1933-01-12 — Page 2

Page

MARCONI DOES THE IMPOSSIBLE

27

RADIO TESTS BEAT THEORY

NEW ERA FROM SHORT WAVES

results, however, which he obtained during the period, 1919-24 with the use of waves from 10 to 8 metres-- which led to the collapse of the long wave Imperial scheme--bad aquin districtod his attention from the study of very short waves,

HONG KONG DAILY PRESS, THURSDAY, JANUARY 12, 1933.

HEART OF THE TELEPHONE

LONDON ROOM THAT SERVES THE WORLD-

"The rhw system," he said, ja. now available for advantageously replacing-optical or light signalling in all its long distance applications,

London's unchallenged position much as between signalling stations as the heart of the world's telephone along coasts, or between forts along system has been consolidated by the a frontier. In general, it will be bringing into use in Carter-lane of found advantageous where the erec. the latest and most efficient inter- Marchese Marconi threw downtion" and maintenance of an ornational exchange in existence. the gauntlet to orthodox science dinary short distance telephone or

last night when ha. discussed the cable aireuit is difficult or too ex. i time, talking in English, French,

WANE

possibilities of ultrashort wireless communication in a dis- course delivered before the most crowded audience the Royal Insti- tution has ever known

pensive."

Though the present experiments were begun only 18 months ago, he had been considering the problem of using these very short waves ever since his first wireless experi inments.

on

Ninety girls work in it at one

and German do all parts of the Con, tinent, and there is an elaborate system af hidden tubes and chuter for carrying tickets and records of culla

He has recently succeeded

Noise-proof asbestos ceiling and transmitting ultra-short waves over

cork floor dull the sound of n distance of 188 statuto miles-- Short Wave Advantages.

mechanism and voices, and the chief about a hundred miles further than

characteristic of the long “L”. present "theory will allow-and

of "Long experience taught me," shaped room-with its rows he now hints that he hopes still he added. not always to believe Town, and dull silver switchboards further to upset accepted ideas. in the limitations indicated by twinkling with tiny yellow, red, theoretical considerations and green lights-is its quiet. The In these words Marcheses Marconi | purely

or even by calculations, for these place has an almost awe-inspiring kumanrized to a representative of

insufficient quality of quiet. Even the seven- the Morning Post" after the are often based

osture his conception of the future knowledge of all the relevant Ine teen 24-hours clocks are silent. of these very short waves, in the tors, but, in spite of adverse fore-

Among the fascinating devices case of his record-breaking experies, to try out new line of shown me recently by the Con-

research, however moet of a wave length of about 29

unpromising timental supervisor were the stops aches:

they may seem at first sight.

of coloured glass at each switch "There is a certainty of improve.

About 18 months ago I decidboard behind which numerals from spent of a wave length of about 22rd again to take up the systematic one to eighteen become illuminated communication; and a possibility

investigation of the properties and in turn, inexorable records of the of still further benting theory by characteristics of these very short number of minutes of any call. It extending transmissions to distan waves in view of the advantages is consoling to know that directly ces even further beyond the condi. which they seemed to offer.".

a caller replaces his receiver he tion of straight-line communication

stope the expensive march, of this

time record. which until this thought aecessary,

nummer

was

|

"As regards broadenst possibili- ties I cas say definitely that these waves will go through a wall. What the limitations would be in a city remains to be seen. Prob. ably rather longer waves would be necessary for this purpose.

"I have also in mind the pas sibilities of applying them to teleti. sion, Between a wave of four in ches and one of eight inahes they would be as many channels of com- munication available ne between

the whole range from 200 to 400

metres.

1901 Tests Recalled,

of these waves is concerned I can-

and

arm

Marchese Marconi described the tests, made with these waves and made public for the first time de tails at the apparatus used.

reflected by small metal rixis, He showed how these waves could

how even a movement of his was sufficient to affect the a strength in the neighbour. hood of the recording instrument, Marchese Marconi then told the dramatic story of how the range of these waves had been extended The first really striking result, he explained, was obtained early in August, when signals were received by his yacht Elettra at a distance up to 125 miles from the Rocca di Papa, near Rome. The theoretical limit in that case was 32 miles.

