEL. 24405.

specially treated with thorium,

gave high emission though taking a comparatively low current.

This type of valve has been greatly improved upon. so have day practically all receiving-valves are of the dull-emitter type, some taking a current of only .06 ampere. Advances in valve design of more recent years have concentrated on the amplification factor or stage

gain

Only a few years ago an ampli- fication of thirty or forty per valve stage was considered quite

13

achievement, and caused a greater sensation than the recent claim of & stage gain of 500!

It is the ratio of these two which gives that much advertised term "slope." In all cases the valve must be selected to suit the com ponents of the set; in other words, its characteristics must be such as will work correctly with the corn. ponent in its plate circuit.

Thus, a power or last-stage valve will be chosen with reference to the loud speaker it is required to work, while for a low-frequency amplifier the valve of the coupling trans former on resistance will determine the characteristic required of the valve.

Valve Impedence.

QUERY CORNER.

TO-DAY'S WIRELESS

PROGRAMME.

BROADCAST BY Z.B.W. ON

355 METRES.

programme,

11 to 11:30 am-Commercial News. 11.30 am to 12.30 p.tn-Chinese

12.30 to 2 p.m.-Programme of » Victor records supplied by

Meaara Tsang Fook Piano Co. to 6.30 p.m.-Aunty Letty and Aunty Joy will entertain the Children.

6

WIRELESS NET FOR CRIMINALS.

centre

& reserve

The Hungarian Home Offco is building up a network of, wireless stations over the whole country for the purposes, of criminal in vestigation. The

of the system will be Budapest, where a powerful station with station working on a short-wave length has been constructed. These stations will communicate with 190 receiving stations in Budapest and 3. stations in the Provinces. Budapest will be equipped with an exceptionally powerful receiving station for the purposes of linking

6.30 to 8 p.m.-Programme of up communication from all the in- Victor records supplied by partant foreign police broadcast- Messrs. Taang Fook Plane Co.:ing stations. Zampa Overture" (Herold

Victor Symphony Orchestra, Direction of Nathaniel bi kret.

•

!)

"I'm Falling In Love With Some

one" (Rida Johnson Young. Victor Herbert) and "Moon beams" (Herty Blossom-Victor Herbert). Richard Crooks, Tenor with Orchestra. In A Monastery Garden (Ketel- bey) and "La A Persian Mar- ket" (Ketelbey),

Reginald Foort, Wurlitzer Organ. The Hat My Father Wore Upon St. Patrick's Day" (William Jerome Schwart) and "When

The new system will enable the Hungarian police to ssh over the

hole country all details of crimes committed either at home or abroad a few seconds after receipt of the juformation. Relay stations will" be constructed in the more import and provincial towns as well as the frontier stations, railway junctions,- &e., in order to facilitate inter communication between these thor oughfares.

The central station in, Budapest. will possess a very wide range en- abling Hungary to Broadcast im- over the world. It will be equip- portant police news virtually all' ped for radio telephony and tele- Iriah Eyes Are Smiling photography, the latter for the pur- pose of broadcasting photographs (Olcott Graff, Jr.-Ball), Colin wanted criminals and of clues Olore, Irish Tenor with Orch. of fingerprints. The whole system "Sleepy Valley" (Andrew B. will be in operation by the begin-

Sterling-James F. Hanley) and ning of July. "I'm Just A Vagabond Lover" Zimmer- (Rudy Valles-Leon man), Victor Salon Orchestra. "Beau

"SCREENED GRID." Yout double-gauged condenser should work quite well in the proposed receiver, though you may find it necessary to put a small balancing It naturally follows that a modern

condenser in the second circuit to eceiver of two or three valves.

compensate for any additional caps- gives a far better service than

city in the aerial circuit. For the that obtained from a six or eight For satisfactory volume and receiver suggested you could not de valve set of a few years ago. quality of output or efficient hand-better than follow the diagram of Whereas, in the early days, the line of received energy a correct connections supplied with any good quality of a set was judged by the impedende is the deciding valve make of screened grid valve. number of valves employed, a characteristic. With a knowledge detailed description for construct- three-valve set is now capable of of the ohmic resistance of the coming the complete receiver would, of doing justice to any transmission, ponent the valve is to work with course, involve many explanatory" its quality depending on the circuit an idea of the impedence required diagrams that are beyond the scope

of these columns. and the type of valves used. can be obtained..

