1931-01-22 — Page 2

HONG KONG DAILY PRESS, THURSDAY, JANUARY 22, 1931.

TADIO

FEATURES

HOW TO MAKE MAINS WORKING

SAFE.

POSSIBILITY OF SHOCKS CAN BE AVOIDED

BEWARE OF FAULTY TWISTED FLEX LEADS,

certain eliminators employing an electrolytic action, and when top. sum you can buy insulated switches ping up the rectifier cells the which are connected in the flex line | makere' instructions should be care. itself, and those completely insulatefully followed. A certain amount of the eliminator.

would secur that many people shock, if only a small one,, by touch are still of the opinion that thereing the other wire. For a small is a constant danger of shooks, and perhaps even greater harm, with' high or low-tension eliminators, and although much of this prejudice exists from the early days of eliminators when manufacturers did not turn out apparatus complying with the LEE. regulations, there is no doubt that many good units to-day give trouble and subsequent ly blow up" or fuso because they are poorly fitted,

Mains eliminators are generally supplied complete with a length of flex for the maina input, but it must not be overlooked that in the cheaper eliminators, 'some of the flex is really dangerous after about twelve month's usu, for the rubber porishes and short circuits are Ekely to happen, and if they do happen the house fuse blows-not in itself a serious thing but sufficient to

average non-technical".

make the rudio inan believe that the mains unit is dangerous.

This one he cared at its source

here.

Bafety With Pluge.

trouble arises in some eliminators because their users forget that the voltage given is greater than that of the dry batteries generally used. Even an extra 50 volts high tension in a set may cause trouble unless provision is made for this greater voltage.

Many mains-set users have wrong ides about fuse-blowing. If a las blows through a fault in an eliminator or in its connections, do not blame the fuse! A fuse is the safety valve of an electrical circuit. For safety's sake you should have a fuse in each mains lead, in the.

Cheap paper-dielectric condensers eliminator; itself, at the input terminals to it, or down by the of doubtful manufacture may stand mains ping. Small insulated frees up to a steady BD to 100 volts from u dry battery, but the insulation can be purchased for this purpose.

It is no use fitting a fuse unless a break down under the strain of the 120 or 160 volts given by a a rendy supply of fuss wire is al

mains climinator. It should be re- hand in case of a blowout.. A small spool of dampre fuse wire

membered, too, that if an eliminator should be hung near the mains fuso box of the house, while thinner wire should be at hand near the mains eliminator.

is not switched on properly, a surge voltage is produced, which may mount to 500 volts or more, and good condensers are needed to stand up to this.

See Parts are Firmly Fixed.

The proper way to control a set If you buy an eliminator of taking high-tension from the mains good make you need have no fear is to switch on the valves before by fitting stouter flex if it appears that it will give trouble through turning on the mains, and, similar. necessary. Ordinary twisted light internal short circuits. The generally, to disconnect the mains before ing flex is obtainable in several practice now-a-days is to paint over the low-tension switch is turned off. thicknesses, and as only a couple the components with a heavy in- Another safety point, so far as the of yards or ao will be needed, there'sulating compound when all wiring set is concerned, is to make sure is no point in saving a few cents is done, and this, obviates the posthat when a trickle-charger is fitted, sibility of short-circuits. If you the valves are not harmed by the make up your own eliminator you increased should take equal care to see that all the parts are firmly screwed to the base-board so that they cannot rattle loose and touch one another In most alternating current elimina tors there is a certain amount of ly insulates the eliminator when it vibration of the power transformer is awitched off. Generally it and choke, and this must be watch- "breaks" only one of the wires, and with most mains circuits this means that you can still get

On no account make twisted con- nections to the mains point, but employ a proper recessed-contact plug and socket. It is not sate to assume that the switch, naually 6tted to domestic wall-plugs cutire

ed.

Some eliminators are provided with metal rectifiers, but there are

accumulator voltage. With most eliminators the high- tension side is switched off when the trickle charger is brought into circuit, but even so, as the charger.

'comes into action, the accumulator

voltage may rise from its normat 1.9 or 2 volts up to as much as 2.5 volte, and the continued effect of this is bound to harm the, valves. It is a bad plau to keep the set in operation while the trickle-charger is switched on.

HAVE YOU HEARD THESE?