Passing to regular development's he stated that the first permanent So far as extending the range link between the Vatican City and mt forget that at the very time the Pope's palace at Castel Gan when I was rending and receiving dolfo over a land distance of about waves 3,000 miles across the Atlan 12 miles had been working satis tia Oceania 1001, distinguished factorily for a month although it mathematiciaris were writing equa- would be another month before it tion which proved that such com. munications would be limited to a distance of about 100 miles. We must try everything whether it ecems possible or impossible."

The principal advantages claimed by the new system by Marchese Marconi during his discourse were that it was unaffected by fox and atmospheric, offered a high degree of ecmey by virtue, principally, of its sharp directive qualities, and that the transmitting and weeiving apparatus were very much more compact.

In this connection he recalled that it was the exigenoies of war which first directed renewed atten- tion to the directive properties which were practically inherent in very short waves. The remarkable

BRUNSWICK

AND

MELOTONE RECORDS

FOR

JANUARY

was formally inaugurated.

ሰ Very

Fluent Linguists.

in French and German himself.

The supervisor examines the girls. and he requires a high standard of oral fluency. The tolephonic busi ness of all Europe, he told me, is conducted exclusively in English, French, or German. Afore than thirty of the girls speak good Ger- man, and double that number know French.

The exchange has, among many

circuite qiher, thirty-three

(or

Enes) to Paris, nine to Berlin, six to Hamburg. ten to Amsterdam,

..

INVESTIGATING THE ETHER

PROGRESS OF RADIO RESEARCH

EXPERIMENTS ON SHORT WAVELENGTHS

The report for 1031 of the Radio Research Board of the Depart ment of Scientific and Industrial Research contains a record of experiments to supply formules such as can he used by the practical radio engineer.

A number of experiments in communication on wavelengths ander 10 metres have also produced valuable results.

THE CAUSE OF FADING-

The Department of Scientific and approximately between Bodmin and Industral Research issues to-day Launceston. the report of their Radio Research Board for the year 1931, summaris-1

presence of down-coming radiation

on 5.5 metres. Signals were receiv ed from Rugby at a distance of 41 miles, two different transmitters, being used. One fed 150 watts into the beginning of a transmission lihe leading to a half-wave antenna at the top of a mast 890 feet high; the other put. a power of about 2 kilowatts into an antenna at the top of a mast 40 feet high. The receiver was in the optical path of the low- power elevated transmitter, but not in that of the more highly powered

set.

ི ༄

"As it was found that signala were very weak with an aerial close

the ground, the receiving aerial' was arranged as a half-wave rod. capable of rotation about a horizont- nl axis, fixed on a mast 20 feet high.

די

TO-DAY'S WIRELESS

PROGRAMME.

BROADCAST BY Z.B.W ON 355 METRES

to 11.30a.m.-Stock and ex change quotations, weather re port, etc.

11.30 am-Chinese recorded", pro-i

gramme.

1830 p.m.-European programme of

Victor and Brunswick records..

1 pim-Local time and weather

report.

1,30 p.m.-Rugby Press news, select- ed London and New York stock. quotations, etc...

12 p.m.-Close down,

5 to 8 p.m.-European programme.

3 to 6 p.m. A relay of the Re- vellers' Dance Orchestra from the Hong Kong Hotel Roof Garden by courtesy of the Man- agement. (During the intervals recorded music will be broad- cast from the Studio.)

EFFECT OF HEAT. "While receiving the Rugby transmissions on Bredon Hill it was observed that there was a distino. diurnal variation of signal strength, On a hot day it was found that the strength gradually diminished towards noon and at- tained a minimum at about 1,400 G.M.T. thereafter gradually im proving till early morning strength 6. was regained towards 1800 G.M.T." Further testa made by the Board 6 on "dull autumn days support this theory..