NOT A NOTE IS LOST-

So Perfect are the Reproduction Qualities

་་

If a LOEWE FE 63 9 tube set

is used

REQUIRES FRAME AERIAL ONLY WITH NEW BARIUM TUBES, CAN ALSO BE USED WITH LOEWE SHORT WAVE-ATTACHMENT.

Demonstration Hours

11-11,30 a.m. 12.30-1.30 p.m.

During demonstration hours expert Europeau advice is given

on all Wireless matters.

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 signals. Success in picking up these stations also depends very largely upon far- ourable 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.

(Ketzer)

LONG-WAVE STATIONS.

Wave length

Call Kilo Sign cycle KZI.B. 1,153 K.S.M.S. 1,085 C.R.C. 1,070 K.R.C. 967

(Metres) Station

260. Manila 277 Shanghai 280 Tientsin 310 Shanghai 320 Peping C.O.P.K. $45 345 Tokyo JO.A.K. 353 Hiroshima J.O.FK 850 255 Hong Kong Z.B.W. 818 357 Bombay" V.L.B. 840 J.O.I.K 830 J.O.D.K. 820

361 Sapporo 300 Keijo

670

370 Nagoya

370.4 Calcutta

J.O.C.K. 810 V.0.0

800.9

360 Kumamoto 'J.O.G.K.

7001

300 Sendai J.O.E.K. 395 Dairen

770

J.D.A.K.

398 Rangoon

400 Osaka 410 Canton 410 Manila

SHORT-WAVE STATIONS.

STATION

CALL 8151

67.05 Doblutz (Germany)

KILO

760 V.U.R. 754 J.O.B.K. 750 O.M.B, 732 K.Z.R.M. 726

Tr (ons Koxe) OF WORKING

A

A.F.K.434 Mon., Wed. & Fri, 6 p.m. & 2 am,

60.13 Khabarovsk (Euda)EA.97.

A.GJ.

P.E.N

1.M.A.

Q.A.G...

V.S.1.A.B.

4,900 6-10 p..

4,291 Not ingular

4,000 Tacs, Thurs., Sat, 8 pm. 6,806 Sunday midnight

7,142 Daily 6.30 pm, & 11 p.m..

310 Not regular

7,780 Daily 1 p.m.

8,109 Tues. & Fri, 0 pm-1 s..

68.7 Кален

5-5.30 p.m.

50,

Moscow

48.5

Rome

42

Porth

41.8

Singapore

18.8

Kootwijk (Holland)

F.O.L.

37.

Bangkok (Siam)

HS4P.J.

321

Sydney

2.B.L.

9,230 Not regular

| 81.55 | Melbourno

3.1.0...

3:48 Schenectady

W.2.X.A.F.

8,630 Daily Tam.

31.28 Sydney

81.

Nairobi (Kenys)

23.6

Bydney

27,8 Bandoang

Loewe R 533 AC, set with Loud, speaker $130-

gives splendid volume.

"Pertrix" High Tension Dry Batteries

150 volts, 100 volts, 60 volts and 45 volts. Heavy Super Duty, NEW PARTS, RECEIVING SETS and LOUD SPEAKERS

CANTON TRADING

3120 Eindhoven (Holland) | P.C.J.

2.F.C.

7.1.0.

2.M.E.

P.L. Z

25.53 Chelmsford (England)) 5.8.W.-

245 Manila

23.3648chenectady

18.88 Bandoeug

Bandoeng

9.503 Not regular.

9,630 Fri, 8 am, Ust.,3 am, & 10 am,

9,600 Not regular

9877 Midnight daily

10,526 Not regular

11,020 Midnight-3am. daily 11,751 7.30 pm, & &am: dally, except

Saturday and Sunday

K.I.X.B. 12,240 Nightl W.2.1.0. 12,860

Wed 4.m. FH Bat. 18,702 Dally 6.30 pm, to midnight 16.30% Daily 7pm

17282. Delzaam ja midnight. LELP.61 Sundaye 7 pm & midnight

164 Foot (Holland)

PLG

ELF

ASSOCIATION LTD.