Here are lists of long-wave- and short-wave stations which should be picked up by anyone in Hong Kong pho bis a mode. rately good of suitable for re- calving such signals. Success in picking up these stations also dependa very largely upon fav. ourable atmospheric conditions. Readers ara invited to add to this list should they sucosed in picking up ang station not in. cluded in either of those lists.

LONG-WAVE STATIONS.

Call · Kilo-

Wave. length (Metres) Station Sign cycle 260 Manila K.Z.I.B. 1,153 277 Shanghai K.S.M.S. 1,085 280 Tientsin C.R.O.1,070 310 Shanghai K.R.C. DOT 320 Peping C.O.P.E. 945

J.O.A.K. 345 Tokyo

870 353 Hiroshima J.O.F.K

650 385 Hong Kong Z.B.W. 840 337 Bombay V.U.B. 840

J.O.I.K. 381 Sapporo 360 Heijo

J.O.D.K 820 370 Nagoya J.0.0.K. 810 370.4 Calcutta V.0.0 BOR,9

700 J.O.H.K. 7:0 J.D.A.K. 760 V.U.B. 754 J.O.B.K. 750 C.M.D, 73% K Z.B.M. 790-

380 Kumamoto J.O.G.K.. 300 Sendai 305 Dairen 398. Rangoon

400 Osaka 410 Canton 413 Manila

SHORT-WAVE STATIONS.

STATION

CALL 810K

07.05

Dobints (Germany)"

A.F.E.

c0.13

Khabarovsk (Russia)RA07.

58.7 60,

Naug

A.G.J.

Moscow

REN.

49.8. 12,

Home

P.M.A

Perth

GA.G.

41.9 38.8 87. 32.6

Singapore

V.9.1.A.D.

Bangkok (Siam)

Kootwijk (Holland)

P.CL

11.55

Bbourne

81,48 Sebenectady 21.20 Eindhoven (Holland) 81.28 6ydaoy 81. Nairoul $8.5 Sydney

HSLPJ.

orry

STALO

TIME (HORG Kore).

or WoчKING

600

4,434 Mon, Wed, ♣ Fri., 0 p.m, & 2 ọ.m. 4,090 8-10 p.m.

6,291 Not regular

6,000 This, Thura, Sat, 8 pm.

9,800

Sunday midnight

7,142 Dally 8.30 p.m. & 11 p.m.

7,910 Not regular

7,780 Dally

8,108 Tuos, & Fr., 9p.m.-1 a.m

9,503 Not regular

9,630 Daily 1 a.m.

الرسمي

3,020 FY, & Sat, 3 am. & 10 nm,

&...

9,560. Not regular-

9,077 Midnight daily

10,628 Not regular 11,020

11,702 120 am, daily.

&sam, daily, except

Saturday and Sunday

11 p.

2.B,L,

9,280 Not regular

3.L.0.

W.3X.AF

.P.C.J. ·

2.5.0.

(Kopya)

9.M..

27.8 Bandang

P.LE.

20.00

Chelmsford (England) 6.8.W.

18.88 18.4

24.5 Manila 28.86 Bobanectady

Boadoang

W.L.X.O. P.LG,

Kootwijk (Bolland)

P.C.L

37,4 16.0 16.8

Bandoong

Bangkok

Kootwijk (Holland)

PC.K.

16.74 Bandoung

PIE

18,6 18.98

Nancy (France) Pittsburg

W.8.X.K.

K.1X.R

P.L.F.

H.S.1.P.J.

12,240 Nightly

12,850 am. Wed., Fri., Sat.

16,102 Daily 080 p.m. to midnight

10,304 Daily 7 p.m.

17.280 Daily 8 p.m. to midnight

17,751 Sundagi 7 pm, & midnight.

18,404 Each afternoon

10,220 Daily 5.80-7 p.m.

19,351 Daily's 1.

21,540 Not regular

[Allowance must be made for "summer-time" in most Euro- pean countries, which is one hour ahead of true time]

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PROGRAMME.

BROADCAST BY ZB,W, ON 333 METRES.

11 to 11,30 a.m.--Stock quotations. 11.30 am-Chinche programme. 19.30 p.m.-European programme. 1.30 p.m.-Weather report, local time and commercial Press

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2 p.m.-Close down..

4 to 8 p.m.-European programme

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7 p.m.-Stock quotations.

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