The effect of a hill in causing ing work carried out during the such a drop of signal strength was year dealing mainly with the funda- further investigated under better mental study of the electrical state conditions by measurements near of the upper atmosphere and its Tavistock, in Devonshire. On the induence on the propagation of side of a hill whose crest interven

A number of experiments are also wireless waves of all frequencies the ed between transmitter and receiver principles and improvements of a signal of 24-millionths of a volt recorded on wave-lengths of 1.6 method of rady direction-finding, per met was measured. Ono mile, metres.

The report indicates that con the study of atmospherics from the farther up the hill, travelling to- standpoint of radia communications wards the transmitter, this dropped and meteorology, the development to 1.5m/m, but rose, to imv/m.siderable progress has been made perfect direction-finder for medium of radio frequency standards, and immediately over the crest of the towards the development of the

hill." the improvement of electrical grea-

waves, free from errors caused by surements, nt high frequencies,

down-coming waves occurring most- ly at night. The report also 'show's that accurate direction finding should soon be possible on short waves. Hitherto this has been deem- ed impracticable, but the difficul- ties are now evidently being rapid. ly overcome.

THE FUNDAMENTAL QUESTION

SHORT-WAVE COM- MUNICATIONS

The results of a number of experi- ments are summarised in the report for communication carried out to test the possibility

purposes ofi waves below 10 metres.

point out, may at first glance ap The work outlined, the Board pear to be a group of independent experiments, each set in motion to solve a separate engineering prob Tests were carried out at tlu lem The Board show, however, Radio, Research Station, Slough, that the separate threads of the with various types of receivers, to programme, especially on the pro-i endeavour to receive signals from interweave Rugby on wavelengths of, 3.5, and pagation of waves, into a single fabric. The whole 5.5 metres and also from s.5. Belgen- aim of this work," the report land, when on a world cruise, mak states, is to answer in figures the ing periodical transmission on 4.5 question, What signal will be re- and 7 metres.

"On no occasion,” ceived at any point on the earth

was it possibla from a fully specified transmitter the raport states,

All the ex: to receive signals from either trans- Just after the war England had perimental and theoretical work immitter." By means of portable re

at any other point telephone commanications with only progress in our own and in all the two countries, France and Belgium. other radio research establishments ceiving apparatustests were made Now practically every country if the world is necessary, but not on Bredon Hill, near Evesham, to Bufficient, for a full answer to this investigate the possibility of the question. The propagation of radio waves is certainly no exception to the general experience that oven the simplest train of operation in real life is so complex that, the full de-

and two to Madrid.

the world is, connected directly or with only one joint to London, which is the central junction for carly al! inter-Contiriental calls.

It was of particular interest, he said, that this was cot only a case of land communication short waves, but that the two sta- trees both in the Vatican Garden tions were screened by intervening land can now speak through his and the avenue on the Janiculum on instrument to 85 per cent, of

the telephone users in the world.

Hill.

A subscriber anywhere in Eng.scription of the physion! processes brought into play is impossibly

HAVE YOU HEARD THESE?

Eere are lists of long-ways and short-wave stations which 'should be pläked up by anyone in Hong Kong who has a mode- rately good net suitable for ze- colving such signals. Success in picking up these stations also depends very largely upon fav. 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.

LONG-WAVE STATIONS.

Wave length (Metres) Station 200 Manila 277 3banghai *346 Tokyo

Call Kilo- Sign cycle K.Z.I.B. 1,183 K.S.M.S. 1,093 J.O.A.K. 370

353 Hiroshima J.O.F.K 850 355 Hong Kong Z.B.W. 846 357,1 Bombay 361 Sapporo

306 Keijo

370 Nagoya

370.4.Calcutta

V.U.B. 840

J.O.I.K. 680

J.O.D.K. ao

Inbourious."

An attempt is now being made, according to the report, to express the effect of the upper atmosphere on radio waves by a mathemation?! formula and to evalunta this for mula numerically for typical cases, so that the resulta can be used by the practical radio engineer.