18.9 Bangkok

16.88 Haiten (Holland)

P.ELL.

18.3 Kootwijk (Holland)'

16.74-Bandoang

PLE

155

Nancy (France)

18.93 Pittsburg

WS.LK.

31540 Not regular

CARL SCHROTER, Manager-6TH FLOOR; CHINA BLDG. TELEPHONE 24610;

17,700 Daily 10 p.m.

18,404 Each afternoon

19,20 Daily 6.80-7.p.m. `-

19351 Day 8 m.

Soir" (Paul Bourget Claude Debussy) and Clair De Lure" (Paul Verlaine Joseph Szuie, Op. 83, No. 1), Mary Garden, Soprano with Piano,

On the Banks of the Danube " (John Kurucz), John Kurucz, Piano Solo.

WATERFALL BY WIRELESS.

Arrangements are being made ta. broadenst the sound produced by the Falls of Niagara, though it is

not known whether this is to be regarded as an entertainment eager ly awaited by the British public For one of those which Sir John whether they want it or not. In Reith thinks they ought to have

any event, it would probably be "Falstaff-Sul. Fil D'un Soo safer to have some independent Etésio (Verdi) and "La scrutineers present in order that Sonnambula-Ah! Non Credea listeners may have no grounds for Marti" (Bellini), Toti Dal suspecting that they are being fob- Monte, Soprano,

bed off with a waterfall arranged "Gems From The Mikado ""

in the studio by an expert in acous- (Gilbert and Sullivan), Victor tie effects for wireless drama. And Light Opers Company.

when the genuine article has been The Star and Stripes Forever" successfully relayed from North (John Philip Sousa) and "El Amerim perhaps the B.B.C. will Capitan-March" (John Philip give its decision on standard pron- Souea), Leopold Stokowski and unciations for torrents in general, Philadelphia Orchestra.

20 that the waters may come down "It All Depends On You" (Dent. Lodere or on the Zambesi (or Sylva-Brown-Henderson) and even at Irlam or on the Barton "I'm Looking For A Girl Named Mary (Sam H. Stept) Lewis James and Jesse Craw- ford, Tenor with Organ. "Gem from Tales of Hoffman "" (Offenbach) and Gems from *Mignon" (Thomas), Victor Opera Company.

"A Precious Little Thing Called Love" (Lou Davis J. Fred Coots) and Carolina Moon" (Beans Davis-Joe Burke), Jesse Crawford.

aqueduct) with more uniformity of accent and expression. Bloppiness on the part of waterfalls should be tolerated no longer.

TSANG FOOK PIANO COMPANY,

8 to 10.30 p.m.-Chinese programme,

9 p.m.-Weather report. 10.30 p.m.-Close down.

A REAL WORLD-TRANSMETTER,

p.m.

The excellent results achieved by the Telefunken-built short-wave transmitter at Konigswüsterhausen, which broadcasts daily items from the German wireless programme from 2 p.m. to 1.40 a.m. and wire- leas news from 10 to 10.30 (wave-length 31.38 metres), is again" shown by a new series of com- munications which state that the programme has been clearly receiv ed in British East Africa, Brazil, California, Ceylon, India, Java, Manila, and New Zealand. This information has now been supple mented by a further report from Japan. Vice-Admiral Dr M bara, from the Naval Laboratory in Tokyo, states that he can also hear Kocigswusterhausen both clearly and distinctly The world-transmit- ter is thus seen to be fully worthy of the name.

3

HEARING IS BELIEVING.

"Try before you buy" is a good policy to follow if one can find a seller willing to give a trial. Tho Caston Trading Association, Ltd., at their offices in China Building. give demonstrations three times daily of the working of the Lowe FE receiving-sets. From 11 to 11:30 Am 12,30 10 1.30pm and from

5 to 6.30 European demonstrators "VITI 16 ̃plifted to know thotë "In-

terested how the set works and thes results obtained. Advice will be gladly given to those interested in building their own sets, or on any other points connected with wire- less reception.

Des Voeux Road Central

(Entrance Ice House Street) Telephone 24648.

Simplicity itself

One-motion tuning. Simplified circuit. Units all interchanges. able.

There's nothing like

Victor

Radio