To do this, experimental data regarding the number of electrified particles in each cubic inch of the various layers of the upper atmos- phere is being found by shooting from a wireless transmitter jabs of

energy, each lasting about 10000th WITH EVERY $5,00 of a second, vertically upwards, and measuring the time interval which alapses before the energy returns to a point near the transmitting station.

REASON FOR FADING

The effect of the earth's magnetic J.0.0.K. BIO field on each jab of current is also V.U.C.800.9 being studied. It has been, found

380 Kumamoto J.O.G.K. 790 that the energy in the jabs is split 390 Bends 1.0.H.K. 770. by the joint effect of the electrical 305 Dairene J.Q.A.K.

400 Osaka

410 Canton

480 Manila

SHORT-WAVE STATIONS.

KILO

CTCLMA

760.

J.O.B.K 750 C.M.B. 739 K.Z.R.M. 825

(Hora Kono) OF WORKING

particles in the atmosphere and the magnetic field of the earth into two portions which, return to the earth at slightly different times, while the forces composing them are differ ently orientated. It has been shown. that these two parcels of energy which make up the received signal are differently absorbed in the atmosphere. The interaction of these two and the portion of the energy travelling by different air routes or along the ground cause

4,484 Mon., Wed. & Fri, 0 p.m. & 3 x.m. the fading of signale

STATION

CALL SION

67.65 60.12 £8.7

Dobintz (Germany) A.F.K Khabarovsk (Buska) B.A.97. Nauenw

4,990 6-10 p.m..

A.G.J.

6,291 Not regular

B.E.N.

6,000 Tue, Thurs., Sat, 8 p.m.

6,996 Bunday midnight

150. Mosco

48. Bome

42,6 Perth

|413

88.8

35.2

81.56

81.48

31.30

BL88

(Holland)

Bangkok (Slam)

Gydaey

Melbourne

Behenectady Eindhoven (Holland)

Sydney

(Kenya) *

1.MA

(BA.G.

V.S.L.A.B.

{P.C.L.

HSAFJ.

2.B.E;

7342 | Daily 5.80 p.m; & 11 p.m. 7,310 Not regular

7,780

8108 11

8,108 Tues, deal-Im

9,280 Not regular 9,508 regular W.3.K.A.F. 9,600 Dally am

B.L.O.

Sydney Handoong

PLE Chelmsford (England) | 6.8,W/)

TSANG FOOK PIANO Bohenectady

COMPANY,

28.85

36,5 -17.8- 25.53

25.66

18,4 17.4

-16.0

10,8

15.74 Bandoing.

Hanila

Bandoang Kootwijk (Holland) POL P.L.F. Handosag

H.8.1.P.J Bangkok

(Holland) POL

P.LEA..

W.LXO. P.LG

[W.8.X.X.

Trl, 8 am, Sat. 8 am, & 10a.m. 9,620 8,690 Not regular

6,677 Midnight daily 10,328 Not regnies, 811,020

110 Minbatmā Km. daily.

11,751790 Saturday and Sunday

&a.m. daily, except 1:13:200 12,880

FL., Bal 16,102 Daily 6.80p, to midnight 18,304 Daily Y

7pm 17280 Daily 8 pm to midnight 17,751 Bundays 7 pm & mlinight

| 18,404|| Each afternoon.

19,220 Daily 5:30-7 pa

15,361 Daily AAM.

21,540 Wot regular

· A RADIO SHADOW Broadcast listeners in the West of England will be interested in the observations recorded on the field trength of Daventry (5XX), in Cornwall.

"Reception in Cornwall has for some time been know to be excep tionally poor, and has engaged the attention of several workers. In particular, one published group of, measurements suggested that the beam transmitting stations at Bod-

remainder of the Duchy A series of measurements were therefore undert by the Board, from which it appears that the cause of the rapid attentiation-which-cOCULTE west of Launceston, also the pecu- liarly shaped contours

strength plotted in Comiwall, is the large

arly" maped" moor

the Bill, Bro tibi..

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(Continued on: Page 1)

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